Simulium (Hemicnetha) tarsale Williston

Hernández, L. M. & Shelley, A. J., 2005, New specific synonymies and taxonomic notes on Neotropical blackflies (Diptera: Simuliidae), Zootaxa 853, pp. 1-46 : 5-6

Simulium (Hemicnetha) tarsale Williston

(Figs. 3–6, 37, 38, 51, 52, 65, 66, 79, 80)

Simulium tarsale Williston, 1896: 268 –269. LECTOTYPE Ψ, West Indies, SAINT VINCENT; March [Without date or year.], (H.H.Smith) (BMNH, BM 1907–66) [Examined.] [Lectotype designation by Smart, 1942: 49.]

Simulium clavipes Malloch, 1914: 40 –41. HOLOTYPE Ψ, GUADELOUPE; 30.vii. [Without year.], (USNM) [Synonymy by Smart, 1942: 49.]

Simulium tarsale was described by Williston (1896) based on three specimens collected from the West Indies ( St. Vincent) by H. H. Smith and deposited in the BMNH. Smart (1940) in a paper dealing with the Simuliidae of British Guiana and the Lesser Antilles referred to the name of S. tarsale and mentioned that “no trace of the types of this species can be found in the British Museum”. Two years later he stated that the three specimens of the type series of S. tarsale were discovered in this museum, and he designated a lectotype ( Smart, 1942). In the same paper, he also discussed additional morphological characters that were not included in Williston’s (1896) original description of S. tarsale , examined type material of S. clavipes described by Malloch in 1914 from Guadeloupe, and concluded that both species were synonymous. This synonymy was confirmed by Stone (1969) while describing the simuliid fauna of Dominica. Stone also suggested that S. tarsale resembled species of the subgenus Hemicnetha , but refrained to include it in this subgenus because the fore tarsal segments II and III are flattened and the claws lack teeth. Both Coscarón (1987) and Crosskey & Howard (1997, 2004) were unable to place this species to subgenus.

We have examined the pinned female lectotype and paralectotype, the other paralectotype being missing. The thorax and left fore leg of the female lectotype remain pinned, while the abdomen, genitalia, other five legs, and one wing have been dissected and mounted on a slide; the head is missing. In the paralectotype the thorax, one wing, and three right legs remain pinned, and the head, abdomen, genitalia, one hind leg, and one wing are mounted on a slide. The two specimens are conspecific. We have compared the female thoracic pattern of the lectotype of S. tarsale with many paratype females of S. clavipes (Figs. 3–6), as well as the structure of the cibarium (Figs. 37, 38), wing setation, leg coloration, and morphology of the genitalia (Figs. 51, 52, 65, 66, 79, 80) and agree with Smart’s (1942) synonymy. We have also examined all material studied by Stone (1969) and confirm his identification of S. tarsale for the specimens collected in Dominica.

The female of S. tarsale externally resembles S. tarsatum (formerly S. mexicanum ) in having a dark brown to black thorax covered with yellowish hairs, but the former may be distinguished by the presence of 1+1 submedian black or silver pruinose areas [depending on light source] not present in S. tarsatum (Figs. 3, 4, 7, 8). Also, the genital fork of S. tarsale lacks the distinct triangular posterior processes (Fig. 79) that are present in S. tarsatum (Fig. 81; see Shelley et al., 2002: 220, Fig. 138, as S. mexicanum ). All characters of S. tarsale fall within the morphological variation found in species of the subgenus Hemicnetha and, consequently, we are here assigning this species to the tarsatum ­species group [formerly known as the mexicanum ­species group in Adler et al. (2004) & Crosskey & Howard (1997, 2004)].