Cretopseudopsis maweii, Liu & Tihelka & Tian & Huang & Cai, 2020

Liu, Yuchu, Tihelka, Erik, Tian, Li, Huang, Diying & Cai, Chenyang, 2020, First fossil pseudopsine rove beetle from mid-Cretaceous Burmese amber (Coleoptera: Staphylinidae: Pseudopsinae), Zootaxa 4885 (1), pp. 76-82 : 77-80

Cretopseudopsis maweii sp. nov.

Figs. 1–3

Type material. Holotype: NIGP173462 , female.

Locality and horizon. Noije Bum Hill amber mine, Hukawng Valley, Kachin State, northern Myanmar; late Albian to early Cenomanian (mid-Cretaceous).

Etymology. The new species is named after Mr. Wei Ma, amber collector who kindly donated the holotype of the new species.

Diagnosis. As for the genus with additional characters: body length 5.25 mm; antennomere 1 broad and somewhat compressed; postero-medial part of frons and whole vertex elevated and dome-shaped, pronotum with five carinae arranged as in Figs 1A and 2C .

Description. Body elongate, moderately flattened. Body length 5.25 mm from clypeus to abdominal apex, body width 1.43 mm across elytra at broadest point. Body subglabrous, dark brown.

Head 1.40 mm long (including mandibles), broadest at eyes. Mandibles strong and elongate. Maxillary palps elongate, 4-segmented, reaching to the base of the fourth antennomere. Maxillary palpomere 1 scarcely longer than wide; palpomere 2 gently arching, broadest apically, 4.8 times longer than the preceding segment; palpomere 3 broadest apically, 0.7 times the length of the preceding segment; maxillary palpomere 4 at base approximately 0.5 times the width of the apex of the preceding segment, broadest medially, 1.9 times longer than the preceding segment. Labial palp 3-segmented, palp 3 longest, 1.3 times as long as the preceding segment ( Fig. 2B ). Apical margin of clypeus approximately semi-circular, strongly projecting ( Fig. 2A ). Frontoclypeal suture absent. Antennal insertions concealed from above, separated from eyes by approximately 0.5 times of eye length. Antennae incomplete, with only four complete basal segments preserved. Antennomere 1 broad, somewhat compressed laterally; antennomere 2 thinner, 0.7 times the length of the preceding segment; antennomere 3 strongly elongate, broadest apically, 2.1 times the length of the preceding segment; antennomere 4 0.7 times the length of the preceding segment; antennomere 5 apparently incomplete. Antennomeres 1–4 generally glabrous, but each with a single elongate and erect apical seta. Eyes large, multifaceted, lacking interfacetal setae and occupying approximately third of the head length. Ocelli not present. Temples short, less than half of eye length. Subocular carinae absent. Dorsum of head with dense deep punctation locally forming elongate pits, but lacking carinae. Postero-medial part of frons and whole vertex elevated and dome-shaped. Head posteriorly with elongate neck region narrowing towards the thorax, neck at narrowest point representing 0.4 times of head width across eyes.

Pronotum 0.9 mm long, 1.31 wider than long; as wide as elytra at broadest point. Anterior margin of pronotum straight. Lateral margins of pronotum smoothly rounded such that pronotum is broadest medially, margin not serrated. Pronotum dorsally with five carinae: a single medial carina running from anterior quarter of pronotum to posterior margin; two submedial carinae of equal length as single medial carina, curving medially in their anterior third; two lateral carinae running from anterior to posterior margin, running along the margin of pronotum. Pronotal disc glabrous, smooth. Posterior pronotal angles obtuse. Posterior margin of pronotum with a medial process, such that pronotum is longest medially. Protrochantins barely visible. Scutellum not visible. Prosternum rather smooth, with a medial longitudinal costa. Procoxae subcontiguous, narrowly separated by subtriangular elongate prosternal process. Procoxae longitudinal, approximately twice as long as wide. Mesocoxae longitudinal, about twice longer than wide, separated by posterior process of the mesoventrite. Mesoventrite carinate mid-longitudinally, posterior process equally wide throughout, truncate apically. Metacoxae subcontiguous, subtriangular, longer than wide; metacoxal plates developed.

Legs long, slender, setose ( Fig. 3 ). All femora robust, broadening towards apex. Tibiae slender, at most half of femora width, lacking longitudinal grooves or carinae, with two apical spurs shorter than basal tarsomere. All tarsi 5-segmented. Tarsomere 5 longer, as long or slightly longer than tarsi 1–4 together, basal 4 tarsomeres each with a group of erect setae at apex. Claws simple.

Elytra short, 1.00 mm long, 1.19 times wider than their combined length, party distorted by compression in holotype. Elytral disc sculptured with each elytron possessing 5 longitudinal carinae and rows of circular punctures separated by approximately their length. Posterior margin of elytra sinuate, with lateral portion deeply incised and an approximately medial rounded projection ( Fig. 2D ). Epipleura broad, complete. Presence of hind wings cannot be determined.

Abdomen elongate, gradually tapering posteriorly, with six ventrites. Intercoxal carina present on ventrite 1. Tergites 3–7 each with one pair of paratergites. Tergites lacking carinae, with setose rows apically. Abdominal intersegmental membranes with 'brick-wall' pattern. Stridulatory file on lateral tergal sclerite IX, if present, not visible.

Female. Stylus not visible; gonocoxites separated posteriorly, apical region with numerous long setae, posterior margin rounded.

Male unknown.

Figures

FIGURE 1. General habitus of Cretopseudopsis maweii gen. et sp. nov. (holotype, NIGP173462). A, dorsal view; B, ventral view.

FIGURE 2. Morphological details of Cretopseudopsis maweii gen. et sp. nov. (holotype, NIGP173462), A, head in dorsal view; B, head in ventral view; C, head and pronotum in dorsal view; D, elytra and abdominal base in dorsal view; E, thorax in ventral view; F, female abdominal apex. Abbreviations: a1–4, antennomeres 1–4; ec, elytral carinae; ey, eye; lp3, labial palpomere 3; lpc, lateral pronotal carina; ltsIX, lateral tergal sclerites IX; mp4, maxillary palpomere 4; mpc, medial pronotal carina; msfe, mesofemur; msti, mesotibia; nc, neck; pfe, profemur; ps, prosternum; pti, protibia; smpc, submedial pronotal carina; te, tergite. Scale bars: 200 μm (A, B, D), 400 μm (C, E, F).

FIGURE 3. Morphological details of Cretopseudopsis maweii gen. et sp. nov. (holotype, NIGP173462) legs, A, protarsus; B, mesotarsus; C, metathoracic leg. Abbreviations: ts, tibial spurs; cl, claws; msti, mesotibia; mtta, metatibia 5; mtti, metatibia; pta1–5, protarsomeres 1–5; msta1–5, mesotarsomeres 1–5. Scale bars: 100 μm (A, B), 200 μm (C).