Cacomorphocerus obstinatus, Parisi & Fanti, 2020

Parisi, Francesco & Fanti, Fabrizio, 2020, Baltic amber: A new Cacomorphocerus Schaufuss, 1892 with two specimens preserved in a single piece, and four new Malthodes Kiesenwetter, 1852, Zootaxa 4778 (3), pp. 546-560 : 547-549

Cacomorphocerus obstinatus PARISI & FANTI sp. nov.

( Figs. 1–2 )

Description. Holotype: Sex undefined, adult, winged. Body length 6.8 mm (head folded); elytra 4.8 mm; pronotum 1.0 mm; antennae 3.2 mm. Head brown, pronotum reddish-brown, elytra black-dark brown, legs and antennae reddish-brown.

Head prognathous, slightly covered by pronotum. Eyes small, rounded, inserted laterally to the head. Antennae 12-segmented, short, slightly surpassing the humeral zone of the elytra, filiform with antennomeres II–IX slightly modified, insertion rather far to upper margin of eyes; scape robust, not club-shaped; pedicel short, almost globular, approximately 1.5 times shorter than scape; antennomere III moniliform/globular, slightly longer than antennomere II; antennomeres IV–IX, short, robust, enlarged in the middle; antennomeres X–XI filiform, longer than previous ones; antennomere XII filiform, with rounded apex, longer than antennomere XI; all antennomeres slightly pubescent equipped with short and erected setae. Pronotum slightly transverse, wider than the head, sparsely covered with shallow punctation, the surface concave in the middle, anterior margin slightly rounded and not bordered, posterior margin straight and slightly bordered, sides strongly rounded, anterior and posterior corners rounded and without denticles. Scutellar shield triangular-shaped with rounded apex. Elytra long, slightly surpassing the last abdominal segment, parallel-sided, slightly rugose and equipped with raised short setae, narrower than pronotum, apices rounded. Hind wings not visible and thus completely covered by elytra. Last tergite rounded. Legs rather robust, not particularly long, densely pubescent with long setae; coxae robust; trochanters globular, short; femora enlarged and curved; tibiae slender, subcylindrical, thin and only slightly enlarged from the middle length to the apex, with a spur near the apex, pro- and mesotibiae shorter than pro- and mesofemora, metatibiae slightly longer than metafemora; tarsi 5-segmented; tarsomere I elongate; tarsomere II approximately 1.2 times shorter than tarsomere I; tarsomere III shorter than tarsomere II and slightly protruded at sides; tarsomere IV bilobed; tarsomere V slender; claws thin, pointed at the apex and with an acute denticle basally.

Paratype: Sex undefined, adult, winged. Body length around 7.0 mm (head folded); elytra 5.0 mm; pronotum 1.0 mm; antennae 3.3 mm. Head brown, pronotum reddish-brown, elytra black-dark brown, legs and antennae reddish-brown.

Morphologically very similar to the Holotype, mandibles elongate, thin apically and apparently dentate (with small denticles). Last maxillary palpomere securiform. Pronotum less rounded at sides but probably distorted during fossilization. Metatibiae slightly shorter than metafemora. Metasternum sub-quadrate. Ventrites strongly transverse.

Etymology. Derived from the Latin adjective obstinātus = obstinate. In reference to the fact that it seems to have been so stubborn to remain trapped in amber with two specimens.

Holotype. Sex undefined, in Baltic amber, deposited at the University of Molise (Unimol) with accession No. Unimol AAA008FP (A) . Paratype. Sex undefined, in Baltic amber, deposited at the University of Molise (Unimol) with accession No. Unimol AAA008FP (B). Both , Holotype and Paratype are preserved in the same amber piece.

Type locality. Yantarny mine, Sambian Peninsula, Kaliningrad region, Russia.

Type horizon. Middle Eocene (Lutetian) (47.8–41.2 MYA) to Late Eocene (Priabonian) (37.8–33.9 MYA).

Syninclusions. Air bubbles (some very large), stellate hairs, debris.

Differential diagnosis. Cacomorphocerus Schaufuss, 1892 has 11 or 12 antennomeres with the central ones that are more or less saucer-shaped and tendentially strongly modified ( Bukejs et al. 2019; Fanti & Pankowski 2019; Poinar & Fanti 2019; Kazantsev & Perkovsky 2020). C. obstinatus sp. nov. shows a unique feature with 12 antennomeres filiform or slightly modified. The antennomeres II–IX are only robust, rather short. Also, the genus Sucinorhagonycha Kuśka, 1996 has 12 antennomeres filiform or slightly dentate but this genus possesses claws without teeth or lobes ( Kuśka 1996; Fanti & Pankowski 2018).

Remarks. The amber piece measures 19 x 12 x 4 mm. The inclusions, both holotype and paratype, are complete but strongly ventrally covered by a white emulsion. The Paratype has also the pronotum distorted during fossilization.

Figures

FIGURE 1. Cacomorphocerus obstinatus sp. nov. in Baltic amber (UNIMOL AAA008FP AB). Holotype, dorsal view (A1); Paratype, ventral view (B1), scale bar = 1 mm.

FIGURE 2. Cacomorphocerus obstinatus sp. nov. in Baltic amber (UNIMOL AAA008FP AB). A: detail of pronotum (Holotype A), scale bar = 200 μm. B: detail of elytra (Holotype A), scale bar = 500 μm. C: detail of antenna with numbered anten- nomeres (Holotype A), scale bar = 200 μm. D: detail of antenna with numbered antennomeres (Paratype B), scale bar = 400 μm. E: detail of the left mesothoracic leg (Holotype A), scale bar = 200 μm. F: detail of claws (Paratype B) arrow shows lobe, scale bar = 50 μm. G: detail of palpi and mandibles (Paratype B), scale bar = 50 μm.