Sabeurina, Deeming, 2018

Deeming, John C., 2018, A revision of the Afrotropical species of Pachylophus Loew (Diptera: Chloropidae) and some related Ovoviviparous genera, Zootaxa 4482 (1), pp. 1-51 : 27-29

Sabeurina gen. n.

Type species Eurina minuta Loew, 1860 by present designation.

The Afrotropical species, minuta Loew , described in the genus Eurina Meigen, 1830 , which is known from S. Africa, Lesotho and Kenya, was excluded from Eurina by Sabrosky and was cited by him as an unplaced species (1980: 712). M. von Tschirnhaus (Bielefeld) possesses a female from Tanzania, 4°03'S 37°56'E, Southern Pare- Mountains, Kwainka, leg. I. Brake, 10–17.vii.1996 (X1233), from which some notes are added here in squared brackets.

Diagnosis. Female with only a single ovariole functional at any given time and with cerci broad and flat [female cerci not laterally compressed, two times longer than broad]; male with mesolobus lacking setulae and surstylus short, blunt, fused to epandrium; eye with scattered very short setulae; frontal triangle extending to or almost to full length of frons, lacking any row of marginal setae situated within it [on each side 15 interfrontals in a row directly on the edge of the triangle]; frons strongly projecting in front of eyes, forming an acute frontofacial angle with the strongly retreating face; both medial and lateral vertical setae well developed; ocellars small and proclinate; [postocellars convergent and proclinate]; vibrissa minute; [proboscis with normal labellum, each lobe with three pseudotracheae, the central pair without piercing structures]; antenna with postpedicel longer than deep, [as long as the long pedicel], apically rounded and with the filiform and minutely pubescent arista situated closer to its base than apex; of dorsocentral setae only the prescutellar developed; [outer postalar normal, inner postalar small, supraalar absent], costa extending to apex of R4+5, which is not bent forward on apical section; R2+3 long, in close proximity to R1 and costa throughout its length; R4+5 straight; apical section of M1 very weakly developed; [wing tip in mid between R4+5 and M1]; crossveins separated by quite twice length of posterior crossvein; hind femur neither enlarged nor more robust than the fore femur; hind tibia shining on dorsal surface, lacking a "sensory organ"; [mid tibia with a thin black spur at apex, that as long as diameter of tibia at apex].

Etymology. The new genus name is compounded to include the first syllable of Sabrosky in honour of Dr. Curtis W. Sabrosky, who spent a lifetime advancing our knowledge of Diptera and who died unexpectedly in 1997.

Affinities. The combination of a slender hind femur, R2+3 running close to the costa throughout its length, lack of a "sensory area" on the hind tibia, frontal triangle bare, a row of setulae present only on the extreme margin, in the male, the mesolobus without setulae and the surstyli fused to the epandrium places Phyladelphus as the closest described relative of Sabeurina . The male terminalia of the two genera are very similar indeed (compare plate 7, Fig. 29 of Sabeurina occidentalis with that of Phyladelphus geminus (Deeming 1981: 825, Fig. 75)). Certainly, the described species of Phyladelphus (inclusive of those described here) have the arista either thickened by compact short hairs or lanceolate, whereas Sabeurina does not. This difference, however, I do not consider as being diagnostic at the generic level on account of the haphazardness of such aristal modification elsewhere ( Andersson 1979). The head shape of the two genera differs greatly, the head of Phyladelphus being deeper than long and with the frons only slightly projecting in front of the eye, whereas in Sabeurina the head is much longer than deep and with the frons strongly projecting. Furthermore, the frontal triangle of Phyladelphus has its lateral margins sinuate in all species, convex posteriorly and concave anteriorly, so that its anterior part is drawn out into a narrow point. In Sabeurina the lateral margins are either perfectly straight ( S. minuta ) or it is anteriorly broadly rounded ( S. occidentalis ). The first instar larva of Sabeurina lacks the specialised thoracic spicules described here for Phyladelphus .

Andersson (1977), in his assessment of the “ Eurina ” species group illustrated the male terminalia of Eurina calva Egger, 1862 , for want of material of other species. However, this was not the type species of the genus and given the possibility of alternative generic combinations of some species in this group I considered it necessary to illustrate the male terminalia of Eurina lurida Meigen, 1830 (Fig. 30) for comparison with Sabeurina and closely related genera. Furthermore, in his figure he omitted the distal part of the hypandrium.

Sabeurina differs from Eurina in having the abdominal sternites very narrow in both sexes and the hypandrium with the medial of the two distal processes only about 1/5 as long as the basal part of the deep U-shaped hypandrium. In Eurina the medial process is about 1½ times as long as the basal part of the much shorter U-shaped hypandrium. In Eurina the mesolobus is very short, hardly extending into the sub-epandrial space, whereas in Sabeurina this structure is well developed and extends to more than half way across the sub-epandrial space.

Dudeurina Ismay, 1995 , known only from the holotype from Java, is similar to Sabeurina in having the cephalic setae relatively well developed, whereas in Eurina the medial and lateral vertical setae and the ocellar and orbital setae cannot be distinguished from the similarly minute other cephalic setulae. It differs from Sabeurina by having scattered setulae on the frontal triangle, which is very broad and almost parallel-sided. The hypandrium is also much shorter with the medial process about half the length of the basal part.

Paraeurina Duda, 1933 is also known only from the holotype taken in Lago di Monfalcone, Italy. Duda described the frons as more truncate than in Eurina , lustrous with a straight margin and a broad and shallow but distinct furrow. The type is badly damaged and only the thorax and one wing remain (J.W. Ismay pers. comm.)

Sineurina Yang & Yang, 1992 (erected as a replacement name for Pseudeurina Yang & Yang, 1990 , nec de Meijere, 1904, to accommodate their new species Pseudeurina guizhouensis ) has a short mesolobus, a broad frontal triangle (right up to anterior margin of frons) with convext margins and a hypandrium with a very short medial process (about 1/10 the length of the basal part. The cephalic setulae are very short, unlike those in Sabeurina and Dudeurina .

Trichieurina Duda, 1933 is distinguished by its long and dense cephalic setulae and a deep lustrous median furrow on the frontal triangle, which has numerous long scattered setulae on the non-lustrous parts of its surface. The anepisternum and anepimeron are bare as in Sabeurina but both sclerites are setulose in Eurina .