Parapachycerina lalitra, 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 : 144-145

Parapachycerina lalitra sp. n.

Figs 3 , 19 , 25–27

Etymology: From Malagasy lalitra (a fly) ( Anonymous 1999).

Diagnosis:

Diminutive (ca 2.5 mm) Malagasy species with yellow-orange head and thorax, and dark brown abdomen. Ocellar triangle small and dark brown, with sides and base of triangle equal. Postpedicel all yellow with no dark patches or infuscation. Profemoral ctenidium with ca 4 setulae. Wings hyaline. P. talea (which can be sympatric, e.g. at Andasibe), is larger (ca 3.7 mm), darker orange in colour, and has fumose wings and darkened apices to postpedicels.An undescribed Parapachycerina taxon A, represented by a single male from the east coast is extremely similar, and can only be separated by dissection of the male genitalia (see below and Figs 25–28 ). Another undescribed Malagasy taxon (B) from Amber Mt in the far north of the island, is larger and lacks a profemoral ctenidium (see below).

Description:

Colour: Head yellow, ocellar spot dark brown and confined to ocellar triangle, scape, pedicel and postpedicel yellow (no darkening, not even at aristal base). Maxillary palpi yellow. Thorax yellow, medial orange-brown stripe on scutum (between dorsocentral bristles) and scutellum, stripe more pronounced on scutellum. Brown wedge on notopleuron (may be faint). Haltere pale yellow. Legs all yellow. Abdomen dark brown, first two segments slightly paler. Protandrium, epandrium and genitalia yellow.

Head: Largely as per genus. Orbital plates shining, but not easily differentiated from surrounding postfrons at low magnification (6–25×). Ocellar triangle small, all sides approximately equal in length, ca 4 ‘fugitive’ setulae between posterior ocelli; vertex/ occiput boundary rounded (not abrupt). Prefrons very weakly tumid, slightly translucent.

Thorax: Largely as per genus. Acrostichal bristles very short, only ca 0.2× length of posterad dorsocentral bristles.

Legs: Profemoral ctenidium with ca 4 setulae. Profemur posteriorly with ventral row of ca 2 setae and dorsal row of ca 4 setae.

Wings: Hyaline.

Male terminalia ( Figs 19 , 25–27 ): Protandrium saddle-shaped. Epandrium narrow dorsally and laterally, slight protuberance in posterior lateral margin; epandrium expands posteriorly in broadly rounded, hirsute epandrial process. Surstylus long thin lamella fused to inner edge of epandrium, dorsally with weakly hamate tip. Cerci dark brown, hirsute. Hypandrium rather complex relative to other species in genus, transversely broad but longitudinally narrow ‘transverse band’ (broader than ‘aedeagal tube’), fairly short lateral posterior arms that rise dorsally at oblique angle then curve back anteriorly and continue as ‘dorsal loop’ terminating on anterodorsal (not lateral) corner of aedeagus; below ‘transverse band’ is unique (within genus), lightly sclerotised extension or ‘apron’. Aedeagal apodeme stem long (exceeding aedeagus in length), posterior arms very short. Aedeagus composed of two halves (‘wings’) and membranous medial section; aedeagal halves of unusual shape, externally with noticeable mucro on ventrolateral margin, deep incision subapically and recurved, falcate apices (resembling claws); small spinules (teeth) on posterior subapical margin of aedeagal halves. Gonopods long, unexceptional, broadly tapering to rounded apices; unlike other species in genus, gonopods do not tightly ensheath aedeagus. Subepandrial sclerite rather lunate in shape and lying ventrad of cercus. Ejaculatory apodeme not evident (probably lost during dissection).

Measurements: ơ (n=1) ^(n = 1): total length – ^= 2.5, ơ = 2.5; head height – ^= 0.7, ơ = 0.5; head width – ^= 0.8, ơ = 0.8; head length – ^= 0.4, ơ = 0.4; thorax length – ^= 1.2, ơ = 1.1; wing length – ^= 1.4, ơ = 1.3; abdomen length – ^= 0.9, ơ = 1.1.

Holotype: ơ MADAGASCAR: Andasibe (= Périnet), xii.1955, B. Stuckenberg ( NMSA).

Other material examined: MADAGASCAR: 1^same datum as holotype ( NMSA); 2 ^Ranohira , 26.i– 4.ii.1958, B. Stuckenberg ( NMSA) .

Distribution: Restricted to Madagascar. Recorded from eastern escarpment (Andasibe), and western edge of Horombe escarpment in south-central portion of the island (Ranohira).

Figures

Figs 2, 3. (2) Dorsal view of head of Parapachycerina munroi Stuckenberg, (3) oblique lateral view of head of P. lalitra sp. n. Note small anterior fronto-orbital bristles (relative to posterior fronto-orbital bristles), short distance separating fronto-orbital bristles, plumose aristae and long ocellar bristles.

Figs 16–19. Lateral views of outer ơ terminalia: (16) P. munroi Stuckenberg, (17) P. bispina sp. n., (18) P. infuscata sp. n., (19) P. lalitra sp. n. (protandrium of P. lalitra not illustrated). Abbreviations: cer – cercus, epa – epandrium, pro – protandrium, sur – surstylus.

Figs 25–27. Inner ơ genitalia of P. lalitra sp. n.: (25, 26) dorsal and lateral views, (27) aedeagus ‘wing’.