1. Introduction and geological setting

San Feliciano hill is located on the southwestern side of Monti Berici between Orgiano and Lonigo (Figure 1). The studied specimens are preserved within the limestones including coralline algae and corals from the late Eocene (Priabonian), located in San Feliciano hill (Orgiano, Monti Berici, Vicenza, NE Italy) (Figure 2). The stratigraphic unit is the so-called “Formazione di Priabona” (late Eocene, Priabonian). The micro-fossil analysis by nannofossils provided by ^{Beccaro (2003)} confirmed the Priabonian age for all layers present in the quarry. The lowest layers are represented by a well-stratified greyish marly-limestone formation including many algae, nummulites, bivalves, several echinoderms, and rare decapod crustaceans [Palaeocarpilius macrocheilus (^{Desmarest, 1822})]. White-yellowish calcarenites, 6-7 meters thick, overlap the lower layers. These calcarenites including coralline algae, corals, rare mollusk casts, and decapod crustaceans (^{De Angeli, 2016}; ^{Quaggiotto and De Angeli, 2019}). Finally, the upper part is represented by marly limestones including nummulites, bryozoans, bivalves, and echinoderms. Many decapod crustaceans collected within the calcarenites were described by several authors (^{Fabiani, 1911}; ^{De Angeli and Garassino, 2002}, ²⁰¹⁴, in press; ^{De Angeli and Lovato, 2009}; ^{De Angeli et al., 2010a}; ^{De Angeli, 2016}). The studied specimens, subject of this note, were collected from this calcarenite level of the quarry.

Figure 1 Map of Monti Berici with location (*) of San Feliciano hill (Orgiano, Monti Berici, Vicenza, NE Italy). 

Figure 2 Close-up of the limestones including coralligenous algae and corals from the late Eocene (Priabonian) of San Feliciano hill. 

2. Material

The material includes 10 specimens, housed in the Museo Civico “Domenico Dal Lago” of Valdagno (Vicenza, NE Italy) (MCV). The sizes are expressed in millimetres. Anatomical abbreviations - lcxp: carapace length; wcxp: carapace width; wof: orbitofrontal margin width; wf: frontal width.

3. Systematic paleontology

Order Decapoda ^{Latreille, 1802}

Infraorder Brachyura ^{Latreille, 1802}

Section Eubrachyura de ^{Saint Laurent, 1980}

Subsection Heterotremata ^{Guinot, 1977}

Superfamily Majoidea ^{Samouelle, 1819}

Family Epialtidae ^{MacLeay, 1838}

Subfamily Epialtinae ^{MacLeay, 1838}

Genus Bericirinia n. gen.

Diagnosis: Triangular carapace, larger posteriorly, considerably wider than long, convex longitudinally; wide front; short, bifid rostrum, separated by U-shaped notch; preorbital angle blunt; orbits laterally directed; intercalated spine not present; divergent, smooth anterolateral margins; short posterolateral margins, strongly convergent; dorsal regions slightly raised and marked by weak grooves; frontal region with an axial depression running between epigastric lobes and protogastric regions; gastric, cardiac, and branchial regions with some tubercles and ovate swellings; dorsal surface with a scabrous-shaped small granules.

Etymology: from Monti Berici where the studied specimen was collected. Gender: feminine.

Type species: Bericirinia bretoni n. gen., n. sp., by monotypy.

Discussion: Based upon ^{Davie et al., (2015)} and ^{Schweitzer et al., (2020)}, Bericirinia n. gen. shows the main morphological characters shared with many spider crabs, such as the triangular carapace, larger posteriorly; narrow frontal margin; and orbits laterally directed. Moreover, the short, bifid rostrum and the lacking of the intercalated spine allow to assign the new genus to the Epialtidae ^{MacLeay, 1838}. ^{Schweitzer et al., (2020)} provided a new classification of the Majoidea and within the Epialtidae which includes five fossil genera (Epialtus^{H. Milne Edwards,1834}; Bolcapisa Beschin, Busulini and Tessier in ^{Beschin et al., 2016}; Eoinachoides^{Van Straelen, 1933}; Nanomaja^{Müller and Collins, 1991}; Panticarcinus^{Collins and Saward, 2006}) and one extant-fossil genus (Pugettia^{Dana, 1851}), Panticarcinus from the early Eocene (Ypresian) of UK is the only genus which shows affinities with Bericirinia n. gen. Indeed, both genera share the triangular carapace, larger pos-teriorly; oblique, divergent anterolateral margins; and dorsal regions with swellings and tubercles. Panticarcinus, however, differs from the new genus in having the carapace longer than wider and elongate single rostrum.

Bericirinia bretoni n. gen., n. sp.

Figure 3

Figure 3 Bericirinia bretoni n. gen., n. sp., holotype, MCV.21/003-I.G.21.23; 1. dorsal view; 2. dorsal digital reconstruction; 3. lateral view; 4. frontal view. Scale bar equals 5 mm. 

Diagnosis: as for the genus.

Etymology: the species is named in honour of Gérard Breton (1944-2020), in recognition of his major contributions to the knowledge of the palaentology and invertebrate fossils.

Holotype: MCV.2021/003-I.G.21.23, by monotypy.

Type locality: San Feliciano hill (Orgiano, Monti Berici, Vicenza, NE Italy).

Geological age: late Eocene (Priabonian).

Material and measurements: one carapace in dorsal view (MCV.2021/003-I.G.21.23 - lcxp: 32.8 mm, wcxp: 34.2 mm, wof: 18 mm).

Description: Triangular carapace, convex longitudinally, larger posteriorly, slightly wider than long (lcxp/wcxp = 0.95), widest between angles of antero- and posterolateral margins; wide front; short, bifid rostrum, separated by

U-shaped notch; preorbital angle blunt; orbits laterally directed; divergent, elongate, and smooth anterolateral margins; short posterolateral margins, strongly convergent; relatively wide posterior margin, partially preserved; dorsal regions slightly raised and marked by shallow grooves; frontal region depressed axially; frontal axial depression running along epigastric and protogastric regions; epigastric lobes with two ovate swellings; raised protogastric regions with three swellings; relatively raised metagastric regions with two swellings; narrow, depressed urogastric region; cardiac region well marked by branchiocardiac grooves laterally, with two swellings; branchial region marked anteriorly by cervical groove with one strong epibranchial swelling, one weakly raised transverse mesobrachial swelling, and one weakly transverse metabranchial swelling; dorsal surface with a scabrous-shaped small granules.

Superfamily Dairoidea ^{Serène, 1965}

Family Dairidae ^{Ng and Rodriguez, 1986}

Genus Orgianocarcinus nov.

Diagnosis: Obovate, convex carapace, wider than long; narrow front, slightly downturned and axially depressed; round orbits having supraorbital margin with two narrow fissures; convex anterolateral margin with 7 spines; short, concave posterolateral margin with 6-7 spines; straight posterior margin; well-distinct dorsal regions with large, obovate or rounded crater-shaped lobules, surrounded by smaller tubercles.

Type species: Orgianocarcinus bericus n. gen., n. sp., by monotypy.

Etymology: from San Feliciano hill Orgiano, where the studied specimens have been collected and carcinus = crab. Gender: masculine.

Discussion: The main morphological characters of the studied specimens fit those of the Dairidae ^{Ng and Rodriguez, 1986}. Indeed, the rounded shape of the orbits, with raised, tuberculate supra-orbital margin; bilobate front, slightly downturned; and antero- and posterlateral margins with spines are shared with the extant and fossil Daira^{De Haan, 1833}, well known from the Paleogene of Veneto with several species (^{De Angeli and Garassino, 2006}; ^{De Angeli et al., 2019}). Orgianocarcinus n. gen. differs, however, in having dorsal regions with some large obovate or rounded crater-shaped tubercles (vs. dorsal regions with many small mushroom-shaped lobules uniformly arranged in Daira). Although the studied specimen lacks the ventral parts, useful for its systematic assignment, the closer affinities are with the representatives of the Dairidae to which it is confidentially assigned.

The ornamentation with large obovate or rounded crater-shaped lobules, resembling the coral look, could be a perfect camouflage system for Orgianocarcinus n. gen. which lived within the corals.

Orgianocarcinus bericus n. gen., n. sp.

Figure 4

Figure 4 Orgianocarcinus bericus n. gen., n. sp., 1. holotype, MCV.21/008-I.G.21.28, dorsal view; 2. paratype, MCV.21/004-I.G.21.24, dorsal view; 3. paratype, MCV.21/010-I.G.21.30, dorsal view; 4. paratype, MCV.21/006-I.G.21.26, dorsal view; 5. paratype, MCV.21/009-I.G.21.29, dorsal view; 6. paratype, MCV.21/007-I.G.21.27, dorsal view. Scale bar equals 5 mm. 

Diagnosis: as for the genus.

Etymology: The trivial name alludes to Monti Berici where the studied specimens have been discovered.

Holotype: MCV.21/008-I.G.21.28.

Paratypes: MCV.21/004-I.G.21.24; MCV.21/ 005-I.G.21.25;MCV.21/006-I.G.21.26; MCV.21/ 007-I.G.21.27; MCV.21/009-I.G.21.29; MCV.21/ 010-I.G.21.30.

Geological age: late Eocene (Priabonian).

Type locality: San Feliciano hill (Orgiano, Monti Berici, Vicenza, NE Italy).

Material and measurements: seven specimens with well-preserved carapace (MCV.21/004-I.G.21.24 - lcxp: 8.2; wcxp: 11.4; wof: 6; wf: 4.2; MCV.21/005-I.G.21.25 - lcxp: 8.4; wcxp: 11.8; MCV.21/006-I.G.21.26 - lcxp: 7.7; wcxp: 10.8; wof: 5.8; MCV.21/007-I.G.21.27 - lcxp: 4.9; wcxp: 6.9; MCV.21/008-I.G.21.28 - wcxp: 9.4; MCV.21/009-I.G.21.29 - wcxp: 8; MCV.21/010-I.G.21.30 - lcxp: 5; wcxp: 7).

Description: Obovate carapace, convex in both sections, above all longitudinally, wider than long (lcxp/wcxp = 0.71); wide orbitofrontal margin half of maximum carapace width; front weakly protruded beyond orbits, slightly down-turned and axially depressed; round orbits; raised supraorbital margin with two narrow fissures; preorbital angle with one tubercle; medial orbital tooth with one tubercle; subtriangular extraorbital tooth; convex anterolateral margin with 7 spines; short, slightly concave posterolateral margin with 6-7 spines; straight posterior margin, as wide as front; dorsal regions well marked by grooves; frontal region with medial longitudinal depression; epigastric lobes with two ovate swellings; slightly raised protogastric regions with tubercles; sub-triangular, elongate mesogastric region with one longitudinal, ovate lobe; well-distinct metagastric region with one large ovate lobe; subpentagonal cardiac region with two lobes anteriorly and one lobe posteriorly; depressed intestinal region with a transverse row of 6-7 tubercles; triangular hepatic regions well marked by cervical groove with three lobes; branchial regions with 4 epibranchial lobes, 4 mesobranchial lobes, and three smaller meta-branchial lobes.

Cephalic and thoracic appendages and ventral parts not preserved.

Superfamily Xanthoidea ^{MacLeay, 1838} (incertae sedis)

Genus Actaeites^{Müller and Collins, 1991}

Type species: Actaeites lobatus^{Müller and Collins, 1991}, by monotypy.

Fossil species: Actaeites lobatus^{Müller and Collins, 1991}.

Actaeites lobatus^{Müller and Collins, 1991}

Figure 5

Figure 5 Actaeites lobatus^{Müller and Collins, 1991}, 1. MCV.21/001-I.G.21.21, dorsal view; 2. MCV.21/002-I.G.21.22, dorsal view. Scale bar equals 5 mm. 

Actaeites lobatus^{Müller and Collins, 1991: 70, fig. 4c, Pl. 4, figs. 9, 10}.

Actaeites lobatus - ^{Karasawa and Schweitzer, 2006: 50}. - ^{Beschin et al., 2007: 56, Pl. 9, figs. 2a-b, 3, 4}. - ^{De Angeli and Beschin, 2008: 32, fig. 10, Pl. 4, fig. 4.} - ^{De Angeli et al., 2010b: 167, fig. 13}. - ^{Schweitzer et al., 2010: 129}. - ^{Beschin et al., 2015: 93, Pl. 7, fig. 4}. - ^{Beschin et al., 2016: 137, Pl. 17, fig. 8}. - ^{Beschin et al., 2018: 196, fig. 128a, b}. - ^{De Angeli et al., 2019: 37}.

Geological age: late Eocene (Priabonian).

Locality: San Feliciano hill (Orgiano, Monti Berici, NE Italy).

Material and measurements: two specimens with well-preserved carapace (MCV.21/001-I.G.21.21 - lcxp: 10; wcxp: 12; MCV.21/002-I.G.21.22 - lcxp: 15.1, wcxp: 29; wo-f: 14.8; wof: 8).

Emended diagnosis: Convex carapace, wider than long; bilobate front, depressed axially, with small marginal spines; orbits moderately wide, separated from the front by a deep groove; supraorbital margins with two fissures; convex anterolateral margins with three spines (excluding the extraorbital spine); dorsal regions of the carapace covered by small tubercles uniformly arranged, marked by smooth grooves.

Discussion: Actaeites lobatus was described based upon the morphological characters of the holotype (MAFI EF-22.1 [M.91-153]) from the Priabonian of Budapest (^{Müller and Collins, 1991}). The orbitofrontal margin poorly preserved and the lacking of ventral parts did not allow a right systematic assignment of this species (^{Karasawa and Schweitzer, 2006}). Fortunately the studied specimens preserved the anterior part of the carapace, lacking in the holotype, allowing to amend the original diagnosis. Moreover, one studied specimen (MCV.21/001-I.G.21.21) preserves incomplete chelipeds, walking legs, and three male pleonal somites. The chelipeds have carpus and propodus covered by small tubercles. The dorsal regions of the carapace are covered by small tubercles uniformly arranged, marked by smooth grooves.

Except the Priabonian of Hungary, this species has been recorded from the early Eocene (Ypresian) of Gecchelina di Monte di Malo (Vicenza), Vestenanova and Zovo di Bolca (Verona); from the late Eocene (Priabonian) of Campolongo di Val Liona and San Feliciano Hill (Vicenza); and from the early Oligocene of Soghe and Bernuffi di Montecchio Maggiore (Vicenza) (^{Beschin et al., 2007}, ²⁰¹⁵, ²⁰¹⁶, ²⁰¹⁸; ^{De Angeli and Beschin, 2008}; ^{De Angeli et al., 2010b}).

4. Conclusions

The previous reports of decapod crustaceans from the late Eocene of San Feliciano hill include anomurans [Galathea berica^{De Angeli and Garassino, 2002}, Acanthogalathea parva^{Müller and Collins, 1991}, A. feldmanni^{De Angeli and Garassino, 2002}, Palaeomunida defecta^{Lőrenthey, 1901}, P. multicristata^{De Angeli and Garassino, 2002}, Sadayoshia pentacantha (^{Müller and Collins, 1991}), Beripetrolisthes mulleri^{De Angeli and Garassino, 2002}, Eopetrolisthes striatissimus (^{Müller and Collins, 1991}), Lobipetrolisthes blowi^{De Angeli and Garassino, 2002}, Longoporcellana lobata^{De Angeli and Garassino, 2002}, Petrolisthes bittneri^{De Angeli and Garassino, 2002}, Pisidia dorsosinuosa^{De Angeli and Garassino, 2002}, Spathagalathea minuta^{De Angeli and Garassino, 2002}], brachyurans (Eogarthambrus guinotae^{De Angeli, Garassino and Alberti, 2010a}, Phlyctenodes dalpiazi^{Fabiani, 1911}, Spathanomus felicianensis^{De Angeli, 2016}; Caporiondolus bericus^{De Angeli, 2016}), achelata (Palinurellus bericus^{De Angeli and Garassino, 2014}), and isopods (Sphaeroma gasparellai^{De Angeli and Lovato, 2009}) (^{Fabiani, 1911}; ^{De Angeli and Garassino, 2002}, ²⁰¹⁴; ^{De Angeli and Lovato, 2009}; ^{De Angeli et al., 2010a}; ^{De Angeli, 2016}). Moreover, a carapace of Lobipetrolistes blowi with isopod (bopyrid) infestation was recorded by ^{Ceccon and De Angeli (2013)}.

Three new brachyurans Bericirinia bretoni n. gen., n. sp., Orgianocarcinus bericus n. gen., n. sp. and Actaeites lobatus^{Müller and Collins, 1991}) increase the knowledge of the decapod assemblage of San Feliciano hill. The fossiliferous level which preserves the decapod crustaceans is rich of coralline algae, corals, rare molluscs, pointing out the presence of a coral reef during the late Eocene on the southeastern side of Monti Berici (^{De Angeli and Beschin, 2004}; ^{Beschin et al., 2018}). Some species recorded in the decapod assemblage of San Feliciano hill were previously reported from the late Eocene of Hungary by ^{Müller and Collins (1991)}.