Burmoptarthrini, Legalov, 2025

Legalov, Andrei A., 2025, First record of the subfamily Brenthorrhininae (Coleoptera, Nemonychidae) in Cretaceous Kachin amber, Zootaxa 5715 (1), pp. 225-235 : 226

Burmoptarthrini trib. nov.

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Type genus. Burmoptarthrus gen. nov.

Description.Body large (6.0 mm), subflatened dorsally, moderately sclerotized and covered with dense semierect hairs; head capsule strongly constricted behind eyes; rostrum thin and long; labrum subrectangular, transverse, free; mandibles small, not exodontous; place of antennal insertion not extended; antennae not geniculate, inserted laterally in basal part of rostrum; club not compact, its three segments free; eyes elliptical, strongly protruding from head; temples short; gular suture double; pronotum bell-shaped, weakly flattened, coarsely punctate and granulated; lateral margins of pronotum granulated; scutellum large and transverse; elytra quite wide, coarsely punctate and granulated, with greatest width behind middle; weakly punctostriate; striae indistinct; scutellar striole distinct; epipleura wide; precoxal portion of prosternum shorter than procoxal cavity length; postcoxal portion longer than precoxal portion; procoxal cavities located closer to apical margin, rounded and contiguous; mesocoxal cavities closed, rounded and separated; abdomen flattened, with ventrites free; ventrite 1 subequal to ventrite 2; trochanters not separating femora and coxae; femora without teeth; tibiae almost straight, without mucro and with two apical spurs; tarsi pseudoquadrisegmented; tarsomere 1 wide-conical; tarsomeres 2 and 3 conical-bilobed; tarsomere 5 long and narrow; claws free, strongly divergent, without teeth at base.

Diagnosis. The subfamily Brenthorrhininae consists of three Mesozoic tribes Eccoptarthrini , Brenthorrhinini and Distenorrhinini ( Gratshev & Legalov 2014). The new tribe differs from three others in having the head capsule strongly constricted behind the eyes, eyes protruding strongly, the coarsely punctate and granulated pronotum and head, as well as granulated lateral margins of the pronotum. The procoxae are located closer to the apical margin of the prosternum similar to these in the tribe Eccoptarthrini . However, the tribe Burmoptarthrini also differs from the Eccoptarthrini in having small mandibles and bilobed tarsomeres 2 and 3. It can also be distinguished from the tribes Brenthorrhinini and Distenorrhinini by the location of the procoxae and the antennal insertion in the basal part of the rostrum.

Remarks. The new tribe has been placed in the family Nemonychidae based on the free labrum, the double gular suture, non-geniculate antennae, free abdominal ventrites and tibiae with spurs. It belongs to the subfamily Brenthorrhininae based on the procoxae being located closer to the apical margin of the prosternum.