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Introduction
Aaron Louis Treadwell was a prolific polychaetologists with a long series of publications describing polychaetes with the proposal of many new species, of which 36 were nereidids proposed from 1901 to 1943 (Hartman, 1956). Hartman (1956) highlighted that Treadwell had scarce laboratory equipment and limited access to bibliography, and along with his schematic freehand drawings from memory, explained his purported problems when describing species and why most of his species were regarded as junior synonyms by herself and other. It is comprehensible that a large number of names were synonymized due to the prevalence at that time of preserving the oldest name (mainly European) and the idea of the existence of few cosmopolitan species with large ranges of morphological variation promoted by prominent colleagues (Hutchings & Kupriyanova, 2018), coinciding with a period (1930-1960) with few proposals for new names (Pamungkas et al., 2019).
Although Treadwell’s species descriptions are sometimes succinct and the figures schematic, at least in nereidids they are accurate in most cases when compared to the original material. Some problems found in the works describing nereidids are the proposal of replacement for preoccupied names, and the lack of comparison of his new species with pre-existent ones in several cases, even with their own. Some nereidids described by Treadwell have already been redescribed and accepted as valid; however, the validity of most of them is pending to be re-assessed. Some examples are the species Nereis arroyensisTreadwell, 1901, Nereis disparsetosaTreadwell, 1932, Nereis largoensisTreadwell, 1931, and Perinereis diversidentataTreadwell, 1943.
In one of his early works, Treadwell (1901) proposed Nereis arroyensis based on specimens from Arroyo, Puerto Rico. The description is succinct and included 2 drawings of the head and a parapodium, presumably an anterior one but not clearly stated (Treadwell, 1901), avoiding giving more details in a later work (Treadwell, 1939). Hoagland (1919) recorded the species from Cayo María Langa, Puerto Rico. Hartman (1956) examined the holotype and described the pharyngeal features for the first time but no additional features or figures were included, and Rullier (1974) recorded Nereis arroyensis from La Habana Bay based on the original description. Although its validity is not in doubt, some key features used in current descriptions are missing from these descriptions, requiring further evaluation of their morphology.
Nereis brevicirrataTreadwell, 1929 was described based on a single specimen from Key Largo, Florida, but later Treadwell (1931) proposed Nereis largoensis as a replacement name because the homonymy with N. brevicirrata Treadwell, 1920. Hartman (1956) regarded it as a subspecies of the stem species Nereis pelagica Linnaeus, 1758, but recognizing some differences such as the presence of paragnaths in area V and larger notopodial lobes in posterior chaetigers in N. pelagica largoensis, and by having a different shape of blades of notopodial homogomph falcigers than another regional subspecies Nereis pelagica occidentalis Hartman, 1945. In the same year, Pettibone (1956) examined the type material of N. largoensis, synonymized the subspecies Nereis pelagica largoensis with N. pelagica, but regarded Nereis pelagica occidentalis as distinct from N. pelagica and gave it the status of species; N. occidentalis has been recently redescribed based on type material (Salazar-Vallejo et al., in press) to distinguish it from the Nereis falsa species complex, while N. largoensis remained as a junior synonym of N. pelagica. Nereis largoensis has been recorded from Isla de Providencia in the Colombian Caribbean (Báez & Ardila, 2003; Dueñas, 1999).
Treadwell (1932) described Nereis disparsetosa from São Paulo, Brazil based on 2 complete specimens, and included a comprehensive description and 5 line drawings of the head, parapodia, and chaetae. As in other several cases, Treadwell did not contrast this new species with another one described by himself, Nereis (Neanthes) palpataTreadwell, 1923, or Nereis coerulea, N. microphthalma, and N. obscura, proposed by Hansen (1882). Hartman (1938) examined the type material of both Treadwell’s species, transferred Nereis (Neanthes) palpata to Pseudonereis, and regarded N. disparsetosa and Pseudonereis atopodon Chamberlin, 1919 as junior synonyms of P. palpata, but the additional features included and explanations of the synonymies are somewhat scarce. Bakken (2007) redescribed P. palpata and P. atopodon in detail, but overlooked the synonymy with N. disparsetosa.
Treadwell (1943) proposed Perinereis diversidentata from Cape Cross, Namibia, and included a comprehensive description and 7 figures describing the head, shape, and arrangement of the paragnaths of some areas, parapodia, and chaetae. Day (1953) regarded P. diversidentata as a junior synonym of Pseudonereis variegata (Grube & Kröyer, in Grube, 1857) from Chile, and Hartman (1956) agreed with Day’s decision. Later, Bakken (2007) and Conde-Vela (2018) overlooked this synonymy in their respective works when redescribing P. variegata, as for Kara et al. (2018) that reinstated a similar species from southern Africa, P. podocirra (Schmarda, 1861), without mentioning Treadwell’s species. Therefore, a re-assessment of the validity and a redescription of Perinereis diversidentata is needed.
The aim of this work is to redescribe Nereis arroyensisTreadwell, 1901, Nereis disparsetosaTreadwell, 1932, Nereis largoensisTreadwell, 1931, and Perinereis diversidentataTreadwell, 1943, based on the examination of type material, to present more details on their morphology. Moreover, a commented table including all nereidids described by Treadwell is also provided.
Material and methods
Type specimens examined are deposited in the American Museum of Natural History, New York, USA (AMNH), and the National Museum of Natural History, Smithsonian Institution, Washington, D.C., USA (USNM).
Specimens were examined under stereomicroscope and compound microscopes for observing parapodial and chaetal features. Some parapodia along the body were removed and mounted in semi-permanent slides with ethanol-glycerol and examined under the compound microscope. Photographs were made using a Sony Alpha-6000 provided with an adapter for both microscopes. A set of photographs were digitally stacked to improve the depth of visual field with Zerene Stacker and post-processed with Adobe Photoshop.
The terminology proposed by Villalobos-Guerrero and Bakken (2018), Villalobos-Guerrero (2019), and Conde-Vela (2018), for parapodial and pharyngeal features was followed; whereas the description of chaetal shafts and the measuring of parapodial structures followed Conde-Vela (2021a).
Descriptions
Order Phyllodocida Dales, 1962
Family Nereididae de Blainville, 1818
Genus Nereis Linnaeus, 1758
Type species. Nereis pelagica Linnaeus, 1758, by subsequent designation (Hartman, 1948).
Diagnosis followed: Bakken and Wilson, 2005.
Nereis arroyensisTreadwell, 1901
Figure 1 Nereis arroyensisTreadwell, 1901. Syntypes USNM 16005. A, Anterior end, dorsal view; B, posterior end, dorsal view; C, pharynx, dorsal view; D, same, ventral view; E, close-up of midventral region of oral ring (labels point ridge (uppercase) and furrow (lowercase) regions of the midventral region). Scale bars: A, B, 1 mm; C-E, 0.5 mm.
Figure 2 Nereis arroyensisTreadwell, 1901. Syntypes USNM 16005. A, Chaetiger 2, right parapodium; B, chaetiger 12, right parapodium; C, chaetiger 32, right parapodium; D, chaetiger 63, right parapodium; E, notopodial homogomph falciger, chaetiger 63; F, sub-acicular heterogomph falciger, chaetiger 12. A-D, 0.2 mm; E, F, 10 µm.
Pygidium swollen, as long as wide (Fig. 1B); anal cirri cirriform, long, as long as last 7 chaetigers (Fig. 1B).
Nereis arroyensisTreadwell, 1901: 193-194, Figs. 30-31.
Hoagland, 1919: 574 (list only). Treadwell, 1939: 223, Fig. 48. Hartman, 1956: 280. Rullier, 1974: 37.
Description. Syntypes (USNM 16005) in good condition, one small, incomplete. Largest complete, 43 mm long, 2 mm wide at chaetiger 10 excluding parapodia, 70 chaetigers. Body pale, pigmentation absent, body tissue translucent toward posterior end (Fig. 1 A, B).
Prostomium subpentagonal, as long as wide; anterior region distally entire, subtriangular, slightly longer than posterior region (Fig. 1A); anterolateral gap between antenna and palpophore as long as diameter of antennae (Fig. 1A). Antenna of left side distally incomplete, right one digitiform; antennae not passing the palps, gap between antennae very small (Fig. 1A). Palpophores ovoid, swollen, 1.5 longer than wide, shorter than prostomium, subdistal transverse groove present (Fig. 1A). Palpostyles subconical (Fig. 1A). Eyes almost entirely faded, reddish, anterior and posterior pairs rounded, subequal, in trapezoidal arrangement, eyes diameter slightly shorter than basal width of antennae, lenses visible, anterior big, covering almost all eye (Fig. 1A). Tentacular belt 1.5 times longer than chaetiger 1, partially covering posterior pair of eyes (Fig. 1A), with a small ventral flap (Fig. 1D). Tentacular cirri smooth, cirrophores ring-shaped, cirrostyles cirriform; posterodorsal tentacular cirri missing in larger specimen (Fig. 1A), in smaller syntype reaching chaetiger 4. Pharynx everted corrugated, partially dehydrated, oral ring 1.5x wider than maxillary ring (Fig. 1C, D). Jaws with inner margin dentate, more than 8 teeth (not extracted) (Fig. 1C, D). Maxillary ring: I = 3 cones in a vertical row; II = 17-18 cones in arc; III = 42 in a large rectangle; IV = 32-38 cones in round (Fig. 1C-D), merged paragnaths absent. Oral ring: V = 0; VI = 6-7 in a rectangle; VII-VIII = 98 small cones in 2 bands, anterior band with 32 paragnaths placed in ridge regions A-C and furrow regions a-c; posterior band with 66 paragnaths placed in ridge regions A-E and furrow regions a-e (Fig. 1C-E). Furrow pattern of areas VI-V-VI, λ-shaped (Fig. 1C). Dorsal cirrus digitiform in first 2 chaetigers, filiform thereafter, attached basally to dorsal ligule in anterior chaetigers, medially thereafter (Fig. 2A-D); 0.8x length of distal region of dorsal ligules in anteriormost chaetigers (Fig. 2A), 1.3-1.4x longer in anterior and middle chaetigers (Fig. 2B, C), 2.5x in posterior chaetigers (Fig. 2D). Dorsal ligule with distal region longer than proximal ones in anterior chaetigers, becoming shorter toward middle and posterior chaetigers (Fig. 2A-D). Distal region of dorsal ligule subconical throughout; 1.8x longer than median ligule in anterior chaetigers (Fig. 2B), 1.2x in middle chaetigers (Fig. 2C), 0.8x length in posterior chaetigers (Fig. 2D). Median ligule subconical with blunt tip in anteriormost chaetigers, slightly lanceolate in anterior and middle chaetigers, subconical with pointed tip in posterior ones (Fig. 2A-D); 1.8x longer than neuroacicular ligule in anterior chaetigers (Fig. 2B), 1.5x in middle chaetigers (Fig. 2C), 2.5x in posterior chaetigers (Fig. 2D). Neuroacicular ligule subconical throughout, superior and inferior lobes absent (Fig. 2A-D). Neuropodial postchaetal lobe rounded, shorter than neuroacicular ligule throughout (Fig. 2A-D). Ventral ligule subconical with blunt tip throughout; 3.4x longer than neuroacicular ligule in anteriormost chaetigers (Fig. 2A), as long as in anterior chaetigers (collapsed in Fig. 2B), 1.4x in middle chaetigers (Fig. 2C), 2x in posterior chaetigers (collapsed in Fig. 2D). Ventral cirrus digitiform in first chaetigers, filiform thereafter (Fig. 2A-D); 0.5x length of ventral ligule in anteriormost chaetigers (Fig. 2A), 0.8x in anterior chaetigers (Fig. 2B), 0.5x in middle chaetigers (Fig. 2C), 0.7x in posterior chaetigers (incomplete in Fig. 2D). Aciculae amber throughout, becoming lighter toward posterior chaetigers (Fig. 2A-D); notoaciculae absent in first 2 chaetigers (Fig. 2A); both noto- and neuroaciculae of similar thickness throughout. Most chaetae broken or blades missing. Notochaetae consisting of homogomph symmetrical spinigers and falcigers. Spinigers with blades pectinate, teeth minute, decreasing in size toward blade tip, replaced by homogomph falcigers in posterior chaetigers. Falcigers with symmetrical rim of shaft; blades slightly falcate, 6 coarse teeth, one third of inner margin edentulate, blade tip stout, tendon not observed (Fig. 2E). Neurochaetae consisting of homogomph spinigers and heterogomph falcigers in supra-acicular fascicles, heterogomph spinigers and falcigers in infra-acicular ones, most blades detached or broken. Spinigers with blades as in notopodial ones. Infra-acicular falcigers with blades pectinate, teeth increasing in size toward distal end, blade tip stout, tendon not observed (Fig. 2F).
Taxonomic summary
Material examined. Syntypes USNM 16005 (2), San Juan, Puerto Rico, 567 m depth, 13 January 1899, Coll. R/V Fish Hawk.
Remarks
The original description is very brief and general and later Hartman (1956) detailed the paragnaths arrangement and jaw morphology and agreed with the current description. Some key features added are the arrangement of paragnaths in the furrow and ridge regions in pharyngeal areas VII-VII and the VI-V-VI furrow pattern, unambiguous descriptions of changes in the parapodia along the body, the presence of notopodial homogomph falcigers, and the description of the posterior end.
In their key to species of Nereis from the Grand Caribbean, Ramírez-Hernández et al. (2015) grouped N. arroyensis with species having longest tentacular cirri reaching chaetiger 6, but this feature was not provided in the original description. Moreover, Ramírez-Hernández et al. (2015) used the feature ‘anterior pair of eyes crescent-shaped’ based on the original description, but in the holotype they are rounded with big lenses, and the remaining reddish tissue is crescent-shaped. This feature separated N. arroyensis from N. riisei Grube & Ørsted in Grube, 1857, N. lamellosa Ehlers, 1868, and N. rigida Grube & Ørsted in Grube, 1857. However, N. arroyensis differs from N. riisei by having several paragnaths in areas VII-VIII arranged in 2 bands, whereas N. riisei has 5-6 paragnaths in a single band; and N. arroyensis differs from N. arroyensis differs from N. lamellosa and N. rigida by lacking paragnaths in area V. Nereis arroyensis has a very distinctive arrangement of paragnaths compared to the Nereis species recorded from the Caribbean Sea. The arrangement of paragnaths resembles Nereis zonata Malmgren, 1867 (sensu Chambers & Garwood, 1992) described from Great Britain, but they differ mainly in the following key features: in N. arroyensis, posterodorsal tentacular cirri reach chaetiger 4, whereas in N. zonata they reach chaetiger 2; in N. arroyensis, the paragnaths of both bands in areas VII-VIII are of similar size, whereas in N. zonata paragnaths of the anterior band are larger; in N. arroyensis, dorsal ligules in anterior chaetigers are longer than median ligules, whereas in N. zonata they are subequal; in N. arroyensis, notopodial falcigers have dentate blades, whereas in N. zonata they are edentate.
Nereis largoensisTreadwell, 1931
Figure 3 Nereis largoensisTreadwell, 1931. Holotype AMNH 1987. A, Anterior end, dorsal view; B, posterior end, dorsal view; C, anterior end dissected showing pharynx, ventral view (arrows point cones at the lateral margins of areas VI). Scale bars: A-C, 3 mm.
Figure 4 Nereis largoensisTreadwell, 1931. Holotype AMNH 1987. A, Chaetiger 1, right parapodium; B, chaetiger 11, right parapodium; C, chaetiger 25, right parapodium; D, chaetiger 38, right parapodium; E, chaetiger 55, right parapodium; F, notopodial homogomph falciger, chaetiger 25; G, notopodial homogomph falciger, chaetiger 38; H, notopodial homogomph falciger, chaetiger 60; I, shaft of supra-acicular, heterogomph with short boss spiniger, chaetiger 60; J, shaft of sub-acicular, heterogomph with long boss spiniger, chaetiger 60; K, supra-acicular heterogomph falciger, chaetiger 60; L, sub-acicular heterogomph falciger, chaetiger 60. Scale bars: A-E, 0.25 mm; F-L, 10 µm.
Nereis brevicirrataTreadwell, 1929: 3-5, Figs.9-14 (preoccupied, non Nereis brevicirrata Treadwell, 1920).
Nereis largoensisTreadwell, 1931: 3 (replacement name).
Nereis pelagica largoensisHartman, 1956: 280.
Description. Holotype (AMNH 1987) in good conditions, complete, 82 mm long, 5.5 mm wide at chaetiger 10 excluding parapodia, 63 chaetigers. Body pale, pigmentation absent (Fig. 3A, B).
Prostomium subpyriform, 1.3x longer than wide; anterior region distally entire, oblong, as long as posterior region, dorsal groove present (Fig. 3A); anterolateral gap between antenna and palpophore as long as diameter of antennae (Fig. 3A). Antennae digitiform, not passing the palps, gap between antennae very small (Fig. 3A). Palpophores ovoid, swollen, 1.5x longer than wide, 1.2x longer than prostomium, subdistal transverse groove present (Fig. 3A). Palpostyles subconical with rounded tips (Fig. 3A). Eyes blackish, rounded, anterior and posterior pairs subequal, eyes diameter shorter than basal width of antennae, in trapezoidal arrangement, lenses small (Fig. 3A). Tentacular belt 2.5x longer than chaetiger 1, covering posterior pair of eyes, anterior dorsal margin convex (Fig. 3A). Tentacular cirri smooth, cirrophores cylindrical, cirrostyles cirriform, left ventral cirri missing; posterodorsal tentacular cirri reaching chaetiger 2 (Fig. 3A). Pharynx not everted, previously dissected, oral ring longer than maxillary one (Fig. 3C). Jaws broad, inner margin dentate with about 7-8 rounded teeth (Fig. 3C). Maxillary ring: I = 2 cones in vertical row; II = 15-16 paragnaths with polygonal bases; III = 9-10 paragnaths with polygonal bases (perhaps incomplete because dissection); IV = 37-38 paragnaths with polygonal bases (Fig. 3C). Oral ring: V = 1 cone; VI =5 central cones in round (right VI with a hard irregular plate), merged paragnaths absent; 1-1 cone at the lateral margins bordering areas VII-VIII; VII-VIII = a broad belt with about 126 paragnaths covering all ridge and furrow regions, number of bands and rows unclear (midventral region missing); large paragnaths with polygonal bases in ridge regions forming a row, remaining ones much shorter and conical (Fig. 3C). Furrow pattern of areas VI-V-VI, λ-shaped (Fig. 3C). Dorsal cirrus digitiform and basally attached to dorsal ligule in first 2 chaetigers, filiform and medially attached thereafter (Fig. 4A-E); twice longer than distal region of dorsal ligule in anteriormost chaetigers (Fig. 4A), 2.3x in anterior chaetigers (Fig. 4B), 3.2-4.0x in middle chaetigers (Fig. 4C, D), 5x in posterior chaetigers (Fig. 4E). Dorsal ligule subconical with distal region longer than proximal ones in anteriormost chaetigers, becoming shorter since chaetiger 10 (Fig. 4A-E). Distal region of dorsal ligule 0.6x length of median ligule in anterior chaetigers (Fig. 4B), 0.8-1.2x in middle chaetigers (Fig. 4C, D), as long as in posterior chaetigers (Fig. 4E). Median ligule rounded in anterior chaetigers, subconical or digitiform from anterior chaetigers (Fig. 4A-E); 2.4x longer than neuroacicular ligule in anterior chaetigers (Fig. 4B), 1.3-1.4x in middle chaetigers (Fig. 4C, D), 2.5x in posterior chaetigers (Fig. 4E). Neuroacicular ligule rounded throughout, superior and inferior lobes absent (Fig. 4A-E). Neuroacicular postchaetal lobe rounded, shorter than neuroacicular ligule throughout. Ventral ligule digitiform in anterior chaetigers, subconical with blunt tip since chaetiger 15 (Fig. 4A-E); 2.3x longer than neuroacicular ligule in anterior chaetigers (Fig. 4B), 1.0-1.2x in middle chaetigers (Fig. 4C, D), as long as in posterior chaetigers (Fig. 4E). Ventral cirrus digitiform and long in first chaetigers, filiform thereafter (Fig. 4A-E); 0.8x length of ventral ligule in anterior chaetigers (Fig. 4A), 1.3x longer in middle chaetigers (Fig. 4C, D), 1.5x in posterior chaetigers (Fig. 4E). Aciculae dark brown throughout, becoming thicker toward posterior chaetigers (Fig. 4A-E); notoaciculae absent in first 2 chaetigers (Fig. 4A-E). Most chaetae broken or blades detached. Notochaetae consisting of homogomph symmetrical spinigers and falcigers. Blade of spinigers with basal pectinate, coarse teeth, becoming minute toward distal end. Notopodial homogomph falciger with symmetrical rim of shaft, inner edge edentate, blade fusiform with blunt ends in middle chaetigers and becoming sharp in posterior chaetigers (Fig. 4F-H). Neurochaetae consisting of heterogomph spinigers with short bosses and heterogomph falcigers with long bosses in supra-acicular fascicles, heterogomph spinigers and falcigers with long bosses in infra-acicular fascicles. Blade of spinigers with basal pectinate, coarse teeth, becoming minute toward distal end (Fig. 4I, J). Blades of falcigers falcate, pointed tips, with narrow teeth, infra-acicular ones with more teeth than supra-acicular ones (Fig. 4K, L).
Pygidium swollen, crenulated, wider than long (Fig. 3B); anal cirri missing (Fig. 3B).
Taxonomic summary
Material examined. Holotype of Nereis brevicirrata Treadwell AMNH 1987, Key Largo, Florida, no date, Coll. W Beebe.
Remarks
Hartman (1956) thought Nereis largoensis was similar to Nereis pelagica Linnaeus, 1758 and regarded it as a subspecies. Since a recent redescription of this supposed cosmopolitan species is not available, here the description by Chambers and Garwood (1992), and a specimen from England (ECOSUR P2840), were used for comparison. Nereis largoensis differs from N. pelagica in the following key features: in N. largoensis, the pharyngeal area V has paragnaths, which are lacking in N. pelagica; in N. largoensis, merged paragnaths in pharyngeal areas IV are absent, which are present in N. pelagica; in N. largoensis, the median ligules are longer than neuroacicular ligules in anterior chaetigers, whereas in N. pelagica they are subequal; in N. largoensis, the ventral ligules are longer than neuroacicular ligules in anterior and middle chaetigers, whereas in N. pelagica they are shorter or subequal; in N. largoensis, ventral cirri are longer than ventral ligules in posterior chaetigers, whereas in N. pelagica they are subequal.
Hartman (1956) separated Nereis largoensis from N. occidentalis by the shape of the blades of notopodial falcigers, here additional features are added: in N. occidentalis, the tentacular belt is slightly longer than chaetiger 1, whereas in N. largoensis it is 2.5 times longer than; in N. occidentalis, longest tentacular cirri reach chaetigers 7-8, whereas in N. largoensis they reach chaetiger 2; N. occidentalis has 2 bands of conical paragnaths, whereas N. largoensis has a wide band with several paragnaths; in N. occidentalis, ventral cirri are shorter than ventral ligules throughout, whereas in N. largoensis they are longer than in posterior chaetigers; in N. occidentalis, the blades of the notopodial homogomph falcigers are falcate with a distinct tendon and inner margin fully dentate, whereas in N. largoensis the blades are fusiform without a tendon and the margins are smooth. Therefore, Nereis largoensis is regarded as a valid species and different from its similar species N. pelagica and N. occidentalis.
Warren (1942) introduced the name Nereis gracilicirrata for material collected in Grand Isle, Louisiana, USA, but the description is so general that it is even difficult to ascertain the genus of the species, and the type material was not deposited. Hartman (1954, 1956) concluded that N. gracilicirrata is a synonym of N. largoensis, and Pettibone (1956) examined material from Grand Isle previously identified as N. largoensis by Behre (1950) and concluded they are N. occidentalis instead. However, after the very general description, it is not possible to assure such specimens are N. gracilicirrata and no other nereidid, so here N. gracilicirrata is considered to be an indeterminable species, and not a synonym of N. largoensis.
Genus Perinereis Kinberg, 1865
Type species. Perinereis novaehollandiae Kinberg, 1865, by subsequent designation (Hartman, 1948).
Diagnosis followed: Bakken and Wilson, 2005.
Perinereis diversidentataTreadwell, 1943
Figure 5 Pseudonereis diversidentata (Treadwell, 1943) n. comb. Holotype of Perinereis diversidentata AMNH 3235. A, Whole specimen, dorsal view; B, anterior end, dorsal view; C, posterior end, dorsal view; D, pharynx, dorsal view (arrows point cones at the lateral margins of areas VI); E, anterior end, ventral view (arrows point caecal glands). Scale bars: A, 4 mm; B-E, 2 mm.
Figure 6 Pseudonereis diversidentata (Treadwell, 1943) n. comb. Holotype of Perinereis diversidentata AMNH 3235. A, Chaetiger 2, right parapodium, posterior view; B, chaetiger 11, right parapodium, posterior view; C, chaetiger 26, right parapodium, posterior view; D, chaetiger 44, right parapodium, posterior view; E, chaetiger 71, right parapodium, posterior view; F, left jaw, dorsal view; G, supra-acicular heterogomph falciger, chaetiger 44; H, sub-acicular heterogomph falciger, chaetiger 2; I, sub-acicular heterogomph falciger, chaetiger 11; J, sub-acicular heterogomph falciger, chaetiger 44. Scale bars: A-E, 0.25 mm; F, 0.1 mm; G-J, 10 µm.
Perinereis diversidentataTreadwell, 1943: 1-2, Figs.1-7.
Pseudonereis variegataDay, 1953: 425-426 (partim, record only). Hartman, 1956: 281-282 (non Grube & Kröyer in Grube, 1857).
Description. Holotype (AMNH 3235) incomplete, body with soft tissue but in good conditions, previously dissected, pharynx damaged and incomplete (Fig. 5D, E), 140 mm long, 7 mm wide at chaetiger 10 excluding parapodia, 72 chaetigers (Fig. 5A). Body pale, pigmentation absent (Fig. 5A-C).
Prostomium subpyriform, as long as wide; anterior region distally entire, oblong, as long as posterior region, dorsal groove present (Fig. 5B); anterolateral gap between antenna and palpophore as long as diameter of antennae (Fig. 5B). Antennae subconical, not passing the palps, gap between them very small (Fig. 5B). Palpophores ovoid, swollen, 1.2x longer than wide, 0.8x length of prostomium, subdistal transverse groove present (Fig. 5B). Palpostyles subpyriform (Fig. 5B). Eyes blackish, rounded, anterior and posterior pairs subequal, eyes diameter half as long as antennae basal width, in trapezoidal arrangement, anterior pair placed on the dorsolateral margins of prostomium, lenses not visible, nuchal organs visible (Fig. 5B). Tentacular belt 1.3x longer than chaetiger 1, not covering posterior pair of eyes, anterior dorsal margin straight (Fig. 5B). Tentacular cirri smooth, cirrophores ring-shaped, cirrostyles cirriform; posterodorsal tentacular cirri reaching chaetiger 2 (Fig. 5B). Pharynx previously dissected, damaged, oral ring 1.6x longer than maxillary one (Fig. 5D). Jaws broad, inner margin with 7-8 rounded teeth (Fig. 6F). Maxillary ring: I = 1 cone; II = 14-16 cones in triangle; III = 27 cones in 4 rows (perhaps area incomplete); IV = 27-30 cones in 6 -7 rows (perhaps areas incomplete), merged paragnaths absent. Oral ring: V = 0; VI = 1-1 central shield-shaped paragnaths, 1-1 cone at the lateral margins bordering areas VII-VIII; VII -VIII = anterior band with 1 furrow row with 8 cones and a ridge row with 10 cones; posterior band with 1 furrow region with 8 cones and a ridge row with 13 cones; furrow and ridge regions with 1 or 2 paragnaths each, perhaps midventral area incomplete (Fig. 5D, E). Furrow pattern of areas VI-V- VI, Π-shaped (Fig. 5D). Caecal glands present (Fig. 5E) . Dorsal cirrus digitiform in first 2 chaetigers, subconical with blunt tip thereafter, attached basally to dorsal ligule in anteriormost chaetigers, medially in middle chaetigers, subdistally in posterior chaetigers (Fig. 6A- E); 1.6x longer than tip of distal region of dorsal ligule in anteriormost chaetigers (Fig. 6A), 3x in anterior and middle chaetigers (Fig. 6B-D), 2.5x in posterior chaetigers (Fig. 6E); 3.2x longer than proximal region of dorsal ligule in anteriormost chaetigers (Fig. 6A), 1.3-1.5x in anterior chaetigers (Fig. 6B), as long as in middle chaetigers (Fig. 6C, D), 0.4x length in posterior chaetigers (Fig. 6E). Dorsal ligule rounded in anterior chaetigers, becoming subcylindrical in middle chaetigers, and pennant-like in posterior chaetigers, with distal regions shorter than proximal ones throughout (Fig. 6A-E) . Distal region of dorsal ligule as long as median ligule in anterior chaetigers (Fig. 6B), 2.0-2.2x in middle chaetigers (Fig. 6C, D), 3.8x in posterior chaetigers (Fig. 6E). Median ligule rounded in anterior chaetigers, digitiform thereafter; 2.5x longer than neuroacicular ligule in anterior chaetigers (Fig. 6B), 1.5x in middle and posterior chaetigers (Fig. 6C-E). Neuroacicular ligule subconical throughout (Fig. 6A-E); superior and inferior lobes present in anterior and middle chaetigers, both rounded, inferior one slightly longer than superior one throughout (Fig. 6A-E). Neuropodial postchaetal lobes rounded, lamelliform, half as long as neuroacicular ligule throughout (Fig. 6A-E). Ventral ligule subconical with blunt tip in anterior chaetigers, digitiform thereafter (Fig. 6A-E); as long as neuroacicular ligule throughout (Fig. 6A-E). Ventral cirrus digitiform in first chaetigers, subconical thereafter (Fig. 6A-E); as long as ventral ligule in anteriormost chaetigers (Fig. 6A), 0.7x length in anterior and middle chaetigers (Fig. 6B-D), half as long as in posterior chaetigers (Fig. 6E). Aciculae dark brown and neuroaciculae almost twice thicker than notoaciculae throughout (Fig. 6A-E); notoaciculae absent in first 2 chaetigers (Fig. 6A). Notochaetae consisting of homogomph symmetrical spinigers throughout, decreasing in number toward posterior chaetigers (Fig. 6A-E). Neurochaetae consisting of homogomph symmetrical spinigers and heterogomph falcigers in supra-acicular fascicles, heterogomph spinigers and falcigers in infra-acicular fascicles. Blades of heterogomph falcigers in both fascicles falcate, blades decreasing their size toward posterior chaetigers, narrow teeth, a half of the inner edge edentate (Fig. 6G-J).
Pygidium missing (Fig. 5C).
Taxonomic summary
Material examined. Holotype of Perinereis diversidentata AMNH 3235, Cape Cross, Namibia, Africa, 11 September 1925, Coll. H Lang & R Boulton.
Remarks
The current description agrees well with the original one, some features were added as the presence of the caecal glands, illustrations of the pharynx, the presence of both neuropodial superior and inferior lobes in anterior and middle chaetigers, and the description of posteriormost chaetigers. Treadwell (1943, Fig. 5) described a distorted parapodium from chaetiger 50 (aciculae are overlapped) perhaps because he misplaced the parapodium in the slide and the tissue of the parapodium from such region is delicate, so he described neuroacicular ligules broad and ventral cirri longer than ventral ligules, but neuroacicular ligules are narrower and ventral cirri are shorter than throughout the body. Treadwell (1943) mentioned the poor state of the pharynx when examined the specimens, suggesting previous damage.
Day (1953) examined type material of Perinereis diversidentata and considered it was a junior synonym of Pseudonereis variegata (Grube & Kröyer in Grube, 1857), although he highlighted differences in the arrangement of paragnaths in the maxillary ring. Hartman (1956) agreed with Day’s decision. However, both species can be separated based on the following key differences (sensu Conde-Vela, 2018): P. diversidentata has a straight anterior margin of the tentacular belt, whereas in P. variegata it is convex; P. diversidentata lacks paragnaths in area V and has shield-shaped paragnaths in central areas VI and cones in lateral areas VI, whereas P. variegata has paragnaths in area V and has crescent-shaped paragnaths in central areas VI only; in P. diversidentata, ventral ligules are subequal than neuroacicular ligules throughout, whereas in P. variegata they are shorter throughout; in P. diversidentata, dorsal cirri are relatively shorter in middle and posterior chaetigers than in P. variegata.
Moreover, a crucial difference between Perinereis diversidentata and P. variegata is the lack of p-bars arranged in comb-like rows in the former species, which is a key feature to separate Pseudonereis species from Perinereis (Villalobos-Guerrero et al., 2021). Therefore, here the original combination Perinereis diversidentata is used. This difference also separates P. diversidentata from the similar species Pseudonereis podocirra (Schmarda, 1861) (type locality: Cape of Good Hope, South Africa). Based on the Perinereis groups proposed by Hutchings et al. (1991), P. diversidentata belongs to the group 1B (areas VI with a single bar and dorsal ligules greatly expanded on posterior chaetigers). Some Perinereis species from the Eastern Atlantic coasts are P. atlantica (McIntosh, 1885) (type locality: Cape Verde Islands), P. capensis (Kinberg, 1865) (type locality: Cape of Good Hope, South Africa), P. falsovariegataMonro, 1933 (type locality: Preekstoel, South Africa), P. majungaensis Fauvel, 1921 (type locality: Madagascar), and P. namibia Wilson & Glasby, 1993 (type locality: Lüderitz, Namibia), but none of them belong to group 1B. Overlooking the differences in parapodial features, P. diversidentata differs mainly from P. namibia in having a single bar in areas VI rather than several bars in a row, and P. diversidentata differs from P. capensis (fide Monro, 1933) in having a single cone on the lateral margins of each area VI.
Pseudonereis palpata (Treadwell, 1923)
Figure 7 Pseudonereis palpata (Treadwell, 1923). Paratype of Nereis (Neanthes) palpata USNM 19031. A, Anterior end, dorsal view; B, posterior end, dorsal view; C, chaetiger 14, right parapodium, anterior view; D, chaetiger 70, right parapodium, anterior view; E, pharynx, ventral view; F, same, dorsal view; G, jaws, dorsal view; H, sub-acicular heterogomph falciger, chaetiger 70; I, supra-acicular heterogomph falciger (left) and homogomph spinigers (right), chaetiger 70. Scale bars: A, B, E, F, 2 mm; C-D, G, 0.4 mm; H, I, 10 µm.
Figure 8 Pseudonereis palpata (Treadwell, 1923). Holotype of Nereis disparsetosa Treadwell USNM 19638. A, Anterior end, dorsal view; B, posterior end, dorsal view; C, pharynx, dorsal view; D, same, ventral view; E, jaws, dorsal view. Scale bars: A, 1 mm; B- E, 0.5 mm.
Figure 9 Pseudonereis palpata (Treadwell, 1923). Holotype of Nereis disparsetosa Treadwell USNM 19638. A, Chaetiger 1, right parapodium, anterior view; B, chaetiger 12, right parapodium, anterior view; C, chaetiger 31, right parapodium, anterior view; D, chaetiger 65, right parapodium, anterior view; E, supra-acicular heterogomph falciger, chaetiger 31; F, sub-acicular heterogomph falciger, chaetiger 12; G, sub-acicular heterogomph falciger, chaetiger 31. Scale bars: A-D, 2 mm; E-G, 10 µm.
Nereis (Neanthes) palpataTreadwell, 1923: 5-9, Figs. 6-15.
Pseudonereis palpataHartman, 1956: 255, 256, 264, 267 (list only). Bakken, 2007: 163-164, Figs.10A-C.
Nereis disparsetosaTreadwell, 1932: 13-15, Figs.1-5.
Description of paratype of Nereis (Neanthes) palpata. Paratype (USNM 19031) incomplete, in fair conditions, 85 mm long, 3.5 mm wide at chaetiger 10 excluding parapodia, 70 chaetigers. Body pale, pigmentation absent, whitish glandular masses in parapodia of anterior and middle chaetigers, whitish in posterior chaetigers (Fig. 7A, B).
Prostomium subpyriform, as long as wide; anterior region distally entire, oblong, shorter than posterior region, dorsal groove present (Fig. 7A); anterolateral gap between antenna and palpophore half as long as diameter of antennae (Fig. 7A). Antennae subconical, not passing the palps, gap between them inconspicuous (Fig. 7A). Palpophores subcylindrical, 1.2x longer than wide, as long as prostomium, subdistal transverse groove absent (Fig. 7A). Palpostyles rounded (Fig. 7A). Eyes blackish, rounded, anterior pair slightly larger than posterior one, eyes diameter as long as antennae basal width, in trapezoidal arrangement, lenses not visible (Fig. 7A). Tentacular belt as long as chaetiger 1, not covering posterior pair of eyes, anterior dorsal margin straight (Fig. 7A). Tentacular cirri smooth, cirrophores ring-shaped, cirrostyles cirriform; posterodorsal tentacular cirri reaching chaetiger 5 (Fig. 7A). Pharynx everted in both specimens, oral ring 1.5x longer than maxillary one (Fig. 7E, F.). Jaws broad, inner margin with 8-10 rounded teeth (Fig. 7G). Maxillary ring: I = 1 cone; II = 41 p-bars arranged in 4 rows in triangle; III = 105 p-bars arranged in 4 rows in triangle; IV = 125-132 paragnaths in a sigmoidal patch, 84-86 p-bars arranged in 5 rows, 32-37 cones and 9 merged paragnaths arranged in arc. Oral ring: V = 1 cone; VI = 1-1 central shield-shaped paragnath with a cone on the right region; VII-VIII = anterior band with 1 furrow row with 12 p-bars and a ridge row with 9 cones in a single band, rows vertically displaced; furrow and ridge regions with 1 paragnath each (Fig. 7E, F). Furrow pattern of areas VI-V-VI, Π-shaped (Fig. 7F). Caecal glands not seen because the poor state of the specimen. Dorsal cirrus digitiform in first chaetigers, filiform in anterior, middle and posterior chaetigers, digitiform in posteriormost chaetigers, attached basally to dorsal ligule in anteriormost chaetigers, medially in anterior chaetigers, subdistally in middle and posterior chaetigers (Fig. 7C, D); 3.5x longer than tip of distal region of dorsal ligule in anterior chaetigers (Fig. 7C), 5.4x in posterior chaetigers (Fig. 7D); 2.7x longer than proximal region of dorsal ligule in anterior chaetigers (Fig. 7C), 0.3x in posterior chaetigers (Fig. 7D). Dorsal ligule subconical with rounded, broad tips in anterior chaetigers, becoming subcylindrical in middle chaetigers, and oblong in posterior chaetigers, with distal regions shorter than proximal ones throughout (Fig. 7C, D); distal region of dorsal ligule as long as median ligule in anterior chaetigers (Fig. 7C), 4.8x longer in posterior chaetigers (Fig. 7D). Median ligule rounded in in anterior chaetigers, digitiform thereafter; as long as neuroacicular ligule in anterior chaetigers (Fig. 7C), 3x longer in posterior chaetigers (Fig. 7D). Neuroacicular ligule subconical throughout (Fig. 7C, D); superior and inferior lobes present in anterior and middle chaetigers, both rounded, inferior one slightly longer than superior one throughout (Fig. 7C, D). Neuropodial postchaetal lobes rounded, lamelliform, half as long as neuroacicular ligule throughout. Ventral ligule rounded in anterior chaetigers, digitiform thereafter (Fig. 7C, D); half as long as neuroacicular ligule in anterior chaetigers (Fig. 7C), 0.3x length in posterior chaetigers (Fig. 7D). Ventral cirrus digitiform and broad in first chaetigers, narrower thereafter (Fig. 7C, D); 0.8x length of ventral ligule in anterior chaetigers (Fig. 7C), 0.7x in posterior chaetigers (Fig. 7D). Aciculae dark brown throughout (Fig. 7C, D); notoaciculae absent in first 2 chaetigers (Fig. 9A); neuroaciculae becoming thicker than notoaciculae toward posterior chaetigers. Notochaetae consisting of homogomph symmetrical spinigers throughout, decreasing in number toward posterior chaetigers (Fig. 7C, D). Neurochaetae consisting of homogomph symmetrical spinigers and heterogomph falcigers in supra-acicular fascicles, heterogomph spinigers and falcigers in infra-acicular fascicles (Fig. 7H, I). Heterogomph spinigers present from chaetiger 22. Blades of supra-acicular spinigers pectinate, teeth minute, decreasing in size toward distal end (Fig. 7I). Blades of heterogomph falcigers in both fascicles falcate, blades decreasing their size toward posterior chaetigers, narrow teeth, 2 third of the inner edge edentate (Fig. 7H, I).
Pygidium missing (Fig. 7B).
Description of syntypes of Nereis disparsetosa. Syntypes (USNM 19638) consisted in 2 specimens in excellent conditions, one selected for description, 32 mm long, 2.2 mm wide at chaetiger 10 excluding parapodia, 68 chaetigers. Body pale, pigmentation absent, whitish glandular masses in parapodia of anterior and middle chaetigers, orangish in posterior chaetigers (Fig. 8A, B).
Prostomium subpyriform, as long as wide; anterior region distally entire, oblong, shorter than posterior region, dorsal groove present (Fig. 8A); anterolateral gap between antenna and palpophore half as long as diameter of antennae (Fig. 8A). Antennae subconical, not passing the palps, gap between them inconspicuous (Fig. 8A). Palpophores subcylindrical, 1.2x longer than wide, as long as prostomium, subdistal transverse groove absent (Fig. 8A). Palpostyles rounded (Fig. 8A). Eyes blackish, rounded, anterior pair slightly larger than posterior one, eyes diameter as long as antennae basal width, in trapezoidal arrangement, lenses not visible (Fig. 8A). Tentacular belt as long as chaetiger 1, not covering posterior pair of eyes, anterior dorsal margin straight (Fig. 8A). Tentacular cirrismooth, cirrophores ring-shaped, cirrostyles cirriform; posterodorsal tentacular cirri reaching chaetiger 5 (Fig. 8A). Pharynx everted, oral ring as long as maxillary one (Fig. 8C, D). Jaws broad, inner margin with 8-10 rounded teeth (Fig. 8E). Maxillary ring: I = 0; II = 27-28 p-bars arranged in 3-4 rows in triangle; III = 67 p-bars arranged in 4 rows in triangle; IV = 81-94 paragnaths in a sigmoidal patch, 45-56 p-bars arranged in 5-6 rows, 31-32 cones and 5-6 merged paragnaths arranged in arc. Oral ring: V = 1; VI = 1-1 central smooth bar; VII-VIII = anterior band with 1 furrow row with 12 p-bars and a ridge row with 9 cones in a single band, rows vertically displaced; furrow and ridge regions with 1 paragnath each (Fig. 8C, D). Furrow pattern of areas VI-V-VI, Π-shaped (Fig. 8C). Dorsal cirrus digitiform in first chaetigers, filiform in anterior, middle and posterior chaetigers, digitiform in posteriormost chaetigers, attached basally to dorsal ligule in anteriormost chaetigers, medially in anterior chaetigers, subdistally in middle and posterior chaetigers, distally in posteriormost chaetigers (Fig. 9A-D); 3.2x longer than tip of distal region of dorsal ligule in anteriormost chaetigers (Fig. 9A), 3.5x in anterior chaetigers (Fig. 9B), 5x in middle chaetigers (Fig. 9C), 11x in posterior chaetigers (Fig. 9D); 3.2x longer than proximal region of dorsal ligule in anteriormost chaetigers (Fig. 9A), 2.7x in anterior chaetigers (Fig. 9B), 1.2x in middle chaetigers (Fig. 9C), 0.3x length in posterior chaetigers (Fig. 9D). Dorsal ligule subconical with rounded, broad tips in anterior chaetigers, becoming subcylindrical in middle chaetigers, and oblong in posterior chaetigers, with distal regions shorter than proximal ones throughout (Fig. 9A-D); distal region of dorsal ligule as long as median ligule in anterior chaetigers (Fig. 9B), 2x longer in middle chaetigers (Fig. 9C), 3.4x in posterior chaetigers (Fig. 9D). Median ligule rounded in in anterior chaetigers, digitiform thereafter; as long as neuroacicular ligule in anterior chaetigers (Fig. 9B), 1.5x longer in middle chaetiger 31 (Fig. 9C), 2.7x in posterior chaetigers (Fig. 9D). Neuroacicular ligule subconical throughout (Fig. 9A-D); superior and inferior lobes present in anterior and middle chaetigers, both rounded, inferior one slightly longer than superior one throughout (Fig. 9A-D). Neuropodial postchaetal lobes rounded, lamelliform, half as long as neuroacicular ligule throughout. Ventral ligule rounded in anterior chaetigers, digitiform thereafter (Fig. 9A-D); twice longer than neuroacicular ligule in anteriormost chaetigers (Fig. 9A), half as long as in anterior and middle chaetigers (Fig. 9B, C), 0.3x length in posterior chaetigers (Fig. 9D). Ventral cirrus digitiform and broad in first chaetigers, narrower thereafter (Fig. 9A-D); 0.8x length of ventral ligule in anterior chaetigers (Fig. 9A, B), 0.7x in middle and posterior chaetigers (Fig. 9C, D). Aciculae dark brown throughout (Fig. 9A-D); notoaciculae absent in first 2 chaetigers (Fig. 9A); neuroaciculae becoming thicker than notoaciculae toward posterior chaetigers. Notochaetae consisting of homogomph symmetrical spinigers throughout, decreasing in number toward posterior chaetigers (Fig. 9A-D). Neurochaetae consisting of homogomph symmetrical spinigers and heterogomph falcigers in supra-acicular fascicles, heterogomph spinigers and falcigers in infra-acicular fascicles (Fig. 9E-G). Heterogomph spinigers present from about chaetiger 30. Blades of supra-acicular spinigers pectinate, teeth minute, decreasing in size toward distal end. Blades of heterogomph falcigers in both fascicles falcate, blades decreasing their size toward posterior chaetigers, narrow teeth, two third of the inner edge edentate (Fig. 9E-G).
Pygidium swollen, as long as wide (Fig. 8B); anal cirri cirriform, as long as pygidium (Fig. 8B).
Taxonomic summary
Material examined. Paratype of Nereis (Neanthes) palpata USNM 19031 (1), Ilha de Alcatrazes, São Paulo, Brazil, Coll. H Leuderwaldt (2 specimens in the vial, one is a Perinereis in bad conditions, disposed separately in a vial and labeled as Perinereis sp.). Syntypes of Nereis disparsetosa USNM 19638 (2), Villa Bella, Ilha de São Sebastião, São Paulo, Brazil, Coll. H Leuderwaldt, 1925.
Remarks
The current description matches with the original one in most features (Treadwell, 1923; 1932), but some differences are detailed below. Treadwell (1923) detailed for P. palpata the presence of brownish pigmentation in prostomium, palps, tentacular belt, and dorsum of chaetigers up to the posterior end of the body, but the paratype examined lacked such pigments. Also, the author described edentate jaws, but teeth are present, although they are almost wholly ensheathed. Treadwell (1932, Fig. 4) detailed the presence of heterogomph falcigers in the notopodia, but they were not found in the types specimens examined, and after the illustration clearly describes typical neuropodial heterogomph falcigers in Pseudonereis species, so the discrepancy is attributed to confusion in the words.
Treadwell originally placed Nereis palpata in the subgenus Neanthes after the presence of paragnaths in all pharyngeal areas, but Hartman (1938) transferred it to Pseudonereis, and believed Nereis disparsetosa and Pseudonereis atopodon Chamberlin, 1919 (type locality: Nomuka, Tonga) were synonyms of it. After the examination of the type material of Nereis palpata and N. disparsetosa, the synonymy of the latter is retained after no relevant differences were found between them. Curiously, the type localities from both species are very near each other, but Treadwell overlooked this fact and failed in comparing N. disparsetosa with his previous species N. palpata. Pseudonereis palpata differs from P. atopodon in the following key features (sensu Bakken 2007): in P. palpata, median ligules are subequal to slightly longer than neuroacicular ligules in anterior chaetigers and longer than in middle chaetigers, whereas in P. atopodon they are shorter than in such chaetigers; in P. palpata, dorsal ligules are much broader and larger in chaetiger 30 than in P. atopodon in such chaetiger; in P. palpata, the distal region of dorsal ligules are twice longer than median ligules in chaetiger 30, whereas in P. atopodon they as subequal; in P. palpata, dorsal ligules in posteriormost chaetigers become very broad, with a high convex dorsal surface, and up to 5x longer than median ligules, whereas in P. atopodon they are less broad, lack a convex dorsal surface, and are 2.5x longer than median ligules.
Discussion
Three of the 4 species examined here were regarded as valid species. To facilitate future studies of Nereididae described by Treadwell, they are summarized in the Table 1 with additional comments. Of the 34 nereidid names proposed by Treadwell, 2 are replacement names, 16 are junior synonyms of other, 6 are valid and retain their original combination, and 10 are valid but they were transferred to another genus (Table 1).
Table 1 Original nereidid names proposed by Treadwell from 1901 to 1943 (excepting Leptonereis maculata, see below), including their current status. Names are sorted first by year and later alphabetically.
| Original name | Type locality | Current combination or synonymy | Type locality of senior synonym (if apply) | Observations |
|---|---|---|---|---|
| Nereis arroyensis | Arroyo, Puerto Rico | Nereis arroyensis | -- | Regarded as valid species by Hartman (1956), redescribed here and retained as valid species. |
| Treadwell, 1901 | Treadwell, 1901 | |||
| Nereis notomacula Treadwell, 1914 | San Francisco Bay, California, USA | Platynereis bicanaliculata (Baird, 1863) | Vancouver Island, Canada. | Hartman (1936) proposed N. notomacula and Uncinereis subita are synonyms of U. agassizi (Ehlers, 1868). After, Hartman (1951) proposed the synonymy with P. bicanaliculata without further comments, requiring examination of types to reassess its status. |
| Nereis (Platynereis) integer Treadwell, 1920 | Romblon, Philippines | Platynereis polyscalma Chamberlin, 1919 | Ellice Island, Tuvalu. | Hartman (1938) synonymized the species without further explanation. Examination of type material is needed to reassess its status. |
| Nereis brevicirrata Treadwell, 1920 | Santos, Brazil | Perinereis brevicirrata (Treadwell, 1920) | -- | Hartman (1938) transferred this species to Perinereis Kinberg, 1865 based on the pharyngeal arrangement and kind of paragnaths. Belonging to P. aibuhitensis (Grube, 1878) species group fide Villalobos-Guerrero et al. (2021). |
| Nereis (Ceratonereis) alaskensis Treadwell, 1921 | Valdez Harbor, Alaska | Composetia paucidentata (Moore, 1903) | Aleutian Islands, Bering Sea. | Hartman (1938) synonymized the species without further explanation. Revision of type material is needed to reassess its status. |
| Nereis (Leptonereis) acutaTreadwell, 1923 | Santos, Brazil | Laeonereis acuta (Treadwell, 1923) | -- | Hartman (1956) and later Pettibone (1971) synonymized it with Laeonereis culveri (Webster, 1879), but some authors regarded them as distinct. Conde-Vela (2021a) regarded L. acuta as valid after the examination of type material. |
| Nereis (Neanthes) australisTreadwell, 1923 | Maldonado, Uruguay | Alitta succinea (Leuckart, 1847) | Helgoland, Germany. | Villalobos-Guerrero and Carrera-Parra (2015) highlighted this and other species are in need of further revision to reassess its synonymy with A. succinea. |
| Nereis (Neanthes) palpataTreadwell, 1923 | São Paulo, Brazil | Pseudonereis palpata (Treadwell, 1923) | -- | Bakken (2007) redescribed the species. Here is retained as valid species and includes N. disparsetosaTreadwell, 1932. |
| Leptonereis egregicirrata Treadwell, 1924 | Antigua Island, Antigua and Barbuda | Neanthes egregicirrata (Treadwell, 1924) | -- | Hartman (1956) regarded it as questionable and Pettibone (1956) redescribed it and regarded as valid. De León-González et al. (1999) transferred it to Neanthes Kinberg, 1865. Since Neanthes species exhibit several epitokal patterns (Villalobos-Guerrero & Idris, 2021), further revisions of this and other species in the genus are needed. |
| Namonereis (sic) kartaboensis Treadwell, 1926 | Kartabo Point, Guyana | Namalycastis kartaboensis(Treadwell, 1926) | -- | Glasby (1999) redescribed and transferred it to Namalycastis Hartman, 1959 based on material from Surinam because type material is dried out. |
| Leptonereis maculata (Kinberg, 1865) sensu Treadwell (1928) (combination proposed for Nicon maculata Kinberg, 1865) | Galapagos Islands, Ecuador (not type locality of N. maculata) | Rullierinereis mexicana (Treadwell, 1942) | Topolobampo Bay, Mexico. | Treadwell (1928) examined several epitokes collected in the Arcturus Expedition, and following Grube (1878), he transferred Nicon maculata to Leptonereis Kinberg, 1865, instead of proposing the new name L. maculata as Hartman (1956) suggested. Pettibone (1971) identified the Arcturus Expedition specimens as Rullierinereis mexicana (Treadwell, 1942), but needs to be re-assessed to ensure they belong to the same species. |
| Neanthes obscuraTreadwell, 1928 | Off Cocos Island, Costa Rica | Perinereis helleri (Grube, 1878) | Bohol Island, Philippines. | Hartman (1956) regarded this species as a typical representative of Perinereis helleri. Hutchings et al. (1991) redescribed P. helleri but overlooked this synonymy, so further revision is needed. |
| Uncinereis luteaTreadwell, 1928 | Sargassum Sea, Atlantic Ocean | Platynereis dumerilii (Audouin & Milne-Edwards, 1833) | La Rochelle, France. | Hartman (1951) synonymized the species with P. dumerilii without further explanation. Species similar to Platynereis mucronata de León-González et al., 2001. |
| Ceratonereis singularisTreadwell, 1929 | Gulf of California, Mexico | Ceratonereis singularisTreadwell, 1929 | -- | Perkins (1980) redescribed this species but regarded it as amphiamerican. Conde-Vela (2021b) redescribed the species and restrict its distribution to the Tropical Eastern Pacific. |
| Nereis spiniferaTreadwell, 1929 | Puget Sound, Washington, USA | Perinereis monterea (Chamberlin, 1918) | Monterey Bay, California, USA. | Hartman (1936) transferred Nereis (Neanthes) monterea to Perinereis and later Hartman (1940) regarded N. spinifera as its junior synonym. Examination of type material is needed to reassess the synonymy. |
| Nereis heterocirrataTreadwell, 1931 | Takami Island, Japan | Nereis heterocirrataTreadwell, 1931 | -- | Imajima and Hartman (1964) noted it is similar to Nereis pelagica. Imajima (1972) added illustrations of the pharynx, parapodia, and chaetae, of both atokes and epitokes. |
| Nereis largoensisTreadwell, 1931 (replacement name for Nereis brevicirrataTreadwell, 1929) | Key Largo, Florida | Nereis largoensisTreadwell, 1931 | -- | Hartman (1956) regarded N. largoensis as a subspecies of N. pelagica. Here the former species is redescribed and distinguished from N. pelagica. |
| Nereis decoraTreadwell, 1932 | São Paulo, Brazil | Nereis riisei Grube & Ørsted in Grube, 1857 | Saint Croix, US Virgin Islands | Hartman (1956) synonymized this species with N. riisei without further explanation, requiring examination of type material to reassess its status. |
| Nereis disparsetosaTreadwell, 1932 | Pseudonereis palpata(Treadwell, 1923) | Hartman (1938) proposed this synonymy without further comments. Here the synonymy is retained after the examination of type material. | ||
| Nereis (Leptonereis) distorta Treadwell, 1936 | Xiamen, China | Tylorrhynchus heterochetus (de Quatrefages, 1866) | Shanghai, China. | Pettibone (1971) examined the type material and synonymized it with T. heterochetus. Recently, Xing-Han et al. (2020) found at least 3 genetic geographic lineages of T. heterochetus are present in the China Seas, so further revision is needed to reassess its status. |
| Nereis (Neanthes) amoyensis Treadwell, 1936 | Xiamen, China | Nereis amoyensis Treadwell, 1936 | Yellow Sea, China. | Hartman (1956) transferred it to Nereis because the presence of notopodial homogomph falcigers. Sun and Yang (2004) subjectively regarded it as a junior synonym of Nereis longior Khlebovich &Wu, 1962 from the Yellow Sea. However, Treadwell’s name has priority (ICZN 1999, Art. 23), so N. longior becomes a junior synonym of N. amoyensis. |
| Nereis (Neanthes) orientalis Treadwell, 1936 | Xiamen, China | Perinereis línea (Treadwell, 1936) | Xiamen, China. | Arias et al. (2013) made a taxonomic summary of P. linea, and suggested N. (Neanthes) orientalis as its synonym. Villalobos-Guerrero et al. (2021) redescribed the types of both species and confirmed the synonymy. |
| Nereis (Perinereis) linea Treadwell, 1936 | Xiamen, China | Perinereis línea (Treadwell, 1936) | -- | Villalobos-Guerrero et al. (2021) redescribed and retained this species as valid. |
| Nereis (Ceratonereis) bartletti Treadwell, 1937 | Off Greenland, Denmark | Composetia hircinicola (Eisig, 1870) | Balearic Islands, Spain. | Hartman (1938) synonymized this species with C. hircinicola. Villalobos-Guerrero et al. (2022) overlooked this species in their review of Composetia. Further revision is needed to ensure they are identical. |
| Nereis ambiguus Treadwell, 1937 | Islas Revillagigedo, Mexico | Nereis ambigua Treadwell, 1940 | -- | Hartman (1956) synonymized it with Nereis riisei. Salazar-Vallejo et al. (2021) proposed fixing the declination of the original specific name and regarded it as a valid species. |
| Uncinereis trimaculosa Treadwell, 1940 | Galveston, Texas, USA | Platynereis dumerilii (Audouin & Milne-Edwards, 1833) | La Rochelle, France. | Hartman (1951) synonymized the species with P. dumerilii without further explanation. Species similar to Platynereis mucronata de León-González, Solís-Weiss & Valadez-Rocha, 2001. |
| Leptonereis nota Treadwell, 1941 | Galveston, Texas, USA | Laeonereis nota (Treadwell, 1941) | -- | Hartman (1956) and Pettibone (1971) considered the species as synonym of Laeonereis culveri (Webster, 1879). However, Conde-Vela (2021a) retained L. nota as valid species after the examination of type material. |
| Nereis (Neanthes) varia Treadwell, 1941 (replacement name for Nereis (Neanthes) paucidentataTreadwell, 1939) | Charlestown, Massachusetts, USA | Alitta virens (Sars, 1835) | Norway. | Hartman (1956) placed the species in Nereis riisei, and Pettibone (1963) transferred it to Alitta virens. No further comments about synonymies were made, so a revision is needed. |
| Leptonereis mexicana Treadwell, 1942 | Topolobampo Bay, Mexico | Rullierinereis mexicana (Treadwell, 1942) | -- | Pettibone (1971) redescribed this species and transferred it to Rullierinereis, but regarded it as an amphiamerican species. Further examination of type and additional materials is needed to ensure its wide distribution. |
| Ceratonereis longicaudaTreadwell, 1943 | Padada, Davao del Sur, Philippines | Neanthes pachychaeta (Fauvel, 1918) | Sarodrano, Madagascar. | Glasby et al. (2011) subjectively retain the synonymy of this species with N. pachychaeta. Examination of type material is needed to reassess its status. |
| Eunereis africanaTreadwell, 1943 | Lobito, Angola | Platynereis dumerilii (Audouin & Milne-Edwards, 1833) | La Rochelle, France. | Hartman (1951) synonymized it with P. dumerilii without further explanation, requiring examination of type material to ensure they are identical. |
| Nereis singularisTreadwell, 1943 | Newfoudland Basin, Northern Atlantic Ocean | Platynereis singularis (Treadwell, 1943) | -- | Hartman (1956) suggested this species could be the same as Ceratonereis singularis. Conde-Vela (2021b) transferred it to Platynereis after the examination of type material. |
| Perinereis diversidentataTreadwell, 1943 | Cape Cross, Namibia | Perinereis diversidentata (Treadwell, 1943) | -- | Day (1953) synonymized it with P. variegata. Here it is redescribed and regarded as a Perinereis valid species. |
A trend of Treadwell making better and more complete descriptions of nereidids over time was observed. A common practice in the works of Treadwell consulted is the lack of comparisons between his new species and the pre-existent ones. This is the case of Nereis (Neanthes) palpata and Nereis disparsetosa. Furthermore, these species by themselves are evidence that Treadwell did not have a consistent scheme on the use of genera or subgenera in nereidids: Nereis palpata was placed in the subgenus Neanthes, whereas Nereis disparsetosa was not, even though it is very similar. Other examples are when he recognized Leptonereis as a subgenus of Nereis in Nereis (Leptonereis) distorta Treadwell, 1936 but as valid genus for Leptonereis egregicirrata Treadwell, 1924 or Leptonereis mexicana Treadwell, 1942. Regardless of this inconsistency throughout his work, Treadwell made a remarkable effort in the description of several new species, and his proposed species are therefore encouraged to be reevaluated.
