Protoliota paleus Poinar, Vega et Legalov, 2023

Jr., George Poinar, Vega, Fernando E. & Legalov, Andrei A., 2023, Protoliota paleus sp. nov. (Coleoptera: Silvanidae) - new long antennae beetle in mid-Cretaceous Burmese amber, Ecologica Montenegrina 62, pp. 67-78 : 68-71

Protoliota paleus Poinar, Vega et Legalov , sp. nov. ( Figs. 1-5 )

https://zoobank.org/ urn:lsid:zoobank.org:act:A2923D09-D4F1-454A-BEB7-F8280B877830

Material: Accession number B-C-59 deposited in the Poinar amber collection maintained at Oregon State University.

Description. Male. Body entire, flattened, elongate, nearly parallel-sided, 2.3 mm in length (without antennae); 5.3 times longer than wide; black with white patches on dorsum of head and pronotum, nearly hairless except for setae on protarsomeres. Head: Length 480 µm; width, 680 µm, widest at level of moderately protruding emarginate (in anterior margins) eyes; with distinct temples before abruptly constricted neck; back of head with faint medial carina; greatest eye diameter, 236 µm; ommatidia small, labrum rectangular, length, 256 µm; width, 120 µm; mandibles robust, 200 µm long; straight mandibular horns present; labial palp 3-segmented, length, 250 µm. Both palps clearly visible. Front of head bearing fine granules and a conspicuous white patch 280 µm in length and 440 µm in width. Antenna not elbowed, with 11 elongated segments; filiform, with scape more than 3 times length of pedicel; antennal grooves not observed; antennal club missing, all antennomeres similar in size except for first antennomere that is longer than the others and the second antennomere that is shorter than the others; length of antenna, 7.79 mm; lengths of the 11 antennomeres: 1, 1.8 mm; 2, 0.25 mm; 3, 0.75 mm; 4, 0.75 mm; 5, 0.75 mm; 6, 0.75 mm; 7, 0.68 mm; 8, 0.48 mm; 9, 0.55 mm; 10, 0.50 mm; 11, 0.53 mm. Pronotum somewhat barrow-shaped, widening slightly at apex with 2 small protuberances on sides; first protuberance 80 µm long, with a pointed tip; second protuberance 48 µm long, with a rounded tip; dorsum of pronotum with a very faint medial carina; elevated basal ridge anterior to the basal margin; with pair of sublateral carinae, strongly projecting anterior angles; surface largely covered by fine granules and a conspicuous central white color patch; lateral margins bearing uneven rows of small spurs. Procoxal cavities open posteriorly. Legs mostly concealed beneath body. Right proleg relatively short with profemur 640 µm long and with a sub- basal swelling; protibia 480 µm in length, with rows of thin setae becoming thicker at the apex; protarsus 140 µm long, pseudotetramerous; first three tarsomeres (especially the third) lobed, bearing long, thin setae tipped with minute glands exuding droplets (setal sex patches)(Figs.3,4); claws falcate, entire; elytra narrow, entire dorsal surface covered with a deposit that prohibits further observation although clear areas show some scutellary striae; length of elytra, 1.6 mm. Abdomen with 5 fused ventrites; tip of abdomen with short pygidium; aedeagus elongate, 182 µm in length.

Derivation of name. Specific epithet is from the Greek “palaios” = ancient.

Type locality: Myanmar (Burma), state of Kachin, Noije Bum 2001 Summit Site amber mine in the Hukawng Valley , SW of Maingkhwan (26º 20´N, 96º 36´E) .

Syninclusions: An unidentified adult beetle 1.7 mm in length.

Diagnosis. The new species differs from the type species in its smaller body size, weakly protruding eyes, long mandibles, narrower pronotum, antennae 3.4 times body length, (only about 1.9 times body length in P. antennatus ) (Cai & Huang 2019), white color patterns on the dorsum of the head and pronotum, elytra with scutellary striae and setal sex patches exuding droplets on the protarsus.

Remarks. The tips of all legs, except the right foreleg, are bent under the body and very dark, making them unavailable for study The elongate, flattened body, pseudotetramerous protarsus, head with distinct temples before the abruptly constricted neck, the elytra with scutellar striole, and filiform antennae, support placement of this species in the family Silvaniidae . Placement in the subfamily Brontinae is based on the scape being more than three times the length of the pedicel and the elongate antennae without an obvious club. The procoxal cavities opening posteriorly suggest placement in the tribe Brontini . The new species belongs to the genus Protoliota Liu, Ślipiński, Wang et Pang, 2019 based on the well developed straight mandibular horns, pseudotetramerous tarsi with lobed tarsomeres, and the pronotum with a pair of sublateral carinae and strongly projecting anterior angles.

Figures

Figure 1. Holotype male of Protoliota paleus sp. nov. in Burmese amber. Light from above. Scale bar = 900 µm.

Figure 2. Close-up of 11-segmented antennae of holotype of Protoliota paleus sp. nov. in Burmese amber. The narrow clubs are over 1.5 times the body length of the insect. Light from below. Scale bar = 270 µm.

Figure 3. Foretarsus of holotype of Protoliota paleus sp. nov. in Burmese amber. c = simple falcate claw; s = setiferous setae on third protarsomere. Scale bar = 47 µm.

Figure 4. Another angle of the third protarsome of Protoliota paleus showing the exuded rows of droplets (arrows). Scale bar = 36 µm.

Figure 5. Terminalia of holotype of Protoliota paleus sp. nov. in Burmese amber. ae = aedeagus; a = anus. Scale bar = 64 µm.