Gnathosyne akkolkensis Ponomarenko, 1969

Yan, Evgeny V., Beutel, Rolf G. & Ponomarenko, Alexander G., 2017, Ademosynidae (Insecta: Coleoptera): A new concept for a coleopteran key taxon and its phylogenetic affinities to the extant suborders, Palaeontologia Electronica 5 (8), pp. 1-22 : 9-10

Gnathosyne akkolkensis Ponomarenko, 1969 G. akkolkensis : Ponomarenko, 1969, p. 129

Figure 3.1 , Figure 4.1

Material. Holotype: PIN 2496 /7, beetle lacking large parts of antennae, legs and abdominal apex; Eastern Kazakhstan, Saur mountain , Kenderlyk; Lower Jurassic, Tologoy Fm.

Revised description. Head transverse, 1.5 times as wide as long. Mandibles very closely spaced ( Figure 4 , md). Eyes twice as long as parietals ( Figure 4 , c.e). Antennal insertions elevated, closer to inner ocular margins than to each other. Scape ( Figure 4 , sc) equal to lengths of quadrangular 2 nd and 3 rd antennomeres; 4 th antennomer only slightly longer than scape; antennomeres 1-3 with fine longitudinal sulci.

Prosternal intercoxal process widens apically. Metaventrite as long as width at posterior margin, which is twice as wide as anterior margin. Mesoventral cavity small, rhomboid ( Figure 4 , ms.p). Pro- and mesofemora slightly thickened; tibia widened distally ( Figure 4 , fm1, tb1). Intercoxal process of first visible abdominal sternite weakly elevated. Ventral side of head and pronotum covered with small punctures merging into transverse wrinkles, rest of ventral body surface with more widely spaced small punctures. Most parts of dorsum with sparse punctures, almost appearing glabrous. See measurements in the Table 1.

Remarks. Here we interpret a pair of S-shaped lines close to the apex of the prosternal intercoxal process as fine sulci on the back side of the pronotum. An alternative interpretation as a propleural closure of the procoxal cavities appears less likely as the procoxal cavities are posteriorly more or less widely open in all other genera of † Ademosynidae .

Figures

FIGURE 3. Genera of Ademosynidae family, habitual photos. 1, Gnathosyne akkolkensis Ponomarenko, 1969, holotype, PIN 2496/7 counterpart. 2, Ademosyne kirgizica Ponomarenko, 1969, holotype PIN 2096/1369. 3, 4, A. kirgizica Ponomarenko, 1969 paratype PIN 2555/1696 print and counterprint. 5, A. bacca Ponomarenko, 1969, holotype PIN 2240/310. 6, A. bacca Ponomarenko, 1969, paratype PIN 2240/294. 7, A. ellyptica Ponomarenko, 1969, holotype PIN 2240/224. 8, Cephalosyne capitata Ponomarenko, 1969 holotype PIN 2240/302. Scale bars equal 1 mm.

FIGURE 4. Genera of Ademosynidae family, line drawings. 1, Gnathosyne akkolkensis Ponomarenko, 1969, holotype, PIN 2496/7 counterpart. 2, Ademosyne kirgizica Ponomarenko, 1969, holotype PIN 2096/1369. 3 A. kirgizica Ponomarenko, 1969, paratype PIN 2555/1696 print and counterprint. 4, A. bacca Ponomarenko, 1969 holotype PIN 2240/310. 5, A. bacca Ponomarenko, 1969, paratype PIN 2240/294. 6, A. ellyptica Ponomarenko, 1969, holotype PIN 2240/224. 7, Cephalosyne capitata Ponomarenko, 1969, holotype PIN 2240/302. Scale bars: 1 mm. Label abbreviations: c.e – compound eye; crd – cardo; cx.r – coxal rests; cx1, 2 – pro- and mesocoxae; ep – epipleura; epm2 – mesepimeron; fm1 – profemur; gul – gular plate (gula); i.p1 – prosternal intercoxal process; l.d – pronotal longitudinal depression; l.i – lateral incixions of submentum; l.r – longitudinal ridge; md – mandibles; msc – mesoscutum; mt – mentum; ms.p – mesosternal pit; o.f – occipital foramen; par – parietal; pd – pedicellus; pl1 – propleurite; p.mt – prementum; p.t.p. – posterior tentorial pit; sc – scapus; scl – scutellum; sct – mesoscutum; s.g – gular suture; s.l2 – longitudinal suture of mesoventrite; s.l3 – longitudinal suture of metaventrite; smt – submentum; s.pc – paracoxal suture.