Chironomus (Benthalia) hamatus ( Freeman, 1957 ) Ekrem & Technology & Museum & History & Trondheim & Email, 2016

Ekrem, Torbjørn & Elisabeth Stur, 2016, NEW COMBINATIONS OF AFROTROPICAL CHIRONOMINI (DIPTERA: CHIRONOMIDAE) Abstract, CHIRONOMUS Journal of Chironomidae Research 29, pp. 4-10 : 4-5

Chironomus (Benthalia) hamatus ( Freeman, 1957) comb. n.

http://zoobank.org/ F9A669AB-EE75-4C5A-ABB5-C58DA7091109

Chironomus (Endochironomus) hamatus Freeman, 1957: 355 .

Endochironomus hamatus ( Freeman, 1957) , Freeman and Cranston (1980).

Material examined: 1 paratype male ( NHMUK), Democratic Republic of the Congo, Elisabethville , 30.iii.1939, H.-J. Brédo.

The examined male paratype shows characters typical of the Chironomus group of genera: antenna with 11 flagellomeres, medially fused antepronotal lobes, inferior volsella subcylindrical with dense apical setae. Unfortunately, the slide-mounted hypopygium ( Figs 1a, b ) is quite distorted, but the almost parallel-sided gonostylus without subapical constriction, anal tergite bands that meet medially in front of and not encircling median tergite setae, and the shape of the superior volsella resembles what is known from Benthalia Lipina ( Shilova 1980 sub Einfeldia carbonaria (Meigen, 1804) , Saether 2012). Moreover, the specimen has large barrel-shaped frontal tubercles ( Figs 1c, d ) characteristic of Benthalia ( Shilova 1980, fig. 8A 2). In addition there is a smaller pair of warts on the anterior part of vertex, dorsolaterally with respect to the frontal tubercles. A similar arrangement has been recorded for Tanytarsus epleri Ekrem et al., 2003 . For this species the pupa has large frontal warts in addition to enlarged frontal tubercles ( Ekrem et al. 2003), thus similar structures might be present in the unknown pupa of Chironomus (B.) hamatus .

Some authors regard Benthalia a separate genus (e.g. Saether and Spies 2013, Yamamoto and Yamamoto 2014), while Epler et al. (2013) regard Benthalia as possible subgenus of Chironomus Meigen along with Fleuria Kieffer , Baeotendipes Kieffer , Chaetolabis Townes and Lobochironomus Ryser, Wülker & Scholl. Molecular phylogenies are inconclusive for the group placement of Benthalia ( Martin et al. 2007 sub Lobochironomus dissidens = Benthalia carbonaria ), but indicate a closer relationship to species in Chironomus sensu stricto. Until conclusive data that are provided, preferably through molecular systematic studies with wide sampling of Chironomus species and relatives, we regard Benthalia as a subgenus of Chironomus .

Figures

Figure 1. Chironomus (Benthalia) hamatus. Paratype male: a) gonocoxite and gonostylus (slightly crushed subapically); b) hypopygium remains; c) Head; d) Head section showing frontal tubercles and warts. Scale bars = 100 µm.