Afrolimna keiseri (Cogan)

Comprehensive Description

provided by Smithsonian Contributions to Zoology
Afrolimna keiseri (Cogan)

Paralimna (Afrolimna) keiseri Cogan, 1968:323; 1980:662 [Afrotropical catalog].—Mathis and Zatwarnicki, 1995:118 [world catalog].

DIAGNOSIS.—This species is distinguished from Afrolimna carolinika by the characters indicated in the key and by the following characters from the male terminalia (Figures 9–11): epandrium broadly and uniformly U-shaped in posterior view (Figure 9), lateral arms slightly wider; cercus moderately broad ventrally, pointed anteriorly; presurstylus angulate in posterior view (Figure 9), elbowed, medially oriented arm only slightly wider than vertical portion, medial surface truncate and with 90° dorsomedial angle not projected; postsurstylus in lateral view curved, slightly widened medially, thereafter narrowed, apex shallowly bifurcate; aedeagal apodeme with prominent keel, keel irregularly rounded and bearing long, almost parallel-sided medial projection longer than width of keel; aedeagus wider basally, gradually narrowed to broad, angulate apex in lateral view (Figure 10); lateral aedeagal process shorter than aedeagus in lateral view, tapered to acute point apically; and hypandrium angulate, moderately shallow.

TYPE MATERIAL.—The holotype male of Paralimna keiseri Cogan is labeled “Holo-type [round label with red margin]/Madagascar [Toliara] Sud Sept-Lacs 100m dct Tuléar 13–16.II.58 B. Stuckenberg.” The holotype is double mounted (minuten in a rectangular block of polyporus), is in good condition, and is deposited in the NMSA. Six paratypes (2, 4; BMNH) bear the same locality data as the holotype.

OTHER SPECIMENS EXAMINED.—Afrotropical. MADAGASCAR. Toliara: South Berenty Reserve, 20 Apr 1991, A. Freidberg, F. Kaplan (2; USNM).

DISTRIBUTION.—Afrotropical: Madagascar.

Corythophora Loew, 1862b: 13 [type species: Corythophora longipes Loew, 1862, monotypy].—Bezzi, 1908a:195 [synonymy with Dryxo Robineau-Desvoidy].

Karema Cresson, 1929:182 [type species: Karema loewella Cresson, 1929 (=Corythophora longipes Loew), original designation].—Cogan, 1968: 356–358 [revision]; 1980:661 [Afrotropical catalog].—Mathis and Zatwarnicki, 1995:116–117 [world catalog]. [New synonym.]

DIAGNOSIS.—This genus is distinguished from other genera of Dryxini, especially Dryxo, which is similar, by the following combination of characters: ocellar seta present, although short, inserted slightly in front of anterior ocellus; reclinate fronto-orbital seta present; notopleuron bearing 1 large seta; presutural supra-alar seta lacking; anepisternum with 1 well-developed seta along posterior margin; katepisternal seta reduced and lacking row of slender setae along dorsal margin; vein R1 bare along dorsum; R stem vein lacking setulae; vein R node bearing 3–5 setulae on dorsum; crossvein dm-cu normally developed, nearly straight, forming nearly 90° inner angle with vein M; forefemur of both sexes lacking row of short, peg-like setulae apically along anteroventral surface; and mid- and hindfemora elongate, subequal to length of abdomen.

DESCRIPTION.—Medium-sized to large shore flies, body length 3.40–6.60 mm.

Head: Frons shallowly arched anteroventrally, not projected forward, sparsely setulose; ocelli in isosceles triangle, distance between posterior pair shorter than between anterior ocellus and either posterior ocellus; inner vertical seta and reclinate fronto-orbital seta well developed; ocellar and paravertical setae weakly developed or absent. First flagellomere acutely rounded; arista bearing 10–14 long hairs along length of dorsal surface. Face lacking conspicuous facial setae. Parafacial at anterior margin of eye narrow, width much less than length of 1st flagellomere. Gena high, height subequal to combined length of 1st flagellomere and pedicel.

Thorax: Anterior dorsocentral setae lacking, only posteriormost pair present (0+1); acrostichal setulae poorly developed, inconspicuous, in 2 rows; presutural supra-alar seta lacking; postpronotal seta well developed; notopleural seta 1; anepisternum bearing 1 large seta at posterior margin, dorsal seta lacking; katepisternal seta weakly developed, hair-like. Posterior margin of scutellum broadly rounded. Wing with apex of costa at subcostal break bearing 2 short, stout setae; vein R1 bare along dorsum; R stem vein lacking setulae; vein R node bearing 3–5 long, pale setulae on dorsum; crossvein dm-cu regularly developed, nearly straight, longer than apical section of vein CuA1, and at distinct angle with adjacent margin of wing. Forefemur of male lacking comb-like row of short, stout, tooth-like, sometimes flattened setae along apical of anteroventral surface; foretibia of male lacking several long, slender setae at apex on ventral surface; midtibia bearing 4 dorsal extensor setae (basally, subbasally, subapically, and apically); mid- and hindfemora greatly elongate, subequal to length of abdomen; midtibia bearing 2 ventroapical setae and 1 posteroapical seta; foretarsus with mostly cylindrical tarsomeres, not distinctly flattened; forebasitarsus lacking row of long, slender, pale setulae inserted along anterior surface.

Abdomen: Coloration with distinctly fasciate pattern. Male terminalia: cercus ovoid to allantoid, bearing numerous setulae along medial margin; presurstylus a narrow, band-like process at ventral margin of cercus; aedeagus in lateral view wide basally, at midlength narrowed to slender process; aedeagal apodeme elongate, with long process extended beyond portion bearing keel and with secondary, short process extended externally at about midlength; hypandrium wide and robust, lateral margin with emargination and processes.

HISTORICAL REVIEW.—Corythophora, as a generic name, has been largely overlooked until now. For more than 90 years, Corythophora was treated as a junior synonym of Dryxo (Bezzi, 1908a). This oversight, which was perpetuated in the literature, is typical of interpreting a written description without studying the primary types. Limited or essentially no access to the types of Corythophora longipes Loew was undoubtedly the primary impediment to recognizing the identity and thus the nomenclatural precedence of Corythophora. Like Bezzi, Cresson (1929) also did not examine Loew's type series, and he and all subsequent authors have accepted Bezzi's determination that Corythophora was a junior synonym of Dryxo. As a result, most previous treatments of the species included in Corythophora since Bezzi were published under the name of Karema (Cresson, 1929; Wirth, 1956, 1960; Cogan, 1968, 1980; Canzoneri and Raffone, 1987; Canzoneri and Rampini, 1994; and Mathis and Zatwarnicki, 1995). Of these treatments, Cogan's revision (1968) was the most comprehensive and included illustrations.

We borrowed and studied Loew's type and here consider Corythophora to be the senior synonym of Karema Cresson, as the type species for both generic names, Corythophora longipes Loew and Karema loewella Cresson, are conspecific.

DISTRIBUTION (Figure 12).—Afrotropical: Angola, Botswana, Cameroon, Chad, Ethiopia, Ghana, Kenya, Madagascar, Malawi, Namibia, Nigeria, Sierra Leone (Northern Province: Bumbuna), South Africa (Cape Province, Natal, Transvaal), Sudan, Swaziland, Tanzania, Zaire, Zimbabwe.

PHYLOGENETIC RELATIONSHIPS.—Cresson (1929:182) suggested that Corythophora (as Karema) is related to Dryxo and is a “connectant” between the latter and Paralimna. He also made a comparison with the genus Parydra Stenhammar. Although the latter relationship with Parydra is untenable, being based on convergent characters, Cresson's primary suggestion is confirmed and further documented by our research. Dryxo, with Omyxa as its immediate sister group, forms a lineage that is the sister group to Corythophora.

Unambiguous autapomorphies for Corythophora are (1) anepisternum with 1 large seta at posterior margin; (2) katepisternal seta reduced; (3) vein R node bearing 2–3 long, posteriorly directed setulae on dorsum; (4) adeagal apodeme with long projection extended from near articulation with hypandrium; (5) midtibia bearing 4 erect setae along dorsum; and (6) posterior margin of scutellum broadly rounded.
bibliographic citation
Mathis, Wayne Neilsen and Zatwarnicki, Tadeusz. 2002. "A phylogenetic study of the tribe Dryxini Zatwarnicki (Diptera:Ephydridae)." Smithsonian Contributions to Zoology. 1-101. https://doi.org/10.5479/si.00810282.617