Parapachycerina talea, Davies & Miller, 2008

Davies, Gregory B. P. & Miller, Raymond M., 2008, Revision of the Afrotropical species of Parapachycerina (Diptera: Lauxaniidae), African Invertebrates 49 (2), pp. 131-131 : 147-149

Parapachycerina talea sp. n.

Etymology: From Latin talea (small rod), referring to posterior extension of ocellar spot that reaches onto the occiput.

Diagnosis:

Robust Malagasy species only known from female specimens. Ocellar triangle small and compact. Ocellar spot brown (not black) with narrow extension (‘prong’) posteriad. Postpedicel with darkened apical end. Thick brownish edge to scutum/notopleuron. One sternopleural bristle. Profemoral ctenidium present. Anterior edge of wing fumose (specifically costal cell, marginal cell and anterior part of submarginal cell; no brownish smudges on anterior and posterior cross-veins). Undescribed taxon B closely resembles P. talea , see below for further details.

Description:

Colour: Mainly yellow-orange. Scape and pedicel yellow. Distal half of postpedicel and area at aristal tumidity brown, rest of postpedicel yellow. Ocellar spot brown with characteristic brown medial prong extending posteriorly. Maxillary palpi yellow.Thorax yellow with rather faint orange-brown medial stripe on mesonotum; edges of notopleuron infuscated orange-brown. Abdomen brownish orange.

Head: Orbital plates weakly differentiated. Basal half of scape recessed under anterior lip of postfrons. Vertex rounded. Ocellar triangle small, sides slightly longer than base.

Thorax: Chaetation largely as per genus. One sternopleural bristle.

Legs: Ctenidium present on profemur, ca 9 setulae. Profemora posteriorly with ventral row of ca 2 setae and dorsal row of ca 4 setae. Mesofemur with medioanterior row of 5 setae.

Wings: Costal cell, marginal cell and anterior section of submarginal lightly infuscated.

Abdomen: Male terminalia unknown.

Measurements: ^(n=3): total length – 3.8 (3.6–4.1); head length – 0.5; head height – 0.8; head width – 1.1; thorax length – 1.8 (1.7–1.9); abdomen length – 1.5 (1.3–1.7); wing length – 3.5 (3.3–3.8).

Holotype: ^MADAGASCAR: Andasibe (= Périnet), 5.xii.1957, F. Keiser ( MHNB).

Other material examined: MADAGASCAR: 1^Vohiparara , 13.ix.1958, F. Keiser ( MHNB); 1^Ambalamanakana, 18.i.1958, F. Keiser ( MHNB) .

Distribution: Restricted to Madagascar. Known only from forested areas along eastern versant.

Undescribed taxon A

A male from east coast of Madagascar (Ivondro, i.1900, C.Alluaud, MNHN) is extremely similar to P. lalitra externally, but differs in genitalic features in having shorter gonopods, a weaker hypandrial ‘apron’ and lacking the mucro on the ventrolateral margin of the aedeagus ( Figs 28–30 ). The single specimen available is in rather poor condition, and the genitalia were left too long in KOH during extractive treatment, resulting in the genitalic sclerites becoming largely translucent and difficult to view. Consequently, this taxon is left undescribed until further material becomes available.

Undescribed taxon B

A single female from the lush forest on Montagne d’Ambre, Antsiranana (Diego- Suarez; 23.xi–4.xii.1958, B. Stuckenberg, NMSA) appears to represent a new species. For want of more material, it is left undescribed. It resembles P. talea in being a robust, deep orange Parapachycerina with very lightly infuscated wings. It differs, however, in lacking the posterior extension from the ocellar spot, and in lacking a profemoral ctenidium (a feature which also separates it from the smaller P. lalitra ). Other salient features of this specimen are: small ocellar triangle (with sides approximately equal); blackish ocellar spot; postpedicel mostly yellow but darkened apically; sides of notopleuron strongly infuscated; dark orange medial stripe on mesonotum; and 2 sternopleural bristles. The isolated Amber Mt (a forest-clad late Tertiary volcano) is well-known as a site of local endemism in Madagascar.

Undescribed taxon C

The late Loïc Matile collected a distinctive female specimen from Grande Comore, the largest island in the Comoros archipelago (Grande Comore, La Grille (Guiri), 850– 900 m, 15.xi.1973, L. Matile, MNHN). Immediately notable about this specimen are the large black spot on the mesopleuron, the weakly fumose anterior part of the wings, three broad, black mesoscutal vittae, and the black marks on the lateral sides of the occiput. The profemoral ctenidium is present. The arrangement, size and orientation of cephalic setation are as per the genus .

This specimen definitely seems to represent a new species, but until further specimens are procured, in particular males, it is left undescribed. The presence of Parapachycerina on Grande Comore hints at the possibility that the genus may yet be found on the Seychelles. Based on superficial colouration similarity and the presence of a profemoral ctenidium, this taxon may be the sister-species of P. infuscata . Interestingly, the three species with profemoral ctenidia are the two Malagasy species and P. infuscata of the African mainland. Taxon C is a geographical annectant step joining these ctenidiabearing Parapachycerina taxa. Whether this is a coincidence, or represents cognate phylogenetic affinity, is still to be determined.

Figures

Figs 28–30. Inner ơ genitalia of undescribed taxon A, Ivondro, Madagascar: (28, 29) dorsal and lateral views, (30) aedeagus ‘wing’. Note that the ventral area of the hypandrial ‘apron’ is not illustrated due to the extreme transparency of the sclerite following over-treatment in KOH.