Scolytoplatypus unipilus Jordal

Jordal, Bjarte H., 2018, The smallest known species of Afrotropical Scolytoplatypus Schaufuss (Curculionidae, Scolytinae) - with unique features and an isolated phylogenetic position, ZooKeys 749, pp. 125-130 : 125

Scolytoplatypus unipilus Jordal sp. n. Figs 1-4

Type material examined.

Holotype, female: Gabon: Ivindo National Park, Ipassa, 6 km W. Makokou. GIS: 0.512, 12.802, #23 vittatol trap. Paratypes (2): same data as holotype, except one taken from Ipsenol trap. The holotype and two paratypes (" ZMBN/ENTScol4942 - ZMBN/ENTScol4944") are deposited in the University Museum of Bergen (ZMBN).

Diagnosis, female.

Typical female Scolytoplatypus with broad protibiae with transverse rows of granules and rugae, an anteromedian mycangial pore on pronotum, and a depressed triangular scutellum. Distinguished from all species in the genus by the unusually long antennal club, further from all African and Malagasy species by the small size (1.7 vs.>2.3 mm), the lack of striae on elytral declivity (and disk), by the undivided, simple setae on the metanepisternum, and the rounded hind corners of the pronotum.

Description, female.

Length 1.6-1.7 mm, 2.0 × longer than wide; colour dark brown to black, ventral side and legs brown.

Head. Eyes separated above by 3.9 × their width. Frons generally convex, slightly flattened on upper half, rounded below, with a transverse, broad, impression just above epistoma; surface smooth and shiny on lower half, reticulated and dull above, with small shallow punctures separated by 2-4 × their diameter. Vestiture consisting of scattered, short, fine setae mainly in reticulated area on upper half. Antennal club 3 × longer than funicle, densely covered by very short scale-like setae and fewer and much longer fine setae. Funiculus 5-segmented.

Pronotum 0.9 × as long as wide, sides subparallel on anterior half, constricted on posterior half, 0.9 × as wide as anterior part; surface finely reticulated with shallow punctures spaced by 1-2 × their diameter; pronotal vestiture consisting of fine short setae arising from punctures, a few longer setae scattered close to anterior margin. Mycangial pore slightly elliptical, with long yellow setae emerging, center of pore located on anterior fifth.

Elytra 1.1 × longer than wide, 1.3-1.4 × longer than pronotum; basal area notched for depressed triangular scutellum; sides of elytra straight, broadly rounded behind; striae not indicated, punctures confused, spaced on disc by 1-2 × their diameter; declivity finely rugose, strongly reticulated. Interstriae 10 weakly elevated to level of ventrite 1. Vestiture consisting of minute setae on declivity.

Legs. Procoxae separated by width of antennal club. Mesocoxae separated by width of a mesocoxa. Protibial shape typical for genus.

Ventral vestiture. Metanepisternum with relatively few, fine, simple setae.

Male.

Not known.

Molecular data.

Phylogenetic analysis based on four genes resulted in a fully resolved tree topology (Fig. 5). Different partition schemes and model selection had no influence on tree topology. Scolytoplatypus unipilus formed a maximally supported sister lineage to all other African and Malagasy species in the genus, and yet clearly separate from the Asian species. GeneBank accession numbers: COI, MG979488; EF1a, MG979489; CAD, MG979490; 28S, MG980072.

Etymology.

The Latin name unipilus is composed of the masculine adjective unus in its form uni-, meaning one, and the masculine noun pilus, meaning hair, referring to the simple, single, hair-like setae on the metanepisternum and metasternum.

Distribution and biology.

Only known from the type locality in Gabon. All specimens were collected in black flight intercept traps baited with vittatol (3) or ipsenol (1) lures.