Tenuosmylus, Wang & Liu & Ren, 2009

Wang, Yongjie, Liu, Zhiqi & Ren, Dong, 2009, A New Fossil Lacewing Genus and Species from the Middle Jurassic of Inner Mongolia, China, Acta Palaeontologica Polonica 54 (3), pp. 557-560 : 557-558

Genus Tenuosmylus nov.

Etymology: The new genus name is a combination of the Latin tenuis (meaning, “narrow, slim”) and osmylus (type genus of Osmylidae ). The gender is masculine.

Type species: Tenuosmylus brevineurus sp. nov.

Diagnosis.—Forewing elongated, trichosors present at outer and posterior margins. Costal cross−veins simple and unforked distally, veinlets dense near the apex. Radial cross−veins numerous, arranged irregularly and not forming a gradate cross−veins. Presence of at least four presectoral cross−veins, however, probably more existing. Separation of Ma at approximately one−third of wing length with first branch of Rs nearly at middle of wing. Rs with 6–7 branches. Mp forks close to wing base. Cu1 with pectinate branches from middle to terminal end, interlinked by veinlets. Cu2 shorter than Cu1, nearly half as long as Cu1 and with four pectinate branches. Hind wing resembles forewing, but Cu single branch, originating at wing base and bearing many pectinate branches.

Remarks.—The new genus is most similar to Enodinympha regarding comparison of forewing venation. The two genera are also from the same locality and are of the same geological age. However, the new genus can easily be differentiated by the short Cu 2 in its forewings. Venation is generally fixed in Osmylidae and substantial variation is usually present in only higher taxa. Therefore, we consider it reasonable to erect a new genus for this fossil osmylid instead of merely treating it as a new species of previously described genera.

Stratigraphic and geographic range.—The genus is from the Middle Jurassic of Inner Mongolia, China.

Key to the fossil genera of Gumillinae

Hindwing: presectoral cross−veins less than three and separation of Ma from Rs close to wing base............................ Nilionympha Hindwing: presectoral cross−veins more than three or separation of Ma from Rs at one−third of wing length............................... 2 Rs branches number less than 10, generally 5–7.................... 3 Rs branches more numerous, greater than 10...................... 5 Forewing: Cu branches of equal length, Cu1 forming bifurcate forks without pectinate branches................................. Nuddsia Forewing: Cu branches of unequal length, Cu1 forming pectinate branches........................................................ 4 Forewing: Cu1 branches deeply forked and interlinked by veinlets. Hindwing: Cu long and of equal length to Mp2........... Epiosmylus Forewing: Cu1 branches simple and without interlinking veinlets. Hindwing: Cu short, only half the length of Mp2.....................

............................................ Tenuosmylus gen. nov. Forewing: narrow costal space near apex, Cu1 with complicated branches distally, interlinked by veinlets................... Enodinympha Forewing: broad costal space near apex, Cu1 with pectinate branches, without interlinking veinlets............................. Nymphites