Thinophilus spinatus Samoh, Satasook & Grootaert, 2017

Grootaert, Patrick, 2018, Revision of the genus Thinophilus Wahlberg (Diptera: Dolichopodidae) from Singapore and adjacent regions: A long term study with a prudent reconciliation of a genetic to a classic morphological approach, Raffles Bulletin of Zoology 66, pp. 413-473 : 460-461

Thinophilus spinatus Samoh, Satasook & Grootaert, 2017

(Fig. 50)

Thinophilus spinatus Samoh, Satasook & Grootaert, 2017: 25 (Figs. 25–30).

Material examined. SINGAPORE: 1 female, Sarimbun (SR3), mangrove, 21 May 2014 (leg. J. Puniamoorthy, Lee Kong Chian Natural History Museum, Singapore) .

Diagnosis. A medium-sized (4.3 mm), slender-legged species with yellow legs, but fore coxa black except for apical third. The femora are spindle-shaped and the fore femur in male as well as in female bear long, brown spine-like ventral bristles.

RAFFLES BULLETIN OF ZOOLOGY 2018

Fig. 50. Thinophilus spinatus Samoh, Satasook & Grootaert, 2017 male habitus (Photo: A. Samoh).

Etymology. The specific epithet refers to the ventral bristles on the fore femur that are present in both male and female.

Remarks. There are two slender-legged species in Southeast Asia with brown spine-like bristles on the fore leg: Thinophilus spinatus Samoh et al., 2017 and T. spinatoides Samoh et al., 2017 . How to distinguish them can be found in the key and in the following comments.

Thinophilus spinatoides is particular in that the basal quarter of the fore femur is much spindle-shaped dilated. It is less dilated in T. spinatus . The fore tibia is much longer than the fore femur; it is shorter in T. spinatus . The fore tibia is slender and without anterodorsal bristles in the male, but present in the female; the fore tibia is stouter and with 2 long anterodorsals in T. spinatus . The fore tarsomere 3 is contrastingly yellowish white, while tarsomeres 4 and 5 are broadened and black. In T. spinatus the fore tarsomere 3 has the same pale yellowish colour as tarsomeres 1 and 2 and tarsomeres 4 and 5 are black but not broadened. Only the base of the fore coxa is brown in T. spinatoides while the basal 2/3 of the fore coxa is brown in T. spinatus . The lower postocular bristles are yellow in T. spinatoides while black in T. spinatus . In T. spinatoides the anal vein is distinct in the basal 2/3 while not distinct at all in T. spinatus .

Distribution. Southern Thailand (Andaman Sea), Singapore.