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1 December 2011 On African Eupsilobiinae (Coleoptera: Endomychidae) with Descriptions of a New Genus and Species
Wioletta Tomaszewska
Author Affiliations +
Abstract

Species of the South African genus Microxenus Wollaston are revised. Microxenus laticollis Wollaston is redescribed, and M. muelleri sp. nov. and M. krugeri sp. nov. are described. Natalinus gen. nov. and its single included species, N. klimaszewskii sp. nov. are described. All of these taxa are diagnosed and illustrated, and a key to the species of Microxenus is presented. Female genitalia of newly described species are discussed in terms of monophyly of Eupsilobiinae. Zoogeographical and biological data of African Eupsilobiinae are summarized.

Introduction

Casey established the tribe Eupsilobiini in 1895 for his new species Eupsilobius politus. Historically it has been difficult to place among the Cerylonid Series families. Sen Gupta and Crowson (1973) classified Eupsilobiini in Cerylonidae, and synonymized Eupsilobius with Eidoreus, established in Erotylidae by Sharp (1885) for E. minutus Sharp from Hawaii. Crowson (1981) suggested the relationship of Eidoreus with Coccinellidae, but Sasaji (1986, 1987) placed it in Endomychidae and established Eidoreinae as a new subfamily, being unaware that the name Eupsilobiini of Casey was available. Pakaluk and Ślipiński (1990) followed Sasaji in the family placement and reviewed the subfamily Eupsilobiinae at the genus and species level.

Phylogenetic studies of the family Endomychidae based on adult and adult and larval morphology combined (Tomaszewska 2000, 2005) confirmed Eupsilobiinae as members of Endomychidae. Based on these studies, Eupsilobiinae forms a distinct, monophyletic group based on adult synapomorphies like median lobe coiled apically and ovipositor with stiff, inflated, infundibulum-like structure between the bursa copulatrix and the sperm duct. However, they are also characterized by having antennal grooves on the head and a median lobe with a T-shaped basal capsule (similar to that in Coccinellidae). The single known larva of Eupsilobiinae (Evolocera Sharp 1902) has a rigid tooth-like prostheca like in Mycetaea Stephens 1829 (Mycetaeinae). These phylogenetic analyses have not demonstrated any clear relationships between Eupsilobiinae and any other subfamily of Endomychidae.

Shockley et al. (2009b) listed 6 genera and 13 species of the subfamily. Five genera are restricted to small endemic areas of Central and South America (4 genera) and South Africa (1 genus), while Eidoreus is known from widely scattered islands like Cuba, Guadeloupe, Virgin Islands, Galapagos, Mascarene Islands, Seychelles, Sri Lanka, Fiji, French Polynesia, Solomon Islands, and Hawaii; E. politus (Casey 1895) was also collected in the Florida Keys.

So far, only the genus Microxenus was known from the Afrotropical region, established by Wollaston (1861) for M. laticollis from South Africa and placed in the family Mycetophagidae. Csiki (1905, 1910) placed this genus in the endomychid subfamily Mycetaeinae, and Strohecker (1953) followed this arrangement in his world catalogue of Endomychidae. Subsequently, Pakaluk and Ślipiński (1990) placed Microxenus in the subfamily Eupsilobiinae, and this placement was later confirmed by phylogenetic analyses (Tomaszewska 2000, 2005).

While studying additional material of Endomychidae from South Africa, two new species of the genus Microxenus and a new genus of Eupsilobiinae were discovered. These taxa are described here as follows: M. muelleri sp. nov., M. krugeri sp. nov., and Natalinus gen. nov. with its single new species N. klimaszewskii sp. nov. This work raises the number of known eupsilobiine species from the Afrotropical region to 4 and the known genera to 2.

Materials and Methods

Acronyms for depositories of specimens are:

  • NHM — The Natural History Museum, London, England

  • MIZ — Museum and Institute of Zoology PAS, Warszawa, Poland

  • TMNH — Transvaal Museum of Natural History, Pretoria, South Africa

Measurements were made using an ocular micrometer attached to an Olympus SZH-10 ( www.olympus.com) dissecting microscope. Measurements recorded were as follows: total length from apical margin of clypeus to apex of elytra; pronotal length from the middle of anterior margin to base of pronotum; pronotal width at the widest part; elytral length along suture, including scutellum; and elytral width across both elytra at the widest part. Male and female genitalia were dissected, cleared in 10% solution of KOH, and placed in glycerine on slides for further study. Illustrations were made from slide preparations using a camera lucida attached to the same Olympus dissecting microscope.

Scanning electron micrographs photographs were made using a Hitachi S-3400N ( www.hitachi.com), and digital photographs were made using a Leica digital camera (us.leica-camera. com) mounted on microscope and subsequently enhanced using Auto Montage software in the Electron Microscopy Laboratory of the MIZ.

Terminology used in this paper follows Tomaszewska (2010).

Results

Genus and species descriptions

Genus Microxenus Wollaston (1861)

  • Microxenus Wollaston 1861: 139. Type species, by monotypy: Microxenus laticollis Wollaston 1861. Pakaluk and Ślipinski 1990: 720–721 (redescription); Tomaszewska (2000) pp. 463–464 (redescription).

  • Diagnosis

    Microxenus is closely related to Natalinus. It differs from Natalinus by having the metaventrite with postcoxal lines, the mesoand metaventrite without postcoxal pits and the scutellum distinctly much more transverse, with at least weakly emarginate hind margin. The scutellum, which is at least 3 times wider than it is long, with weakly emarginate hind margin, is unique for Microxenus within Eupsilobiinae.

  • Description

    Length 1.20–1.45 mm. Body (Figures 1–3, 5–7, 14, 20, 26) is long-oval, gradually narrowing from about half of the body length to elytral apex; moderately convex; brown, shiny, smooth, covered with sparse and short pubescence (Figures 1–3).

    Head transverse and rather coarsely punctate. Gular sutures short, convergent anteriorly, widely separated. Eyes moderately large, weakly oval, prominent, coarsely-faceted. Antennal groove weakly impressed, short, expanding to posterior edge of eye (Figure 13); antennal sockets visible from above (Figures 19, 22, 30). Antenna (Figures 8–10, 12) reaches to about half the length of prothorax, 10-segmented with two-segmented club; club segments with elongate, membranous sensilla (Figures 9, 10, 12). Fronto-clypeal suture weakly arcuate. Mandible with arcuately curved outer edge; bifid at apex (Figure 13), with one small tooth on incisor edge; mola moderately large, transversely ridged; prostheca fringed; submola very small, membranous. Maxilla (Figure 13) with palpomeres 1 and 3 very short; terminal palpomere longer than remaining palpomeres combined, tapering apically. Galea blunt, with long, apical setae; twice as wide as lacinia. Lacinia with a few apical spines and setae on inner edge. Labium (Figure 13) with terminal palpomere stout and oval. Mentum trapezoidal with raised area medially. Tentorium with anterior arms fused medially and widely divergent anteriorly; corpotentorium curved (see Tomaszewska 2000: 501).

    Pronotum (Figures 19, 22, 30) transverse; pronotal surface finely and sparsely punctate; lateral margin narrowly bordered; basal sul