Prismognathus prossi Bartolozzi & Wan

Bartolozzi, Luca & Wan, Xia, 2006, A new species of Prismognathus Motschulsky from Xizang (Tibet), China (Coleoptera: Scarabaeoidea: Lucanidae), Zootaxa 1129, pp. 61-68 : 61-65

Prismognathus prossi Bartolozzi & Wan , new species

Type material. Holotype male, China, Xizang (Tibet), Fa­Mu­Dui, Linzhi, 27.VII.2005, local collectors (from G. Pross); allotype female, same data as holotype; 22 paratypes, same data as holotype.

Holotype (collection number 12410) and allotype (collection number 12411) deposited in the Museo di Storia Naturale dell’Università di Firenze, Sezione di Zoologia “La Specola”; 2 paratypes (1 male, 1 female) in the collection of the Institute of Zoology, Chinese Academy of Sciences, Beijing; 9 paratypes (5 males, 4 females) in Gerhard Pross’ collection (Esslingen, Germany); 11 paratypes (7 males, 4 females) in the first author’s collection (Firenze, Italy).

Holotype description. Body length (including mandibles): 32.3 mm; mandible length: 5.7 mm; maximum width of head: 9.4 mm; maximum width of pronotum (at lateral angles): 11.5 mm; elytral length: 15.3 mm; maximum width of elytra: 11.1 mm.

Body elongate, almost parallel­sided, moderately convex ( Fig. 1 ); colour dark brown or blackish­brown with bronze lustre; opaque on head, elytra and pronotum shinier. Head ( Fig. 2 ) transverse, narrower at base than at front; anterior margin concave; clypeus small and truncate; canthi pointed, projecting outwards, creating with anterior angles a subrectangular, laminar expansion ( Figs. 2, 3 ), outer margin straight. Eyes large, prominent; margin of head behind eyes about as long as eye diameter, slightly convex, subcarinate. Mandibles slightly longer than head, almost straight, curved upwards at apex in lateral view, apex sharply pointed; inner edge serrate with a series of small teeth, teeth subequal in size; dorsal surface with inward pointing carina ending in a sharp upturned tooth, tooth together with acute apex of mandible forming a bifurcate apex; inner side of mandibles concave between dorsal and internal ridges; outer side convex; mandibular surface finely rugose. Mentum transverse, trapezoidal, flat or slightly concave, opaque.

Pronotum transverse, about as long as head; anterior margin convex at middle; lateral margins convex expanding to widest point behind middle, then turning inwards, slightly concave to posterior corners; lateral angles large and obtuse, posterior angles rounded, base slightly bisinuate; surface shiny on disc, more opaque at sides.

Scutellum small, semicircular. Elytra almost parallel­sided, longer than head, mandibles and prothorax together; humeri rounded; surface shiny on disc, more opaque laterally and at apex.

Legs slender, with strong claws. Protibiae shorter than femora, almost straight, bifurcate apically, apex curved downwards, lateral margin serrate with 3–4 stronger teeth, a ventral tooth at apex near insertion of tarsus; anterior spur curved. Mesotibiae straight, with sharp lateral spine preceded by a minute one, mesotibial apex terminating in 3 acute processes. Metatibiae straight, with a minute lateral spine; apical processes less developed than on mesotibiae. Mesotibiae and metatibiae with 2 asymmetrical spurs at apex, larger spur curved distally.

Venter surface of body opaque; prothorax with sparse, appressed pubescence, setae short, golden.

Genitalia: parameres subequal in length with basal piece rounded apically; median lobe broad and short, with 2 membranous lobes; permanently everted internal sac long, slender; basal piece with long and strong internal struts, articulating on proximal end of median lobe ( Figs. 4, 5 ).

Male paratypes. Body length (including mandibles): 21.6–32.3 mm; mandible length: 2.4–5.7 mm; maximum width of head: 5.8–9.4 mm; maximum width of pronotum (at lateral angles): 7.5–11.4 mm; elytral length: 12.1–15.2 mm; maximum width of elytra: 7.8–11.0 mm.

Variability. Head transverse in large specimens to subquadrate in small specimens; anterolateral cephalic laminar expansion strong with straight outer margin in large specimens, cephalic laminar expansion less evident with slightly concave outer margin in small specimens; mandibles longer than head in large specimens, subequal in length in small specimens; apical fork stronger and more curved upwards in large specimens than in small specimens.

Female allotype and paratypes. Body length (including mandibles): 18.7–23.3 mm; mandible length: 1.2–2.1 mm; maximum width of head: 4.3–5.5 mm, maximum width of pronotum (lateral angles): 6.9–8.6 mm; elytral length: 11.2–13.4 mm, maximum width of elytra: 7.7–9.1 mm.

Body elongate, moderately convex ( Fig. 6 ); colour dark brown or blackish­brown, sometimes with bronze lustre. Head quadrate, with fine punctures, anterior margin slightly concave; clypeus small and truncate. Eyes large, prominent, canthi thin, reaching anterior third of eyes; lateral margin of head behind eyes shorter than eye diameter. Mandibles shorter than head, curved, apex simple, sharply pointed; inner margin concave, with a median tooth; dorsal margin with a long and sharp middle tooth directed anterodorsally. Mentum almost semicircular, flat or slightly concave, with fine punctures.

Prothorax about as long as head, anterior margin bisinuate, convex medially; lateral margin slightly convex and enlarged at lateral angles, then turning inwards and slightly concave at posterior angles; lateral angles large and obtuse, posterior angles more or less rounded, base slightly bisinuate or straight; surface with fine punctures.

Scutellum small, semicircular. Elytra smooth and shining, almost parallel­sided, longer than head, mandibles and prothorax together; humeri rounded; surface covered with fine punctures.

Legs slender, with strong claws. Protibiae almost straight, forked apically, apex curved downwards, lateral margin serrate, with 4–6 teeth, anterior spur curved. Mesotibiae straight, with sharp lateral spine, mesotibial apex terminating with 3 acute processes, 2 asymmetrical spurs present at inner side of apex. Metatibiae similar to mesotibiae, but lateral spine smaller.

Ventral surface of body opaque; prothorax with sparse, flattened pubescence; setae short, golden.

Genitalia: hemisternites without styli, setose; spermatheca large and rounded, pigmented ( Fig. 7 ).

Type locality. China, Xizang (Tibet), Fa­Mu­Dui, Linzhi.

Etymology. This species is dedicated to Mr. Gerhard Pross (Esslingen, Germany), who kindly sent to us his Chinese lucanid collection for study.

Remarks. This new species can be easily distinguished from all other species of the genus by the peculiar shape of canthus and anterior angle of the head, creating together a subrectangular laminar expansion, unique among all the Prismognathus species ( Figs 2, 3 ).

We have had the opportunity of studying the type specimens of other Chinese species of Prismognathus , such as P. sinensis Bomans, 1989 and P. klapperichi Bomans, 1989 from Fukien, but these species are not similar to the new one in many aspects (e. g., body colour, mandibular shape, canthus form).

Prismognathus platycephalus ( Hope, 1842) and P. nigricolor Boucher, 1996 are also recorded from China, but the shape of the head of both species is clearly different from that of P. prossi n. sp., lacking the peculiar laminar expansion of the anterolateral part of the head.

Prismognathus branczicki Nonfried, 1905 was described on a single specimen from Ou­Hou, Southwest China. The sex of the type specimen is not indicated in the paper and no illustration is given, but the length of the mandibles (5 mm on a total size of 26 mm) and their description clearly indicate that Nonfried was studying a male specimen. Mizunuma & Nagai (1994) gave a photo of the “ holotype ” of P. branczicki , but the figured specimen is a female, thus it cannot be the true type described by Nonfried. Krajcik (2003: 141) writes that the holotype of P. branczicki is in the Zoological Museum of the Humboldt University in Berlin, but the first author did not find it during his visit to Berlin in September 2001. Regardless, Nonfried’s description clearly indicates that P. branczicki is similar to P. davidis Deyrolle, 1878 , which is totally different from the new species described here. Prismognathus davidis has the maximum width of the head at the anterior angles, which are acute, while P. prossi n. sp. has the maximum width of the head at the canthi, and the anterior angles are obtuse. Benesh (1943) identified a female from Sichuan as P. branczicki (incorrectly calling this specimen the allotype), but this identification requires further investigation.

In the last few years new taxa of Prismognathus have been described and illustrated from the northern regions of India, Vietnam, and Myanmar ( Boucher 1996, Ikeda 1997, Nagai 2000, Baba 2004, Nagai 2005), and from China (Yunnan) ( Bartolozzi 2003), but they all quite differ from P. prossi n. sp. in the shape of head and mandibles.

We believe it useful to update the checklist of species and subspecies of Prismognathus given by Bartolozzi (2003), including the taxonomic changes made by Nagai (2005).

Figures

FIGURES 1 – 7. Prismognathus prossi n. sp.: 1 — male, dorsal view (length 32.3 mm); 2 — male head, dorsal view; 3 — male head, lateral view; 4 — aedeagus, ventral view; 5 — aedeagus, lateral view; 6 — female, dorsal view (length 22.0 mm); 7 — female genitalia. Scale bar: 1 mm. Abbreviations: AG, accessory gland; BP, basal piece; HS, hemisternite; MO, median oviduct; PA, paramere; PE, penis; PES, permanently everted sac; S, spermatheca; SG, spermathecal gland; ST, strut.