Xyloctonus niger Schedl, 1938

Jordal, Bjarte H., 2024, Integrated taxonomy, biology and biogeography of the Afrotropical genus Xyloctonus (Coleoptera, Curculionidae, Scolytinae), Deutsche Entomologische Zeitschrift 71 (1), pp. 67-84 : 67

Xyloctonus niger Schedl, 1938

Figs 9 , 12 , 15

Xyloctonus niger Schedl, 1938 d: 452.

Type material.

Syntypes: Uganda, Entebbe [0.04, 32.42], 11-II-1938, P. Chandler [NHMUK, NHMW].

Diagnosis.

Length 2.5 mm, 2.1 × as long as wide, colour black, shiny; antennal club with two visible procurved sutures; frons glabrous; anterior margin of pronotum with two raised teeth clearly longer than broad; all elytral interstriae carinate to posterior elytral margin; strial and interstrial punctures very shallow making walls of carinae rather smooth and shiny; scutellar shield a rounded button, clearly detached from the surrounding elytra; elytral suture with bulgy locking mechanism behind scutellar shield; setae on lateral metaventrite bifid.

Distribution.

Uganda.

Biology.

Known from the two collections in Uganda; the non-type series were dissected from Tabernaemontana holzkii ( Apocynaceae ) (see Menier (1974)).

Comments.

This species is very similar to X. scolytoides , but can be distinguished by the smooth and shiny interstrial carinae which is not indented along the carina wall, the glabrous frons and the consistently bifid setae on the lateral part of the metaventrite.

The Xyloctonus bimarginatus group

All species (except X. opacus and X. punctatus ) have interstriae 9 curved and continued to the elytral suture such that none of the interstriae 1-8 reaches the apical margin (Figs 1-4 ); thereof the name ' Xyloctonus bimarginatus '. In the two deviant species, the gap between the ninth interstriae and the apical margin nearest apex is so tight that interstriae 1-3 apparently reach the apical margin (Fig. 20 ). Nine species have exactly two raised teeth at the anterior margin of the pronotum, whereas another group of six species have four raised teeth along the anterior margin of the pronotum.

Species with two-spined pronotum

Figures

Figures 7 - 15. Dorsal, lateral and front view of X. scolytoides (7, 10, 13); paralectotype of X. latus (synonym of X. scolytoides) (8, 11, 14); holotype of X. niger (9, 12, 15).

Figures 1 - 5. Posterior view of elytral declivity in 1. Xyloctonus quadridens; 2. X. maculatus; 3. X. subcostatus (paratype of X. striatus); 4. X. pubifer; 5. X. scolytoides (paralectotype of X. latus). Black arrows points at the shallow furrow on the posterior side of the metatibiae, similar to mesotibiae. White arrow points to the impression of the metaventrite which receives the metafemur. Yellow arrows point at elytral interstriae 9, which in Figs 1 - 4 runs to the elytral sutures and blocks interstriae 1 - 8 from reaching elytral apex; in X. scolytoides (Fig. 5) all interstriae reach the posterior margin of the elytra.

Figures 16 - 24. Dorsal, lateral and front view of holotype of X. opacus (16, 19, 22); paratype of X. punctipennis (17, 20, 23); X. biseriatus (18, 21, 24).