Trixagus parvulus, 2019

Muona, Jyrki, 2019, Throscidae (Coleoptera) relationships, with descriptions of new fossil genera and species, Zootaxa 4576 (3), pp. 521-543 : 541-542

Trixagus parvulus new species

Fig. 15

Type material. Holotype labeled: Trixagus parvulus n. sp. / HOLOTYPE / J.Muona des. 10-2015. Found from Jantarny.Another label with following data included: Baltischer Bernstein / Fundort : Balticum. Jantarny ( Russland)/ Alter : Tertiär , Eozän 28-54 Mio. Jahre/ Inklusen : Käfer , Dungmücke /www.fossilien.de. Embedded in rectangular piece Baltic Amber piece, 19 mm x 16 mm x 3 mm, sex unknown but most likely female. Age 50 My. Hirsute plant remains are present as well as a nematoceran dipteran ( Fig. 26 ). Dorsum poorly visible, specimen slightly dorsoventrally compressed, venter entirely visible. Length 2.0 mm .

Diagnosis. The presence of flattened, grooved tibiae in combination with absence of tarsal grooves places this species in Trixagus . The distinctly but not deeply emarginated eyes ( Fig. 15 ) separate T. parvulus from all known species except the extant T. dermestoides . T. parvulus is smaller, more dorsally convex, has a wider pronotum and less emarginated eyes than T. dermestoides . The Eocene fossil species T. majusculus Kovalev, Kirejtshuk & Nel is quite similar in form, but it is larger and has deeply excised eyes (Kovalev et al., 2012).

Description. Form fairly wide, pronotum convex, sides evenly rounded to hind angles ( Fig. 16 ). Elytra bulbous, with sharp, minutely punctate striae, interstices with much larger, flat, moderately dense punctation ( Fig. 17 ). Abdomen and metathorax with coarse, moderately dense punctation, hypomera with dense and coarse punctation. Antennae with stout, well-developed club, a9 and a10 transverse, a11 longer than wide ( Fig.16 ).

Etymology. One of the smallest known Trixagus species and the smallest fossil one.

Figures

FIGURE 15. Trixagus parvulus n. sp., head, frontal view. ExE = excised eyes; L = labrum.

FIGURE 16. Trixagus parvulus n. sp., ventrolateral view.

FIGURE 17. Trixagus parvulus n. sp., dorsolateral view.

FIGURE 26. Trixagus parvulus n. sp., holotype.