Malthodes (Malthodes) unimol, 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 : 555-557

Malthodes (Malthodes) unimol PARISI & FANTI sp. nov.

( Figs. 9–10 , 11D )

Description. Male, winged. Body length 2.9 mm; elytra 1.6 mm; pronotum 0.3 mm; antennae 1.8 mm. Head black, pronotum and elytra dark-brown, antennae and legs brown-testaceous, without yellow spots on elytral apex.

Head exposed, transverse, rounded behind the eyes, covered by few long setae. Eyes very large, rounded, inserted in the lateral-upper part of the head. Maxillary palpi 4-segmented, with the last palpomere globular and distally pointed. Labial palpi 3-segmented, last palpomere globular and distally pointed. Antennae filiform, 11-segmented, short, reaching the middle of elytra and middle of the abdomen; antennomere I very elongate, robust, club-shaped; antennomere II approximately 1.5 times shorter than antennomere I; antennomere III as long as antennomere II; antennomeres IV–X sub-equal, longer than previous ones; antennomere XI filiform, elongate, rounded at the apex; all antennomeres densely covered by long setae. Pronotum strongly transverse, wider than the head, surface irregular and punctate, covered by few long setae, anterior margin rather straight and strongly bordered, posterior margin straight and strongly bordered, sides straight, slightly bordered and narrowed at the insertion of the anterior margin. Elytra short, robust, reaching the base of the seventh abdominal segment, slightly wider than pronotum, covered with scattered long setae, parallel-sided, rounded at apices. Hind wings transparent and only little infuscate, very long, strongly surpassing elytra and the last abdominal segment. Legs relatively short, robust, densely pubescent; coxae elongate, trochanters with rounded apex; femora slightly enlarged and not curved; tibiae shorter than femora, thin, cylindrical, with a spur at the apex; tarsi 5-segmented, pubescent; tarsomere I thin, very elongate; tarsomere II short, approximately 2.3 times shorter than tarsomere III; tarsomere III triangular-shaped and slightly shorter than tarsomere II; tarsomere IV heart-shaped, deeply bilobed and very robust; tarsomere V elongate and slender; claws simple. Metasternum sub-quadrate, with undulate posterior margin. Sternites transverse and pubescent. Penultimate tergite (tg9) elongate and broad; last tergite (tg10) in the shape of a lobe, very small, triangular-shaped and apically pointed, pubescent especially at the apex; last sternite (st9) elongate, curved, apically forked (with lobes robust and feebly incised). Aedeagus little visible. Female unknown.

Etymology. Derived from the acronym UniMol (= Università degli Studi del Molise-University of Molise), where the Holotype is now preserved. The epithet is to be treated as a noun in apposition.

Holotype. Male, in Baltic amber, deposited at the University of Molise (Unimol) with accession No. Unimol AAA007FP.

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. Few air bubbles, and debris.

Differential diagnosis. Malthodes unimol sp. nov. does not appear phylogenetically related to the other known species except, perhaps, M. immortalis sp. nov. The last sternite (st9) very elongated, slightly curved and apically forked is similar to those of Malthodes moellehavei Fanti & Damgaard, 2018 and Malthodes sucini Kuśka & Kania, 2010 from which differs by its last tergite (tg10) narrower with an apical point, and by its shorter antennae ( Kuśka & Kania 2010; Fanti & Damgaard 2018). Malthodes unimol sp. nov. is extremely similar to Malthodes immortalis sp. nov. and has the last sternite less deeply incised and less wide with the last tergite pointed apically (not pointed in M. immortalis ). Malthodes unimol sp. nov. however is considerably smaller, has shorter antennae, and has more transverse and different shape of pronotum than M. immortalis sp. nov.

Remarks. The amber piece is extremely transparent and measures 17 x 12 x 0.2 mm. The inclusion is complete with the head laterally folded, and a little ventrally white emulsion.

Figures

FIGURE 9. Malthodes (Malthodes) unimol sp. nov. in Baltic amber (UNIMOL AAA007FP). Holotype, dorsal view, scale bar = 500 μm.

FIGURE 10. Malthodes (Malthodes) unimol sp. nov. in Baltic amber (UNIMOL AAA007FP).A: Holotype, ventral view, scale bar = 500 μm. B: Holotype, detail of antennae (with numbered antennomeres), scale bar = 200 μm. C: Holotype, detail of last urites (lateral view), scale bar = 50 μm. D: Holotype, detail of last urites (lateral view), scale bar = 50 μm.

FIGURE 11. A: Malthodes (Malthodes) giannii sp. nov. Reconstruction of the last abdominal segments, scale bar = 25 μm. B: Malthodes (Malthodes) immortalis sp. nov. Reconstruction of the last abdominal segments, scale bar = 400 μm. C: Malthodes (Malthodes) marialuisae sp. nov. Reconstruction of the last abdominal segments, scale bar = 200 μm. D: Malthodes (Malthodes) unimol sp. nov. Reconstruction of the last abdominal segments, scale bar = 100 μm.