Acylophorus trigonocephalus Cameron

Lott, Derek A., 2010, The species of Acylophorus Nordmann (Coleoptera: Staphylinidae: Staphylininae) in continental sub-Saharan Africa, Zootaxa 2402, pp. 1-51 : 29-30

Acylophorus trigonocephalus Cameron

(Figs 21, 70, 97, 135)

Acylophorus trigonocephalus Cameron, 1949: 322 ; Herman, 2001: 3037.

Acylophorus leonensis Bordoni, 1994: 312 ; Herman, 2001: 3033 (new synonym).

Redescription. Length 6.5mm. Body black with iridescent abdomen, pronotum sometimes slightly paler. I have also seen one specimen that is completely pale brown. Antennae brown to dark brown, first segment often paler. Legs pale, sometimes with darkened femora and tibiae. Palpi all pale.

Head small in comparison with pronotum (pronotum 1.9x wider than head) more or less as long as wide with well developed temples behind large eyes (Fig. 21). Head pigmented in front of antennal insertion. Micro-punctures very sparse and scarcely detectable at 40x magnification. Short pubescence behind eyes. Three pairs of interocular setae and a line of five postocular setae just visible from above on each side. Maxillary palpi with last two segments pubescent, terminal segment elongate, rounded on both sides, but slightly asymmetric, longer than penultimate segment which is also elongate ( Fig. 70 ). First segment of antenna longer than next five. Segments I to IV elongate, IX to X transverse ( Fig. 97 ).

Pronotum transverse (1.3x wider than long) with rounded sides, widest in basal half. Shining with no micro-punctures. Marginal setae very long and more numerous than in A. orientalis . One pair of dorsal and one pair of lateral setae. Elytra transverse (1.65x wider than long) with long but sparse pubescence and coarse asperate punctures which are stronger than in A. orientalis . Apical bristles much longer than hairs on the rest of the elytra. Abdominal tergites also with long, sparse pubescence. Punctures much sparser on apical half of each tergite than on basal half. Apical fringe of bristles on each tergite of two distinct lengths, the shorter bristles more numerous than the longer bristles.

Male sternite IX with apex simple. Aedeagus with bilobed paramere, each lobe narrow, parallel, pegs confusedly arranged toward apex, which has numerous short marginal hairs ( Fig. 135 ). Median lobe with apex barely expanded, only just surpassing paramere.

Type material. Cameron described A. trigonocephalus from material collected in Côte d’Ivoire. One syntype has been located and is here designated as the lectotype in order to fix the identity of the species. Lectotype Ƥ: “IFAN-1946 TONKUI C.I. 900–1200m A. VILLIERS / FORET PRIM; 20-30-IX / M. Cameron Bequest B.M. 1955-147 / Dr. M. Cameron det., 1948; Acylophorus trigonocephalus Cam. COTYPE / LECTOTYPE Acylophorus trigonocephalus Cameron Ƥ det. DA Lott” ( BMNH).

Acylophorus leonensis Bordoni. Holotype 3: “S. Leone W. Area Sugar Loaf Mt. Rossi 7.3.92 / HOLOTYPUS / HOLOTYPUS Acylophorus leonensis sp. n. Bordoni det. 1992” (cBord). In the original description Bordoni compared his new species to A. rossii , but not to A. trigonocephalus with which it is similar in all respects. Consequently, A. leonensis is here synonymised with A. trigonocephalus .

Further material examined. R.D. CONGO: Kivu: Kabari, SE Kahuzi, 2080/ 2200m, N Leleup, viii.1951, 1 Ƥ ( ISRNB); Mwenga, Luiko, 2050m, N Leleup, 21. i.1952, 1 Ƥ ( IRSNB). SIERRA LEONE: Northern Province: Sinikoro, W Rossi, 31. xii.1982, 13 (cBord). ZIMBABWE: Kutsaga near Harare Airport, W Rossi, 18. vi.1997, 13 (cLott).

Distribution and bionomics. Recorded from Sierra Leone, Côte d’Ivoire, Congo and Zimbabwe, always in small numbers ( Fig. 147 ). Recorded habitats include primary forest, montane forest and the margins of a fast-flowing stream.

Comparative notes. Easily distinguished from A. orientalis by the characters common to the species group, two pubescent terminal segments on the maxillary palpi, the three pairs of interocular punctures and the larger number of marginal setae. Within the group it can be recognised by a combination of the long setae on the head and pronotum, the large eyes and the moderately transverse elytra. The aedeagus is also distinctive.

Figures

FIGURE 147. Distribution of species in the Acylophorus trigonocephalus group = A. trigonocephalus Cameron, = A. setiger new species, = A. usambarae Bernhauer, = A. grandis Bernhauer; = A. bafutensis Levasseur).

FIGURES 51 – 76. Terminal segments of the maxilliary palpi of Acylophorus species. 51, A. orientalis Fauvel; 52, A. nitens new species; 53, A. rossii Bordoni, 54, A. bumbunae Bordoni; 55, A. capensis Cameron; 56, A. dankalensis Bordoni; 57, A. tshuapensis new species; 58, A. makhoreae new species; 59, A. densipennis Bernhauer; 60, A. antennalis Cameron; 61, A. collarti Cameron; 62. A. micans new species; 63, A. allardi Levasseur; 64, A. congoensis Cameron; 65, A. ziloensis Levasseur; 66, A. mareei Bernhauer; 67, A. salifi new species; 68, A. lomaensis Levasseur; 69. A. minor new species; 70, A. trigonocephalus Cameron; 71, A. setiger new species; 72, A. usambarae Bernhauer; 73, A. grandis Bernhauer; 74, A. bafutensis Levasseur; 75, A. kambuiensis Bordoni, 76. A. lualabaensis Levasseur.

FIGURES 97 – 103. Antennae of Acylophorus species. 97, A. trigonocephalus Cameron; 98, A. setiger new species; 99, A. usambarae Bernhauer; 100, A. grandis Bernhauer; 101, A. bafutensis Levasseur; 102, A. kambuiensis Bordoni, 103. A. lualabaensis Levasseur. FIGURES 104 – 107. Details of Acylophorus delphinus Fauvel. 104, forebody; 105, terminal segments of maxilliary palpi; 106, antenna; 107, aedeagus. FIGURE 108. Lateral view of head of Acylophorus salifi new species.

FIGURES 134 – 137. Aedeagi of species in the Acylophorus trigonocephalus group. 134, A. grandis Bernhauer; 135, A. trigonocephalus Cameron; 136, A. setiger new species; 137, A. bafutensis Levasseur (reproduced from Levasseur, 1968 and not drawn to scale). FIGURES 138 – 139. Aedeagi of species in the Acylophorus kambuiensis group. 138, A. kambuiensis Bordoni, 139. A. lualabaensis Levasseur.