Palaeocantharis panna, Hsiao & Li & Ren & Pang, 2021

Hsiao, Yun, Li, Yun, Ren, Dong & Pang, Hong, 2021, Morphological phylogenetics provide new insights into the classification and evolution of fossil soldier beetles from Mid-Cretaceous Burmese amber (Coleoptera: Cantharidae), Zoological Journal of the Linnean Society 193, pp. 1271-1293 : 1283-1284

† PALAEOCANTHARIS PANNA SP. NOV.

( FIGS 5–6 )

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Type material: Holotype: Female; no. CNU- COL-MA-0019; earliest Cenomanian, Hukawng Valley, northern Myanmar; deposited in the Key Laboratory of Insect Evolution & Environmental Changes, Capital Normal University in Beijing, China.

Diagnosis: As for the genus.

Description: Female. Body 5.8 mm long, 1.3 mm wide, parallel-sided, densely covered with suberect pubescence. Body yellowish brown, with abdomen lighter in colour ( Fig. 5 ). Head ( Fig. 6A, B ) 0.9 mm long, 1.1 mm wide. Vertex smooth, shallowly depressed. Eyes small, hemispherically prominent, with fine facets, interocular distance 1.8 times maximum eye diameter. Anterior margin of clypeus arcuate, frontoclypeal suture absent. Labrum membranous, partially exposed. Gular sutures close, nearly confluent. Mandibles slender, strongly curved, with a sharp tooth at two thirds of inner margin. Apical segments of maxillary palpi and labial palpi flattened, securiform. Antennae ( Fig. 5A ) serrate; scape slender, widened apically; pedicel short, cylindrical; antennomeres 3–6 triangular; relative lengths of antennomeres 3–6: 1.0:1.3:1.4:1.4. Pronotum ( Fig. 6C ) 1.2 mm long, 1.1 mm wide, circular-shape. Anterior and lateral margins arcuate, posterior margin almost straight; disc densely punctate, with pair of shallow longitudinal grooves at basal half. Scutellum parallelsided, straight at apex. Elytra ( Figs 5A , 6D ) 3.9 mm long, 1.3 mm wide, parallel-sided, densely pubescent, with distinctly elevated humeri; lateral margins of elytra slightly elevated, with complete epipleuron; each elytron with eight longitudinal costae; costal interspaces with row of rounded cells; hindwing well-developed, completely concealed beneath elytra. Abdomen ( Fig. 5B ) weakly sclerotized, with seven ventrites; first five segments broad, as wide as elytra; last two segments ( Fig. 6E ) narrower, extending beyond elytra, apical tergite bilobed, ventrite 7 abruptly narrower distally, emarginate at apex. Female genitalia ( Fig. 6E ) retracted within abdomen, with pair of palpiform gonostyli exposed. Legs ( Figs 5 , 6F ) slender; profemora strongly dilated, meso- and metafemora elongate, profemur length 0.9 mm, mesofemur 1.2 mm, and metafemur 1.9 mm; tibiae slender, nearly straight, with paired tibial spurs, protibia length 0.9 mm, mesotibia 1.5 mm and metatibia 2.0 mm; tarsal formula 5-5-5; tarsomeres 1–3 simple, tarsomere 1 longer than two times length of tarsomere 2; tarsomere 4 bilobed; claws simple, with minute dent at base.

Etymology: The specific epithet is derived from paññ ā, ‘wisdom’ in the Pali language and a Buddhist term described as the understanding of the true nature of phenomena. We chose this name because the discovery of this species provided an insight into the palaeontology of Cantharidae . It is a noun in apposition.

Figures

Figure 5. Habitus of Palaeocantharis panna: A, dorsal view; B, ventral-lateral view. Scale bars: 2.0 mm.

Figure 6. Details of body parts of Palaeocantharis panna: A, head, dorsal view; B, ditto, ventral-lateral view; C, pronotum; D, elytra; E, caudal segments of abdomen, with gonostyli indicated by a black arrow; F, tarsi of hind legs. Scale bars: 1.0 mm (A, B, D); 0.5 mm (C, E, F).