Baltacalles, Bukejs & Alekseev & Legalov, 2020

Bukejs, Andris, Alekseev, Vitalii I. & Legalov, Andrei A., 2020, A new Eocene genus of the subtribe Tylodina (Coleoptera: Curculionidae) and notes concerning local differences of Baltic amber in the Kaliningrad Region, Fossil Record 23 (1), pp. 75-81 : 76

Genus Baltacalles gen. nov.

urn:lsid:zoobank.org:act:71577B46-1637-478B-A069-62C592AE4E15

Type species

Baltacalles triumurbium sp. nov., herein designated.

Etymology

The name is formed from the Latin balticum (Baltic) and the generic name “ Acalles ”. Gender masculine.

Description

Rostrum curved, not flattened, not separated by transverse groove; antennae geniculate, inserted near middle of rostrum; funicle 7-segmented; scape shorter than funicle and not reaching eye; forehead narrow; eyes well developed, large; scutellum distinct; elytral humeri reduced; prosternum with rostral channel margined by carinae; apex of rostral channel reaching mesoventrite, margined by carina; postcoxal portion of prosternum not bounded by carinae; mesepimeron not enlarged and invisible between bases of prosternum and elytra; metaventrite shorter than abdominal ventrite 3; metepisternum narrow, subparallel; abdominal ventrites 1–5 oriented in one plane; ventrites 1–2 elongate, fused, about 2.8× as long as ventrites 3–4 combined; suture between ventrites 1– 2 shallow, not straight; abdominal process as broad as metacoxa; posterior margins of ventrites 2 and 3 straight; tibiae with large uncus and two groups of setae; femora denticulate; protibiae distally without mouth groove and row of dense erect setae (grooming device); mesotibiae without denticle in middle of exterior margin; tarsomere 5 with free claws not separated by dermal lobes.

Differential diagnosis

The new fossil genus is similar to the extant Acalles Schoenherr, 1825 but differs from it in the denticulate femora; abdominal ventrites 1–2 combined about 2.8× as long as ventrites 3–4 combined; distinct scutellum; narrow, subparallel metepisternum; not flattened rostrum; and narrow forehead.

Remarks

The geniculate antennae, elongate and fused ventrites 1–2, and ventrites 1–5 oriented in one plane suggest placement of Baltacalles gen. nov. in the family Curculionidae . The tibiae with large uncus and two groups of setae, straight posterior margins of ventrites 2–3, protibiae distally without mouth groove and row of dense erect setae (grooming device), tarsomere 5 with claws not separated by dermal lobes, antennae inserted near middle of the rostrum, and mesepimeron not enlarged and invisible between bases of prosternum and elytra, suggest placement in the subfamily Molytinae . Placement of this new fossil genus in the tribe Cryptorhynchini is based on the prosternum with rostral channel reaching middle coxae and margined by carinae, its apex reaching mesoventrite and margined by a carina, postcoxal portion of the prosternum not bounded by carinae, eyes well developed, rostrum not separated by groove, mesotibiae without denticle in middle of exterior margin, scape shorter than funicle and not reaching eye, and metaventrite shorter than abdominal ventrite 1. The new genus belongs to the subtribe Tylodina based on the metaventrite shorter than abdominal ventrite 3, abdominal process as wide as metacoxa, metepisternum narrow, and elytra with reduced humeri.