Neoephydra Mathis

Mathis, Wayne N. & Marinoni, Luciane, 2016, Revision of Ephydrini Zetterstedt (Diptera: Ephydridae) from the Americas south of the United States, Zootaxa 4116 (1), pp. 1-110 : 32-33

Genus Neoephydra Mathis

Dimecoenia in part of authors [misidentification], not Cresson 1916: 152.— Wirth 1968: 23 [catalog of South American species, distribution].—Lizarralde de Grosso 1989: 57 –58 [fauna of Argentina].— Mathis and Zatwarnicki 1995: 238 –240 [world catalog].

Neoephydra Mathis 2008: 9 [type species: Neoephydra araucaria Mathis 2008 , original designation].

Diagnosis. Neoephydra is distinguished from other genera of Ephydrini by the following characters: medium-sized to large shore flies, body length 3.00– 5.30 mm.

Head: Mesofrons with vestiture variable; lacking cruciate, interfrontal setae; lateroclinate, fronto-orbital setae either 2 or 5–6, not 3; basal flagellomere lacking large seta inserted on lateral surface; arista moderately short, thickened basally, with macropubescent vestiture dorsally, apical half style-like, bare; postocular setae variable; large facial setae declinate; gena moderately high to high, gena-to-eye ratio 0.30 or larger.

Thorax: Acrostichal setae no well-developed; dorsocentral setae 5 (1+4), development variable; supra-alar seta variable; presutural supra-alar seta lacking; intrapostalar seta present, although sometimes weak; hindtibia lacking apical seta.

Abdomen: Male terminalia symmetrical, epandrium longer than wide; surstyli fused medially except near apices and with 1–2 lateral projecting processes or prongs in addition to apical prominences; aedeagus shallowly crescent-shaped and generally quite slender, at least apically; female ventral receptacle with small papilla-like operculum.

Distribution. Members of Neoephydra are known only from the Neotropics, where they are widespread and occur in habitats similar to those of the Holarctic genera Ephydra Fallén and Setacera Cresson.

Natural history. Like many taxa of the subfamily Ephydrinae , specimens of Neoephydra inhabit diverse and what would appear to be environments inimical to life. Oliveira (1954a) noted that Dr. Herman Lent found larvae, pupae, and adults of a Chilean species in the hot effluent of a high altitude, hot water geyser located at El Tatio (5200 m), near San Pedro de Atacama. Although the temperature of the water was not taken, Dr. Lent stated that it was sufficiently hot to cook an egg. Dr. Lent also observed a small, predatory toad, Telmatobius peruvianus Wiegmann ( Anura : Leptodactylidae ), whose diet consisted solely of freshly emerged, adult flies.

Numerous larvae and pupae of a second species, collected in southern Brazil, were found to inhabit warm, algae-covered, and often saline water that had accumulated in depressions of large rocks near the sea shore ( Oliveira 1954b, 1958). Water evaporation from the shallow depressions is rapid, accounting for the concentration of salts.

Hennig (1943) and Oliveira (1954b, 1958) described and figured the larvae of four species belonging to this genus. Based on these Figs., larvae of Neoephydra are typical of the tribe, with eight pairs of claw-bearing prolegs on the ventral surface, the terminal pair being larger and with crochets opposable to those of the other prolegs. The posterior spiracles are borne on a long respiratory tube which bifurcates posteriorly.

Discussion. Neoephydra is the generic name for most South American species that had been placed in the genus “ Dimecoenia . ” As noted by Steyskal (1970) and Wirth (1971), the Neotropical species, which were treated as members of Dimecoenia ( Wirth 1968) , are structurally dissimilar from the Nearctic species. We came to the same conclusion as Steyskal and Wirth after studying structures of the male terminalia. A more complete diagnosis is given in the generic and species group's descriptions. Particular attention should be paid to structures of the male terminalia and female ventral receptacle.

Species groups are also being recognized (the araucaria , dasycephala , and neotropica groups). These groups are proposed for specimens that are dissimilar superficially from the typical Neoephydra (the araucaria group) but which have structures of the male and/or female terminalia that closely resemble those of other similar aggregates. We chose the informal category of “species group” for these subtaxa because of its flexibility, without encumbering additional, fixed nomenclature, such as would be required for the subgeneric category.

The monophyly of Neoephydra is established by the following characters: Conformation of the male terminalia: The surstyli are fused medially except near their apices and each surstylus bears one or two additional, anterolateral prongs. This conformation is unique within the subfamily. Conformation of female ventral receptacle: All species groups have a small, papilla-like operculum, which is also unique to females of Neoephydra .

It is also probable that the species groups of Neoephydra are monophyletic, although the araucaria group lacks characterization by derived character states. The monophyly of the remaining groups is well founded as evidenced by the appropriate characterization heading each group treatment.