Dasyrhicnoessa ciliata

Munari, Lorenzo, 2015, Taxonomic and distributional notes on two species groups of the genus Dasyrhicnoessa Hendel (Diptera: Canacidae: Tethininae), Zootaxa 3920 (4), pp. 545-554 : 550-553

The Dasyrhicnoessa ciliata group

This species group is characterized mainly by the long-haired arista (fig. 15), which is an apomorphic character state with respect to the groundplan of the subfamily Tethininae , as well as by the greatly enlarged posterior surstylus of the male terminalia. These peculiar features, in addition to the yellow body and legs, and the characteristic slender habitus of these beach flies (fig. 16), are also found in D. longisetosa Munari, 2004 and D. priapus Munari, 2004 .

D. ciliata appears to be the sister species of the monophyletic clade D. longisetosa plus D. priapus , the latter two species additionally sharing a peculiar cluster of thin setulae arising from the mesial side of the posteromarginal surface of the posterior surstylus (figs. 19─22), as well as sharing the lack of a true ctenidium, which is well developed in D. ciliata .

The following three species are referred to the Dasyrhicnoessa ciliata group:

ciliata Munari, 2004 (figs. 17, 18)

Dasyrhicnoessa ciliata Munari, 2004: 34 [ Australia. Northern Territory: Buffalo Ck, Darwin]; the holotype ♂ is deposited in AMS (K186736), two paratypes ♀♀ (same data as holotype) are in AMS and in LMC, respectively.

Distribution. Australasian/Oceanian: Australia (Northern Territory).

Remarks. This species is hitherto known only from the type locality, but it is possibly more widely distributed on the coasts of the Northern Territory of Australia and of the neighbouring Gulf of Carpentaria, as well as, albeit to a lesser extent, on some islands of the Timor and Arafura Seas (see the remarks under D. longisetosa ). Apart from the characters given in the key, D. ciliata is distinguished from congeners mainly by the roughly subquadrate posterior surstylus (in lateral view) (fig. 17), bearing a sharply angled anterior lobe, and by having numerous stout, obtuse, tubercle-like setae on the distal one-third of the mesial surface (figs. 17, 18). The posterior surstylus is strongly setulose, but with no obvious cluster of thin setulae arising from the postero-marginal surface.

longisetosa Munari, 2004 (figs. 15, 16, 19, 20, 23)

Dasyrhicnoessa longisetosa Munari, 2004: 38 [ Papua New Guinea. Port Moresby, mangroves]; the holotype ♂ is deposited in AMS (K186738), fifteen paratypes (4 ♂♂11 ♀♀) are from “ Australia, Queensland, Gladstone, mangroves; ibidem, Mackay, mangroves”. The paratypes are deposited in AMS and in LMC. Distribution. Australasian/Oceanian: Australia (Queensland), Papua New Guinea.

Remarks. Similar to the preceding species, the distribution of D. longisetosa also extends from Papua New Guinea (southern coast), through the Torres Strait (approximately 150 km (93 mi) wide at its narrowest extent), to Queensland (central eastern coast). Thus, the distribution of D. longisetosa would suggest a biogeographical continuum between the Papuan Province and the northeastern territories of Australia, which probably occurred either via passive transfer (anthropic, avian, wind transfers) or during the Pleistocene, when land connections joined those vast territories together ( Udvardy, 1975). This species is distinguished from congeners mainly by the mesonotal setae being perceptibly longer than those of any other congener (fig. 23). Furthermore, in D. longisetosa the male terminalia are characterized mainly by the large, almond-shaped (in lateral view), posterior surstylus (fig. 19), which appears tapered and acutely pointed in posterior view (fig. 20). The posterior surstylus bears a characteristic cluster of fine setulae arising from the mesial surface, as well as 3-4 robust, stout, tubercle-like setae on the posterior border (figs. 19, 20).

priapus Munari, 2004 (figs. 21, 22)

Dasyrhicnoessa priapus Munari, 2004: 44 [ Australia. Queensland: Eurimbula, mangroves]; the holotype ♂ is deposited in AMS (K186742) along with a paratype ♀ (same data as holotype).

Distribution. Australasian/Oceanian: Australia (Queensland).

Remarks. This species as well can be reliably identified mainly by examination of the male terminalia (figs. 21, 22). Indeed, it is markedly distinguished from congeners mainly by the following combination of genitalic characters: epandrium with robust, short setation, except for a very long, strong seta placed dorsolaterally; posterior surstylus strikingly large, exhibiting an irregular, strongly sinuous posterior margin (in lateral view); posterior surstylus, in both lateral and posterior views, with an obvious posterior lobe bearing a cluster of fine setulae arising mesially; numerous robust, stout, tubercle-like setae on the mesial surface of posterior margin, and 2-3 of these setae more widely spaced on antero-apical margin; cercus unusually large, bearing long setae oriented mesially.