Archaeocerus uenoi Perreau, 2019

Perreau, Michel, 2019, Archaeocerus uenoi n. gen. n. sp. (Coleoptera Leiodidae Catopocerinae) from Albian / Cenomanian age amber of Myanmar, Zootaxa 4638 (4), pp. 595-600 : 596

Archaeocerus uenoi Perreau , n. sp.

Holotype presumably male: Myanmar, upper cretaceous amber deposit of the Hukawng valley , deposited in coll. M. Perreau.

Description. Length: 1.20 mm. Body elongate ( Figs. 1, 2 ), flattened ( Fig. 3 ), dark brown, the antennae, legs and mouthparts light brown.

Head without occipital carina. Antennal insertions concealed in dorsal view. Antennae with 11 antennomeres, the 8th significantly narrower than the 7th and the 9 th; the 7th, 9th and 10th without teeth ( Fig. 5 ). Gular sutures widely distant. The observation of the presence or absence of a stem on the epistomal suture is not possible on the studied specimen.

Pronotum transverse, approximately 1.4 times as wide as long, widest very close to the base, with sides regularly arcuate and convergent anteriorly ( Fig. 1 ). Surface shiny, with tiny punctures and a fine microreticulation, without transverse strigae, but with a longitudinal median impression ( Fig. 1 ). Lateral margins with a distinct gutter ( Fig. 1 ).

Elytra approximately 1.4 times as long as wide together, parallel in the two basal thirds of their length, then regularly rounded at apex. A single parasutural longitudinal stria. Punctures transversely aligned in oblique strigae and associated with short setae ( Fig. 1 ). Surface shiny, with no visible microreticulation. Marginal gutter fairly wide ( Fig. 1 ).

Flight wings present and probably functional, with nervation (veins) present near the base, reduced on the apical half, with numerous microtrichia and with ciliate margins, ( Figs. 7, 8 ).

Ventral structures. Anterior part of the prosternal surface elongated in front of the procoxae ( Fig. 2 ). Mesoventrum with a sharp and uninterrupted longitudinal median carina, the metaventrum not carinate, but with a wide and deep medial depression ( Fig. 2 ). Metaventrite and first abdominal ventrite without setose paired impressions (the white spots visible on the ventral surface on Fig. 2 are air bubbles, not setose impressions, they do not contain setae). Metacoxae clearly separate.

Legs. Tarsal formula 5-4-4. Protarsi imperceptibly dilated, with tenent setae of two kinds on the ventral face: some very long and straight, the others shorter, curved and slightly dilated at the apex ( Fig. 6 ). Mesotarsi and metatarsi undilated ( Fig. 4 ) and without tenent setae. Last protarsomere as long as the four preceding ones taken together, last meso and metatarsomeres as long as the three preceding ones taken together. Protibiae thickened in the basal half, then bearing an area lined with a dense bunch of setae on the inner margin of the apical half, in some way similar to the protibial antenna cleaner of the some Carabidae ( Fig. 6 ). Outer side of protibiae spineless, outer side of meso and metatibiae with strong spines ( Fig. 4 ).

Etymology. The name of the genus is built from the greek "Arkhaĩos": old and "cerus" from the last part of the name of the subfamily (possibly from Greek, meaning “horn”, despite Motschulsky (1870) gave no information on the origins of his generic name and there is no "horn" structure suggesting such a root). The species is dedicated to Teruhisa Ueno who provided to us the specimen.

Figures

FIGURES 1–3. Archaeocerus uenoi n. gen., n. sp., habitus. 1, dorsal side. 2, ventral side. 3, lateral side. msc=mesoventral carina, mtd=metaventral depression.

FIGURES 4–8. Archaeocerus uenoi n. gen., n. sp. 4, right legs from below. 5, detail of the head and the right antenna. 6, detail of the right foreleg. 7, left flight wing. 8, right flight wing. mp=maxillary palp; bs=protibial bunch of setae; ts=tenent setae.