Lamproclasiopa laevior (Cresson)

Costa, Daniel N. R., Mathis, Wayne N. & Marinoni, Luciane, 2016, A revision of the shore-fly genus Lamproclasiopa Hendel (Diptera, Ephydridae), ZooKeys 631, pp. 1-99 : 12-15

Taxon classification Animalia Diptera Ephydridae

Lamproclasiopa laevior (Cresson) Figs 1-2, 3-6, 7

Ditrichophora laevior Cresson 1934: 200 [India. Darjeeling, Behar; HT ♂, ANSP (6509)].

Discocerina (Lamproclasiopa) laevior . Cresson 1945: 59 [generic combination]. Mathis and Zatwarnicki 1995: 168 [world catalog].

Lamproclasiopa laevior . Zatwarnicki and Mathis 2001: 39 [generic combination].

Diagnosis.

This species is distinguished from other congeners by the following combination of characters: Small to moderately small shore-flies, body length 1.85-2.65 mm, generally black, subshiny to shiny species. Head: Frons black, very sparsely microtomentose, anterior half shiny, posterior subshiny, transition from shiny to subshiny gradual. Antenna black, densely microtomentose, appearing velvety black. Face black, sparsely microtomentose, antennal grooves and lateral areas shiny, otherwise subshiny, lacking prominent, vertical stripes; face bearing 2-3 larger facial setae, dorsal seta at about midfacial height, dorsomesoclinate; ventral seta just dorsad of epistomal margin, slightly dorsoclinate; parafacial blackish yellow; gena moderately high, gena-to-eye ratio 0.16-0.22. Thorax: Mesonotum uniformly sparsely microtomentose, black, subshiny; presutural supra-alar seta well developed; pleural area concolorous with mesonotum, subshiny black. Wing hyaline to very faintly infuscate, lacking pattern of spots; vein R4+5 extended at gradual to costa, not angulate subapically or bearing a stump vein; costal vein ratio 0.47-0.55; M vein ratio 0.60-0.62. Femora and tibiae black; Forefemur with posteroventral setae slender, not stout and peg-like; foretarsus with basal 2 tarsomeres white, tarsomere 3 darkened, apical 2 black; mid- and hindtarsus with basal 2 tarsomeres yellow, apical 3 tarsomeres blackish. Abdomen: Generally black, mostly subshiny to shiny, dorsum of tergites very sparsely and finely microtomentose. Male terminalia (Figs 3-6): Epandrium in posterior view (Fig. 3) generally vertically oval, each lateral arm narrow, almost parallel sided, acutely pointed ventrally, in lateral view (Fig. 4) with dorsal 2/3 rectangular, basal 1/3 almost twice width as dorsal portion, widest subventrally, apex broadly rounded, posteroventral portion bearing several larger setulae; cerci in posterior view (Fig. 3) elongate, narrowly semicircular, medial margin nearly straight, gradually tapered toward ventral apex, this apex acutely pointed, dorsal apex with medial short, digitiform extension, in lateral view (Fig. 4) semicircular; gonite in lateral view (Fig. 6) narrowly elongate, somewhat rod-like, ventral 1/3 narrower than dorsal 2/3, in ventral view (Fig. 5) very robustly C-shaped with medial concavity, wider than high; aedeagus in lateral view (Fig. 6) tubular, gradually tapered to apex, apex generally broadly rounded with very apex narrowed, curved anteriorly at nearly right angle; phallapodeme in lateral view (Fig. 6) very narrow, L-shaped, apex toward base of aedeagus acutely pointed, apex toward hypandrium slightly flared and truncate, in ventral view (Fig. 5) as an elongate hourglass, expanded at each apex and truncate; hypandrium in lateral view (Fig. 6) narrowed posteriorly, then abruptly expanded to widest point subanteriorly, anterior margin abruptly narrowed, digitiform, in ventral view (Fig. 5) generally U-shaped, lateral arms widest at midlength, anterior margin broadly rounded, deep, posterior emargination narrowed on anterior 1/3, thereafter posterior more than twice anterior width.

Type material.

The holotype male of Ditrichophora laevior Cresson is labeled "Darjeeling Fruhstorfer/9233/TYPE Ditrichophora LAEVIOR E. T. Cresson, Jr. [maroon-red; " Ditrichophora LAEVIOR" handwritten]." The holotype is double mounted (minuten pin in a rectangular block of foam), is in good condition (abdomen removed, dissected, and in an attached microvial), and is deposited in the ANSP (6509). A female paratype (ANSP) bears the same locality label as the holotype.

Type locality.

India. West Bengal: Darjeeling, Cooch Behar (26°24.7'N, 89°23.1'E). The holotype was apparently collected in the foothills of the Himalayas in the state of West Bengal between Darjeeling and Cooch Behar.

Other specimens examined.

INDIA. Meghalaya: Shillong (Botanical Gardens; 25°34.6'N, 91°53.2'E), 20 Apr 1980, A Freidberg (9♂, 2♀; USNM).

SRI LANKA. Central Province: Horton Plains (6°48.7'N, 80°47.3'E), 23 Apr 1980, W. Mathis, T. Wijesinhe & L. Jayawickrema (9♂, 4♀; USNM).

Distribution

(Fig. 7). Oriental: India (Meghalaya, West Bengal), Sri Lanka.

Remarks.

Although similar and perhaps related to Lamproclasiopa ecuadoriensis , this species is distinguished from congeners by the white forebasitarsomere, which is contrasted with the black, apical tarsomeres; the short gena (gena-to-eye ratio 0.10-0.14); and the shape of structures of the male terminalia (Figs 3-6).

The distribution of this species is anomalously disjunct. Except for this species, which is found on the Indian Subcontinent, all other congeners occur in the New World, especially in tropical zones, which are many thousands of kilometers from India and Sri Lanka. This distributional anomaly prompts a number of questions. For example, is this species indeed a valid congener? If so, what is it related to? How did it come to be found on the Indian Subcontinent when other congeners occur in the New World? Although our responses to these and other questions are not wholly satisfactory, often being based on tenuous evidence, we offer some thoughts and observations.

Based on morphological evidence, both external and from structures of the male terminalia, we affirm that this is a congener within the genus Lamproclasiopa . Within Lamproclasiopa , we suggest that this species, being generally characterized by homoplasious characters, would probably be near the base of the evolutionary stem or node giving rise to all other included congeners. See also our remarks under the species group.

As we noted in the introduction, however, characterization of Lamproclasiopa has only become reasonably well resolved in recent decades, resulting in earlier recognized species, including this species, being first described in another genus. Cresson (1934) first described this species in Ditrichophora then transferred it to the subgenus Lamproclasiopa within Discocerina ( Cresson 1945). Over 50 years later, Zatwarnicki and Mathis (2001) accorded generic status to Lamproclasiopa and included this species along with other congeners in this genus.