Introduction

Passalidae are a pantropical group of Coleoptera. In the Western Hemisphere, the family is represented by the tribes Proculini and Passalini. Passalus is the most speciose genus of Passalini. Within Passalidae, Passalus is the genus with the widest geographic distribution, being found from the United States to Argentina (^{Jiménez-Ferbans, Reyes-Castillo, Schuster, & Salazar, 2013}; ^{Schuster, 1983}). Veturius is the most speciose genus of Proculini. These 2 genera are rich in South and Central America, but Passalus (Passalus) is richer in the Amazon lowlands and many Proculini genera are richer in the mountains of South and Central America.

In their Passalidae catalog, ^{Hincks and Dibb, 1935}, ^{Hincks and Dibb, 1958} cite 48 species of Passalidae for Costa Rica, the majority being Passalus. However, no recent monograph accurately lists the number of bess beetle species in this country. As a contribution to the documentation of the biodiversity of Costa Rica, we present a checklist of Passalidae from Costa Rica (Table 1) and describe 2 new species of Passalus from the montane areas of the Sierra de Talamanca.

Materials and methods

For the list of species, we follow the classification of ^{Boucher (2006)}; for the descriptions, we use the terminology of ^{Boucher (2006)} for the cephalic region (except when indicated) and ^{Reyes-Castillo (1970)} for the rest of the body. We used a caliper for metric measurements; illustrations were made using a camera lucida. The specimens are deposited in the following entomological collections: Colección Entomológica del Instituto de Ecología, A. C., México (IEXA); Colección Nacional de Insectos del Instituto de Biología, Universidad Nacional Autónoma de México (CNI-UNAM); Colección Entomológica, Universidad del Magdalena, Colombia (CBUMAG-ENT); Colección de Artrópodos de la Universidad del Valle de Guatemala (UVGC); Michigan State University Collection (MSUC); The Field Museum of Chicago (FMNH); and the personal collection of Dr. Alan Gillogly in Caldwell, USA (ARGC).

To elaborate the checklist (Table 1), we surveyed literature to gather information about the Passalidae from Costa Rica and reviewed material deposited in the collections cited above, and also we reviewed material from the American Museum of Natural History, New York (AMNH); United States National Museum of Natural History, Washington (USNM); California Academy of Sciences, San Francisco (CAS); Carnegie Museum of Natural History, Pittsburg (CMNH); Philadelphia Academy of Natural Sciences, Philadelphia (PANS); Museo de Historia Natural de Costa Rica, San José (MHNCR); Museo de Entomología de la Facultad de Agronomía de la Universidad Nacional Autónoma de Costa Rica, San José (MEUNCR); Centro Agronómico Tropical de Investigación y Enseñanza, San José (CATIEC), Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo (MZSP); Institut Royal des Sciences Naturelles, Brussels (IRSN); Muséum National d’Histoire Naturelle, Paris (MNHN); and Museo di Zoologia della Universitá di Torino, Torino (MZUT).

Descriptions

Passalus (Pertinax) halffterorum n. sp. (Fig. 1)

Figure 1 Passalus (Pertinax) halffterorum n. sp.; A, head and anterior part of pronotum; B, ventral view of aedeagus; C, lateral (left) view of aedeagus; D, dorsal view of aedeagus. Scale bars: 1 mm. 

Description: Habitus: midsize, total length 24.0–28.9 mm, brachypterous, body convex shiny black. Head: labrum with anterior border straight or slightly concave, covered with scarce setae, setae are less dense in medial labrum. Clypeus hidden under the frons, with anterior angles strongly developed under the mediofrontal tubercles and of similar size as mediofrontal tubercles. Frons wide, anterior frontal edge with small middle indentation, without secondary mediofrontal tubercles. Mediofrontal tubercles projected forward, smaller than inner tubercles. Inner tubercles conical, with free apex, joined to mediofrontal tubercles by a weak ridge, placed mid distance between the mediofrontal tubercles and the central tubercle apex. Posterofrontal ridges “V” shaped. Area between the frontal ridges heavily punctuated on the anterior half. Cephalic mamelon (sensu^{Jiménez-Ferbans & Reyes-Castillo, 2014}) present and whole. Mesofrontal structure of the “marginatus” type (^{Reyes-Castillo, 1970}), with central tubercle wide at the base, with or without a sulcus in the posterior part, apex not free. Lateroposterior tubercles marked. Lateropostfrontal areas glabrous, shiny, and impunctate. Eyes reduced, with canthus covering ½ of the eye in lateral view. Canthus glabrous or with 3 setae at the margin of the eye. Postfrontal groove semicircular and complete. Hypostomal process slightly separated from mentum, glabrous and reaching the superior part of the middle zone of the mentum. Medial basal mentum protruding ventrally, with fine line of setae at the posterior margin and reduced punctures (4) on its anterior border. Mentum with large lateral fossae, deep, glabrous and opaque. Antennal club trilamellate, with lamellae short (h longer than w, Fig. 1A). Internal tooth of the left mandible bidentate, simple on the right mandible. Dorsal tooth straight in dorsal view and slightly concave in lateral view. Dorsal mandibular pubescence covering the base of the mobile tooth and reaching the base of the internal tooth. Mandibular fossae short, reaching only half of the base of the mobile tooth. Maxilla with lacinia bidentate at the apex. Ligula tridentate, with middle tooth longer than lateral teeth. Middle palpomere of the labial palp 1.2 times wider and with the same length as the distal palpomere.

Thorax: pronotum with anterior angles sharp and posterior angles rounded, wider than elytra, with punctuations restricted to the lateral fossae areas. Marginal groove wide, occupying – of the anterior margin of the pronotum, impunctate on the posterior half. Longitudinal sulcus well marked. Lateral fossae slightly marked, with 2 punctures on the right side and smooth on the left side. Punctures of the pronotum restricted to the marginal groove and fossae. Prosternellum rhomboidal, shiny. Pre-epimeron (sensu^{Reyes-Castillo, 1970}) shiny and glabrous. Mesosternum without mesosternal scar, indicated only by an opaque anterior area, impunctate and glabrous; lateral area opaque. Posterior corner of the mesepisternum and mesepimere glabrous. Anterolateral part of metasternum smooth and glabrous, but with moderate punctures with 1–2 minute setae on the sides of mesocoxae. Metasternal disc short, strongly convex posteriorly, with dense strong punctures, rarely with 1 or 2 punctures; delimited by numerous strong punctures medially and posteriorly. Posterior metasternal lateral fossa of the same width as epipleura and narrower than mesotibia.

Elytra: shiny, anterior border rounded and glabrous. Humeri with scarce minute setae. Epipleura with reduced group of short setae basally. Striae with rounded punctures, marked on both lateral and dorsal striae.

Legs: femur I with ventral anterior marginal sulcus wide and incomplete, not reaching the apical pubescence. Tibia I with dorsal sulcus complete or incomplete. Tibia II with 2 strong spines and 1 weak spine. Tibia III with moderately strong spine.

Abdomen: last sternite with marginal groove incomplete.

Aedeagus: basal piece partially fused with parameres in ventral view (Fig. 1B). Median lobe almost entirely sclerotized on ventral surface, length is 1.1 times the length of the basal piece and parameres, measured at the median ventral line. Lateral projections of the parameres large and apex truncated in lateral view (Fig. 1C).

Variation: the medial part of the mentum completely glabrous or with a line of setae on its posterior margin, rarely completely pubescent. Some specimens without left pronotal fossa, others with up to 3 punctures in each fossa. Some with small mesosternal scars. Mesotibia in MSU specimen with 3 weak spines on left, 1 strong and 1 weak on right.

Taxonomic summary

Holotype male. Costa Rica: Villa Mills, Cerro de la Muerte, “53”, 18.II.1975/Passalus (Pertinax) sp. nov. Reyes-Castillo det. 1987 (IEXA).

Paratypes (2♀♀, 1♂ and 44 sex unknown). Costa Rica: Villa Mills, Cerro de la Muerte [with numbers 48, 49, 50, 53, 54 in each specimen], 18.II.1975/Passalus (Pertinax) sp. nov. Reyes-Castillo det. 1987 (5 specimens, sex unknown, IEXA). 2♀♀, Costa Rica: San José, C. de la Muerte, Auxiliadora, 2,700 m snm, 1.IX.2000, I. Chacon y J. Monzón. (UVGC). Costa Rica: Prov. San José. San Isidro del General Cerro de la Muerte. 23.IX.1969. P. Reyes y G. Halffter, cols./Bosque de Encinos. alt. 2,750 m. En tronco de encino (8 specimens, sex unknown, 7 IEXA, 1 FMNH). Costa Rica: Prov. San José. Villa Mills. 23.IX.1969 P. Reyes y G. Halffter, cols./Bosque de Encinos. alt. 2,750 m. En tronco podrido (13 specimens, sex unknown, 10 IEXA, 3 CBUMAG-ENT); same data as previous 19.IX.1969/Bosque de encino. alt. 2,680 m. En tronco podrido (3 specimens, sex unknown, IEXA); same data as previous 20.IX.1969 (4 specimens, sex unknown, IEXA). Costa Rica: San José. Villa Mills. Elv. 3,075 m. 14.VIII.1967 [R. Pope, leg.] (10 specimens, sex unknown, 5 IEXA, 5 CBUMAG-ENT). Costa Rica, Cerro de la Muerte 25.VIII.1970 Pat Rich (1 specimen, sex unknown, MSUC). Costa Rica, 31 mi.[km?] SSE Cartago, Tres de Junio Mountain, 7.II.1971, under log, R. Foster (1♂, 4 specimens, sex unknown, ARGC).

Etymology: this species is named in honor of Gonzalo Halffter and Violeta Halffter, distinguished coleopterists, founders of the Instituto de Ecología, A.C., Xalapa, with whom the second author (PRC) had the privilege of collecting passalids in Costa Rica with the support of the OTS.

Remarks

Passalus halffterorum n. sp. has the middle tibias armed and reduced eyes, similar to Passalus spinosus and Passalus spiniger; however, in these latter species the posterior tibias are strongly armed and the frontal ridges have secondary internal teeth, different from P. halffterorum n. sp. Likewise, a distinct characteristic of P. halffterorum n. sp. is the evident hind wing reduction (brachypterous), with the pronotum wider than the base of the elytra.

Passalus (Pertinax) rzedowskiorum n. sp. (Fig. 2)

Figure 2 Passalus (Pertinax) rzedowskiorum n. sp.; A, head and anterior part of pronotum; B, ventral view of aedeagus; C, lateral (left) view of aedeagus; D, dorsal view of aedeagus. Scale bars: 1 mm. 

Description: habitus: midsize, total length 26.0–35.8 mm, hemibrachypterous, body convex shiny black. Head: labrum with anterior border slightly concave, covered with scarce setae that are less dense anteromedially. Clypeus hidden under the frons, with anterior angles reduced, placed under the mediofrontal tubercles, smaller than mediofrontal tubercles. Frons wide, anterior frontal edge with light or strong medial indentation (notched), without secondary mediofrontal tubercles. Mediofrontal tubercles projected forward, larger than inner tubercles. Inner tubercles conical, projected upwards, joined to mediofrontal tubercles by a weak ridge, placed at mid distance between the mediofrontal tubercles and the central tubercle apex. Posterofrontal ridges “V” shaped. Area between frontal ridges heavily punctate on the anterior half. Cephalic mamelon (sensu^{Jiménez-Ferbans & Reyes-Castillo, 2014}) present and whole. Mesofrontal structure of the “marginatus” type (^{Reyes-Castillo, 1970}), with central tubercle wide at the base, without a sulcus posteriorly, apex not free. Lateroposterior tubercles marked. Lateropostfrontal areas glabrous, shiny, and mostly impunctate, but with conspicuous striae. Eyes reduced, with canthus covering 2/3 of the eye in lateral view. Canthus glabrous. Postfrontal groove complete with an inverted “V” at the mid-part. Hypostomal process slightly separated from mentum, glabrous and reaching the upper part of the mid zone of the mentum. Medial-basal mentum protruding ventrally, pubescent on the posterior half. Mentum with big lateral fossae, deep and glabrous. Antennal club trilamellate, with short lamellae. Mandibles tridentate on the apex, with teeth of similar size. Internal tooth of the left mandible bidentate, simple on the right mandible. Dorsal tooth straight in dorsal view and slightly concave in lateral view. Dorsal mandibular pubescence covering the base of the mobile tooth and reaching the base of the internal tooth. Mandibular fossae covering entirely the base of the mobile tooth. Maxilla with lacinia bidentate at the apex. Ligula tridentate, with middle tooth longer and lateral teeth reduced. Middle palpomere of the labial palp 1.5 times wider and with almost the same length as the distal palpomere.

Thorax: pronotum square, with anterior angles sharp and posterior angles rounded, slightly wider than elytra, with punctuations restricted to the lateral fossae area (1 or 2 punctures) and marginal groove. Marginal groove wide, occupying ½ of the anterior margin of the pronotum. Longitudinal sulcus well marked. Lateral fossae slightly marked, with or without punctures. Prosternellum rhomboidal. Pre-epimeron (sensu^{Reyes-Castillo, 1970}) shiny and glabrous. Mesosternum with mesosternal scar slightly marked, oval shaped, impunctate and glabrous; lateral area opaque. Posterior corner of the mesepisternum and mesepimere glabrous. Anterolateral part of metasternum smooth and glabrous. Metasternal disc short, slightly convex posteriorly, without or with scarce punctures (4); delimited by numerous punctures medially and posteriorly. Posterior metasternal lateral fossa narrower than epipleura.

Elytra: shiny, anterior border rectangular and glabrous. Humeri and epipleura glabrous. Striae with rectangular punctures, marked on both lateral and dorsal striae.

Legs: femur I with ventral anterior marginal sulcus wide and complete, reaching the apical pubescence. Tibia I with dorsal sulcus complete or incomplete. Tibia II with 1 strong spine and 1 weak spine. Tibia III with moderately strong spine.

Abdomen: last sternite with marginal groove incomplete.

Aedeagus: basal piece fused with parameres in ventral view (Fig. 2B). Median lobe almost entirely sclerotized on ventral surface, length is 1.1 times the length of the basal piece and parameres, measured at the medial ventral line. Lateral projections of the parameres large and apex rounded in lateral view (Fig. 2C).

Variation: the notch in frons can be well marked (deep) or weak. The mestasternal disc can be smooth or with scarce punctures (4 punctures).

Taxonomic summary

Holotype male. Costa Rica: Prov. San José. San Isidro del General 21.IX.1969. P. Reyes y G. Halffter, cols./Selva tropical de montaña, alt. 1480 m. en tronco podrido (IEXA).

Paratypes (3♀♀ and 8 sex unknown). 1♀ and 2 sex unknown, Costa Rica: Prov. San José, San Isidro del General. 21-IX-1969. P. Reyes y G. Halffter, cols./Selva tropical de montaña, alt. 1,480 m. en tronco podrido (IEXA). 2♀♀ and 2 sex unknown, Costa Rica: Prov. San José, San Isidro del General, 22.IX.1969. P. Reyes y G. Halffter, cols./Selva tropical de montaña, alt. 1,480 m. en tronco podrido, (3 IEXA, 1 CBUMAG-ENT). 2 sex unknown, Costa Rica: Prov. San José, Rd. to San Isidro el General, ~2700 m, 6.II.1979. N. Rizzo (UVGC). 1 sex unknown, Costa Rica: Prov. San José, PanAmerican Hwy, km 70. Mirador del Quetzal. 9°38’37” N, 83 51’2” W. 2,690 m. 20.VII.2000. J. Asche, R. Brooks, Z. Falin CR1 ABFOO 198 ex. under logs//SMO 204354 KUNHM-ENT (UVGC). 1 sex unknown, Costa Rica: P.N. Tapanti, La Esperanza 2680 m Monzón y Camposeco/Passalus (Pertinax) sp. nov. det.: Jiménez-Ferbans (UVG).

Etymology: this species is named in honor of Jerzy Rzedowski and Graciela Calderón de Rzedowski, emeritus researchers of the Instituto de Ecología A.C., for their contributions and studies on taxonomy and biogeography of the Mexican flora.

Taxonomic remarks: the meso- and metatibiae with moderate strong spine relates P. rzedowskiorum with the Rhodocanthopus species group (sensu ^{Jiménez-Ferbans, Reyes-Castillo, & González, 2016}), especially with species with strong elytral striae. However, the shape of anterior part of elytra (humeri very acute) and the body size easily distinguish P. rzedowskiorum. Another characteristic trait of P. rzedowskiorum is its lateropostfrontal areas (frontal fossae sensu ^{Reyes-Castillo, 1970}) with conspicuous striae.

Nomenclatural comments of the checklist

Passalus (Pertinax) clypeoneleus (Kuwert, 1891): ^{Hincks and Dibb (1935)} considered Rhodocanthopus spineus ^{Kuwert, 1898} as a synonym of P. clypeoneleus. However, here we synonymized R. spineus Kuwert with Passalus spinosus (Kuwert). As established in this work, Rhodocanthopus formosiceps Kuwert, 1891, which is considered a synonym of Passalus caelatus Erichson, is actually a synonym of Passalus clypeoneleus (Kuwert). These proposals are based on examination of the type material of these 4 species, deposited in the Museum National d’Histoire Naturelle in Paris.

Verres corticicola (Truqui, 1857): ^{Hincks and Dibb (1935)} considered Verres angustatus Kuwert, 1891 as a valid species. Examination of the type material of V. angustatus, deposited in the Museum National d’Histoire Naturelle in Paris, allows us to propose this species as a synonym of Verres corticicola (Truqui).

Verres deficiens Kuwert, 1991: in the catalogue of ^{Hincks and Dibb (1935)}, V. deficiens Kuwert is considered as a synonym of V. furcilabris (Eschscholtz). We have examined the type material of V. deficiens and consider it as a valid species. Likewise, we have examined the type material of Verres deflexicornis ^{Kuwert, 1998} and this species must be considered as synonym of Verres deficiens Kuwert. The types of Kuwert's species are deposited in the Museum National d’Histoire Naturelle in Paris.

Verres hageni^{Kaup, 1871}: V. vernicatus Casey, 1897 was revalidated by ^{Hincks (1950)} in his key to the species of Verres. After examining the type material, deposited in the United States National Museum, Smithsonian Institution in Washington, D.C., we propose V. vernicatus Casey, as a synonym of Verres hageni Kaup.

Species with erroneous or dubious literature records

Passalus (Pertinax) perparvulus (Kuwert): cited from Costa Rica by ^{Pangella (1905)}. We have examined the specimen studied by ^{Pangella (1905)} (deposited in MZUT) and it is very similar to small specimens of P. caelatus Erichson, with which it could be a synonym.

Passalus (Pertinax) spinipes Gravely: originally described from Nicaragua, ^{Hincks (1934)} cited it from Costa Rica; we have not studied specimens from Costa Rica.

Passalus (Passalus) interruptus (Linnaeus): a species from South America, its distributional northern boundary is the Panama Canal (^{Reyes-Castillo & Castillo, 1992}). The Costa Rican specimens cited as P. interruptus may correspond to P. (Passalus) punctiger Lepeletier & Serville. Following the criterion of ^{Reyes-Castillo and Castillo (1992)}, we have excluded this species from the list.

Passalus (Passalus) labroexcisus (^{Kuwert): described by Kuwert (1898)} based on 1 specimen without locality, was considered a synonym of P. punctiger Lepeletier & Serville in the catalogue of ^{Hincks and Dibb (1935)}. However, P. labroexcisus was treated as a valid species by ^{Luederwaldt (1934a)}, who studied a specimen of the A. Alfaro collection from “Costa Rica, Tempique, I-1932”. Finally, ^{Hincks and Dibb (1958)} followed the criterion of ^{Luederwaldt (1934a)} and assigned it to the “Phoroneus” section of Passalus.

Passalus (Passalus) nevermanni^{Luederwaldt, 1941}: described from Costa Rica in a posthumous publication, this species would correspond to a synonym of P. (Passalus) punctiger Lepeletier & Serville. In the description, ^{Luederwaldt (1941)} only cited a specimen from “Costa Rica, I-1933” in the collection of F. Nevermann.

Yumtaax recticornis (Burmeister): cited from “La Palma”, Costa Rica by ^{Alfaro (1935)}, is a montane species endemic to Mexico (^{Castillo & Reyes-Castillo, 1984}). We have excluded this species from the list.

Heliscus wagneri (Kaup): although the original description by ^{Kaup (1868)} cites a specimen from Guatemala, a later work (^{Kaup, 1871}: 108–109) only mentions 2 specimens from Nicaragua; it is cited from Costa Rica by ^{Biolley (1901)}; ^{Reyes-Castillo (1970)} confused it with Petrejoides subrecticornis (Kuwert). We have not seen specimens or the type.

Proculus mniszechi Kaup: this species was cited from the humid mountains of Carrillo (Braulio Carrillo, National Park) in Costa Rica by ^{Alfaro (1935)}. However, it is endemic to Guatemala and Honduras (^{Schuster, Cano, & Reyes-Castillo, 2003}) and we know of no specimens from Costa Rica. We have excluded this species from the list.

Veturius (Publius) crassus (Smith): is described from Colombia; ^{Luederwaldt (1934b)} cited it from Costa Rica as did ^{Alfaro (1935)} from Volcán Irazú (3,400 m). However, ^{Reyes-Castillo and Castillo (1992)} rejected that citation, indicating that V. crassus is endemic to Colombia; the same was said by ^{Boucher (2006)}. We have excluded this species from the list.

Discussion

We have listed 53 species of Passalidae of Costa Rica (18 Passalini and 35 Proculini). This is a relative high level of richness, considering that Costa Rica has an area of 51,100 km², compared with the number of species in larger countries like Guatemala (90 species), Mexico (83 described species and 22 not described, ^{Reyes-Castillo, Rojas-Gómez, & Vázquez, 2006}) and Colombia (87, ^{Amat-García, Blanco-Vargas, & Reyes-Castillo, 2004}).

Proculini dominate the composition of Passalidae in Costa Rica, similar to what occurs in Guatemala and Mexico, but different from what occurs in South America. However, a high percentage of Costa Rican Proculini (35 species) belong to Veturius (12 species), which is a highly diversified genus in South America. The other speciose genera in Costa Rica are Petrejoides and Verres (6 species each), which have an important level of diversification in the southern part of Central America. On the other hand, Passalini are dominated by Passalus (Pertinax) having 11 of the 18 species of the tribe; of these 11 species, 6 belong to the Rhodocanthopus species group (sensu^{Jiménez-Ferbans, Reyes-Castillo, & González, 2016}), which has a clear Mesoamerican lowland distribution (^{Jiménez-Ferbans et al., 2016}).

There are 13 endemic species of Passalidae in Costa Rica, most of them distributed in mountainous areas. The genus with more endemic species is Petrejoides, in which 3 of the 6 species are exclusive for Costa Rica. Likewise, the genus Veturius shows a high level of endemism in the region of the Sierra de Talamanca (between Costa Rica and Panama). This pattern of endemism in the high mountain area is common in Passalidae from Mexico to northern South America (^{Gutiérrez-Velázquez, Rojas-Soto, Reyes-Castillo, & Halffter, 2013}; ^{Schuster, 1978}), and normally is dominated by species of Proculini and species of Passalus (Pertinax).

Concluding, the Costa Rican passalid fauna is relatively well known compared to nearby countries. However, more exploration is required in habitats with the highest levels of endemism (i.e. montane cloud forests), in order to complete the list of the Passalidae of this country.