Paralithomerus exquisitus, Chang, Huali, Zhang, Fan & Ren, Dong, 2008

Chang, Huali, Zhang, Fan & Ren, Dong, 2008, A new genus and two new species of fossil Elaterids from the Yixian Formation of Western Liaoning, China (Coleoptera: Elateridae), Zootaxa 1785, pp. 54-62 : 55-58

Paralithomerus exquisitus sp. nov.

( Figs. 1–10 )

Type specimen: Holotype. CNU-C-LB2006874-1, CNU-C-LB2006874-2 (part and counterpart of one specimen), almost complete impression of elaterid, housed in Key Lab of Insect Evolution & Environmental Changes, Capital Normal University, Beijing, China.

Locality and horizon. Collected from 2nd Bed of the Yixian Formation in Huangbanjigou, near Chaomidian Village, Shangyuan County, Beipiao City, Liaoning Province, China; Upper Jurassic-Lower Cretaceous.

Etymology. Specific name derived from Latin “ exquisitus ”, (meaning “exquisite”), for the striae of elytra are exquisitely preserved and elegantly lined.

Diagnosis. Head medium sized; maxillary palpi three segmented, last segment enlarged; eyes oval. Pronotum with width 1.07 times wider than long; prosternal process short. Elytra with 9 longitudinal striae, the 2nd and 3rd, 6th and 7th are united at the apical 1/4.

Description. Body subcylindrical, small sized, with length 8.5 mm, width 2.5 mm, elytron length 5.3mm; Maxillary palpi with terminal segment enlarged; Elytra with 9 distinctly longitudinal striae, the 3rd and 4th, 7th and 8th are united approximately at the apical 1/4 ( Figs. 1, 2 ).

Head sub-triangular, convex; maxillary palpi three segmented, with terminal segment enlarged; mandibles incurved, bidentate at apex; labrum small, transverse; eyes oval, medium sized ( Fig. 3 ).

Antennae filiform, incomplete with 8 preserved segments; scape robust, pedicel slightly shorter than scape and antennomere 3 together, antennomeres 4–8 progressively narrower ( Figs. 3 , 9 ).

Pronotum 1.92 times as long as head; with width 1.07 times wider than long; anterior margin arched inside, with short angles, lateral margins arcuate in front of hind angles, basal margin bisinuate, with basal pleural furrow; disc slightly convex; hind angles acute, with distinct short carina, produced laterally and posteriorly while embracing elytra bases ( Figs. 1, 4 , 9 ).

Elytra wider than prothorax, 3.62 times as long as wide; disc slightly convex, with 9 distinct longitudinal striae, the 3rd and 4th, 7th and 8th are united approximately at the apical 1/4; apex of elytra slightly obtuse ( Figs. 1 , 7 , 9 ).

Ventral surface with chin piece normally arcuate; pronotosternal suture double, widely opened anteriorly; procoxal cavities small, rounded and separated, open behind; prosternal process quite short, wedge-shaped. Mesoventrite small, with transverse sutures, mesoventral cavity circular, mesepimeron triangular, mesocoxae open to mesepimeron. Metaventrite and mesoventrite separated by distinct suture, metaventrite relatively long and flat, with longitudinal suture; metepisternum normal; metacoxal plates slender, obtusely long triangular, evenly narrowed laterally. Abdomen with 5 visible ventrites, narrowed from the base of fifth visible ventrite, apical ventrite extending beyond elytra; ovipositor slightly extended ( Figs. 2, 4–6, 8 , 10 ).

Legs with procoxa rounded, profemur slender, mesocoxa circular, much bigger than procoxa, mesotrochanter quite small, oval, metacoxa plates slender, obtusely long triangular, metatrochanter oval ( Figs. 6 , 10 ).

Figures

FIGURES 1 – 4. Paralithomerus exquisitus gen. et sp. nov., holotype. 1 — CNU-C-LB 2006874 - 1, 2 — CNU-C- LB 2006874 - 2, 3 — head, 4 — prothorax.

FIGURES 5 – 8. Paralithomerus exquisitus gen. et sp. nov. holotype, 5 — mesoventrite, 6 — hind legs, 7 — apical half of elytron, 8 — oviposotor.

FIGURES 9 – 10. Paralithomerus exquisitus gen. et sp. nov., holotype, 9 — dorsal view, 10 — ventral view.