Gonialaena groehni, Nabozhenko & Bukejs & Telnov, 2019

Nabozhenko, Maxim V., Bukejs, Andris & Telnov, Dmitry, 2019, Gonialaenini, a new tribe of Lagriinae (Coleoptera: Tenebrionidae) from Eocene Baltic Amber, Zootaxa 4565 (2), pp. 253-260 : 254-257

Gonialaena groehni sp. nov.

http://zoobank.org/ 7437512D-27AB-48AB-B532-402EBA6B81D7

( Figs 1–9 )

Type material. Holotype adult ♀: “GPIH 4959, coll. Gröhn 8589”, deposited at the Center of Natural History (CeNak) (formerly Geological-Paleontological Institute and Museum, GPIH) of the University of Hamburg, Germany. Rather complete beetle inclusion (apical tarsomeres of left mesotarsus missing) with partially exposed genitalia, included in transparent yellow piece of amber with dimensions 55×33× 13 mm. Syninclusions: one small indet. Formicidae (Hymenoptera) specimen, one indet. Nematocera (Diptera) specimen, one strongly damaged specimen of indet. Insecta, a few stellate Fagaceae trichomes, and a few small pieces of organic material.

Type strata. Baltic amber, mid-Eocene to Upper Eocene, Prussian Formation, Priabonian, ca. 37.2–33.9 Ma.

Type locality. Baltic Sea coast, Yantarny settlement (formerly Palmnicken), Kaliningrad region, Russia .

Etymology. The species is named in honour of Carsten Gröhn (Glinde, Germany) who provided the specimen for examination.

Differential diagnosis. See comparison of the genus Gonialaena gen. nov. above.

Description. Total body length about 9.1 mm; body elongated, slightly convex dorsally; unicolorous dark brown.

Head prognathous; apical maxillary palpomere securiform; eyes large, transverse, oval, slightly prominent; antennae of 11 antennomeres, filiform, moderately long, reaching basal quarter of elytra, evenly covered with sparse, erect to semierect simple trichoid setae; scape markedly wider than pedicel; pedicel short, about 0.6× as long as antennomere 3, antennomeres 3–10 elongate, subequal in length, antennomeres 8–10 slightly dilated apically, antennomere 11 spindle-shaped, 1.7× as long as wide; relative length ratios of antennomeres 1– 11 equal to?-5-9-9-9-9-9- 9-9-9-10.

Prothorax. Pronotum nearly circular, 1.1× as wide as long, widest medially. Lateral margins widely rounded, emarginate at base; anterior margin rounded; posterior margin nearly straight; anterior and lateral margins not beaded, posterior margin apparently narrowly beaded; anterior angles obsolete, vaguely expressed, posterior angles distinct, orthogonal; disc flattened, without impressions; pronotal punctation minute and dense, punctures sparser on disc than laterally; disc sparsely covered with dark erect setae of various lengths (longer setae are sparser); prothoracic hypomera finely sparsely punctate and covered with short erect setae; prosternum covered with suberect setae, before procoxal cavities much longer than one diameter of a procoxal cavity; prosternal process slightly convex, not protruding, narrow, about 0.3× as wide as procoxal diameter.

Pterothorax. Elytra elongate-oval, weakly convex dorsally, with apex prolonged, nearly mucronate; humeri rounded; each elytron with 10 indistinct striae of round coarse punctures; interstriae slightly convex, with fine punctation; sparsely covered with two types of setae: longer erect and shorter suberect ones. Epipleura wide anteriorly, gradually narrowing posteriorly, reaching elytral apex, finely densely punctate. Prohypomera, meso- and metaventrite with delicate, moderately sparse punctation; mes- and metepisternum with small and distinctly denser punctures; covered with short, fine semierect setae. Metaventrite with shallow median impression in basal half and with longitudinal sulcus posteromedially.

Abdomen finely and sparsely punctured (ventrites 4 and 5 with denser punctation), covered with short, suberect setae; narrow intersegmental membranes present between 3–5 abdominal ventrites; ventrite 5 with apical margin rounded; relative length ratios of ventrites 1–5 equal to 20-14-11-8 -13 (medially). Ovipositor of lagrioid type ( Tschinkel & Doyen 1980): with long cylindrical finger-like lobe 4 of the coxite and terminal position of long cylindrical gonostyles.

Legs long, slender, covered with sparse setae of two types and delicate punctation. Procoxal cavities closed. Mesotrochantine exposed. Procoxae globose; mesocoxae oval, longitudinal; metacoxae narrowly oval, transverse; all coxae distinctly not contiguous. Femora unarmed, without teeth, profemora slightly clavate, meso- and metafemora nearly parallel-sided, metafomora distinctly longer than mesofemora. Tibiae almost straight, nearly parallel-sided, narrow, slightly shorter than femora, with two short spines apically, covered with two types of setae: oblique short dense erect ones and 6-8 very long erect setae on outer margin. Tarsi long, but shorter than tibiae, with dense setation on plantar surface; penultimate tarsomere not bilobed or widened, insertion of terminal tarsomere is central according to the face of slightly cupuliform penultimate tarsomere; metatarsus about 1.4× as long as protarsus; relative length ratios of protarsomeres 1–5 equal to 8- 4-4-4-11; relative length ratios of metatarsomeres 1–4 equal to 20-11-10-15. Claws thin, free, simple.

Figures

FIGURES 1–2. Gonialaena groehni gen. et sp. nov., holotype: 1—habitus, dorsal view; 2—habitus, ventral view. Scale bars represent 2 mm.

FIGURES 3–7. Gonialaena groehni gen. et sp. nov.: holotype: 3—right antenna, dorsal view; 4—left antenna, ventral view; 5—elytral pubescence in apical one-third; 6—right protibial, dorsal view; 7—apical part of ovipositor. Abbreviations: a, bantennomere 1, c—outer apical spines of tibia, d—lobe VI of coxite, e—gonostyli. Not reproduced to the same scale.

FIGURES 8–9. Gonialaena groehni gen. et sp. nov.: holotype: 8—details of forebody, dorsal view; 9—details of abdomen and metathorax. Scale bars represent 1 mm.