Limnomma Li & Cai, 2021

Li, Yan-Da, Tihelka, Erik, Pang, Hong, Huang, Di-Ying & Cai, Chen-Yang, 2021, Limnomma, a new genus of Ommatidae from the Middle Jurassic Daohugou beds (Coleoptera, Archostemata), Deutsche Entomologische Zeitschrift 68 (2), pp. 299-308 : 299

Genus Limnomma Li & Cai gen. nov.

Type species.

Limnomma daohugouense sp. nov.

Etymology.

The generic name is derived from the Greek “limne”, meaning lake, referring to its habitats around the Daohugou palaeolakes, and the generic name " Omma ", the type genus of Ommatidae . The name is neuter in gender.

Diagnosis.

Head elongate, without distinct protuberances. Antennae subfiliform; antennomere 3 more than twice as long as 4. Antennal grooves absent. Gula sutures long, almost reaching posterior edge of head. Pronotal disc subtrapezoidal, with maximum width near base; lateral edges dentate. Elytra with distinct explanate epipleura; each epipleuron with only two rows of window punctures. Abdominal ventrites abutting; ventrite 5 with a slightly raised circular non-tuberculate region.

Remarks.

The circular non-tuberculate region on ventrite 5 is the most important character differentiating Limnomma from all other extant or extinct ommatids. The shape of head, prothorax, and elytral epipleura could serve as additional characters differentiating Limnomma from other Brochocoleus -like fossils.