Malthodes (Libertimalthodes) headsi, Fanti, 2021

Fanti, Fabrizio, 2021, Two new Malthodes and a new Podistra from Eocene Baltic amber (Coleoptera, Cantharidae), Baltic Journal of Coleopterology 21 (1), pp. 1-9 : 1-9

Malthodes (Libertimalthodes) headsi sp.

nov.

( Figs. 3 - 5 )

Holotype. Male, in Baltic amber, deposited under accession number INHSP-18001.

Type locality. Poland, Baltic Sea coast, Gdańsk city area, Wisła River estuary.

Type horizon. Middle Eocene: Lutetian (47.8–41.2 Mya) to late Eocene: Priabonian (37.8–33.9 Mya).

Fanti F.

Differential diagnosis. The last maxillary palpomere globular and distally pointed, the long elytra and the last urites little differentiated, allow this taxon to be abscribed to the genus Malthodes and its subgenus Libertimalthodes ( Fanti & Michalski 2018; Fanti 2019c; Kupryjanowicz & Fanti 2019). The species is easily distinguishable by the last sternite elongated, concave in the centre with at the sides a lobe bent upwards.

Description. Adult, winged, slender. Male defined on the basis of the last sternite elongated and with the sides apically bent upwards. Body length: about 4.0 mm, elytra 3.0 mm. Entirely dark brown.

Head not completely exposed, rounded, wide, almost smooth. Eyes large, rounded, convex, inserted laterally and in the upper part of the head; interocular dorsal distance about 3.1 times greater than eye diameter. Mandibles not well visible. Maxillary palpi 4-segmented; first palpomere short and robust, second elongated, third shorter than second, fourth globular and distally pointed. Labial palpi 3-segmented; last palpomere globular and pointed. Antennae presumably 11-segmented, filiform, inserted close to the eyes, slightly pubescent with numerous short setae; scape club-shaped, very robust and enlarged apically; antennomere II short, about 2.1 times shorter than scape; antennomeres III– VI subequal, filiform and very elongated. Pronotum transverse, narrower than head; surface almost flat, equipped with very short setae, apical margin slightly rounded and bordered; basal margin straight and bordered; sides straight and slightly bordered, propleura rounded and wide. Scutellum triangular. Elytra wider than pronotum, parallel-sided, rounded apically, very elongate, surpassing the last abdominal segments, strongly wrinkled, with semi-recumbent short setae. Hind wings transparent, almost completely covered by the elytra. Legs relatively short, rather robust; coxae robust and very elongated; trochanters elongated and rounded apically; femora robust, subcylindrical, slightly curved, equipped with many setae; tibiae shorter than femora especially the metatibiae, cylindrical, thin, without spurs at apex and equipped with setae; tarsal formula 5-5- 5; tarsomeres slender; tarsomere I elongated; tarsomere II about 1.3 times shorter than I; tarsomere III slightly shorter than II and sturdier; tarsomere IV strongly bilobed, with curved lobes; tarsomere V elongated and flat; claws simple, without lobes or teeth. Metasternum squadrate and robust; abdominal segments transverse, short, with sparse setae; last urotergite and penultimate urosternite very large and wide; last urosternite obovate, elongate, concave in the middle, with two short lobes strongly bent upwards at apex ( Fig. 5 ).

Female unknown.

Etymology. Named in honour of my friend, the great palaeontologist and entomologist Sam W. Heads (Illinois Natural History Survey, University of Illinois at Urbana-Champaign, USA).

Syninclusions. Very few botanical remains and air bubbles.

Remarks. The amber piece is transparent, measures 35 x 11 mm and shows the apex much thinner. The right metatibia is detached between the femur and tibia but still present; the right antenna is preserved up to the second antennomere and part of the third, and the left antenna is preserved up to the sixth antennomere.

Figures

Fig. 3. Malthodes (Libertimalthodes) headsi sp. nov. INHSP-18001 in Baltic amber. Holotype, dorso-lateral view, bar = 1.0 mm

Fig. 4. Malthodes (Libertimalthodes) headsi sp. nov.

Fig. 5. Malthodes (Libertimalthodes) headsi sp. nov. INHSP-18001 in Baltic amber. Drawing of last urites (lateral view)