Dipseudopsis Walker

Oláh, János & Johanson, Kjell Arne, 2010, Contributions to the systematics of the genera Dipseudopsis, Hyalopsyche and Pseudoneureclipsis (Trichoptera: Dipseudopsidae), with descriptions of 19 new species from the Oriental Region., Zootaxa 2658, pp. 1-37 : 3-4

Dipseudopsis Walker

Dipseudopsis Walker, 1852: 91 . Type species: Dipseudopsis capensis Walker, 1852: 91 (monotypic); type locality: South Africa (Port Natal).

Bathytinodes Iwata, 1927: 209. Type species: Bathytinodes alba Iwata (monotypic); type locality: Japan. Synonym according to Tsuda, 1942: 266.

Dipseudopsodes Lestage, 1936: 170. No type species designated. Invalid according to Fischer, 1962: 3.

Esperona Navás, 1915: 397. Type species: Esperona orientalis Navás (monotypic); type locality: Vietnam ( Tongking). Synonym according to Lestage, 1925: 39.

Nesopsyche McLachlan, 1866: 268. Type species: Nesopsyche flavisignata McLachlan (monotypic); type locality: Sulawesi (Celebes). Synonym according to Mosely, 1933: 499.

The genus Dipseudopsis Walker is remarkable in having siphoning mouthparts and conspicuous sexual dimorphism. Many males and females have contrasting colour patterns in their wings and bodies. Males have twisted and/or branched mesoapical spurs on their hind tibiae. The proboscis siphoning organ is formed by the elongate terminal lobes of the maxillae which are probably the laciniae. The galeae are reduced and suppressed. The elongate laciniae are not held together in preserved specimens, but variously curled away from each other distally. The sucking apparatus is operated by a stomodaeal pump and positioned by the cranial and stipital flexor muscles. The apparatus in use has not yet been observed. However, a pollinium attached to the mouthparts of a male D. doehleri Ulmer, 1929 , was discovered (John S. Weaver III, personal communication), indicating that the species might feed on flowering plants. The enlarged stipital flexor muscles are inserted on the bases of the laciniae. The presence of a proboscis resulted in 2 characteristics of the head: 1) the extreme enlargement of the stipes serving for attachment of the stipital flexor muscle, and 2) the highly convex and enlarged clypeus covering the stomodaeal pump.

An additional feature of the genus is the presence of glabrous cephalic and thoracic surfaces. The setal areas are not elevated into typical setaceous warts but are flush with surrounding sclerites ( Weaver & Malicky 1994). The typical setal warts are present. A detailed description of the cephalic groove and setal wart patterns and tentorium of Dipseudopsis oliveri , new species is provided herein, and only minor specific alterations are observed in the other species. Based on the observations of the un-cleared head of various species, we conclude that the cephalic groove and setal wart patterns are stable and persistent in Dipseudopsis .

The new species in Dipseudopsis described below share the following characters, except when stated otherwise.

Adult. Head shorter than wide. Antennae stout, about as long as each forewing; scapes short, half as long as head, almost touching; distance between antennae shorter than length of each scape; membranous antennal sockets large, depressed, wrinkling with scape movements, delineated by elevated, strongly sclerotized rim of antennal and frontal grooves. Eyes small, interocular distance on vertex more than 2 times longer than eyes. Maxillary palp formula I-IV-II-III-V; first 3 segments dilating apically. Stipes moderately large. Labrum bipartite, basal part transversally elongate, quadrangular; sclerotized; fused with clypeus, fixed; apical portion membranous, flexible, hanging freely. Enlarged bulging clypeus sparsely covered by setae. Frons narrowing posteriorly from above theoretical line of frontoclypeal groove (epistomal suture) between anterior tentorial pits; stretching posterad between scapes. Subgenal process forming narrow tapering, dark tooth. Two branches of frontal grooves visible on face and on head dorsum, delineating frons, stretching between membranous antennal sockets. Short, sinuous frontogenal and long clypeogenal grooves well-pigmented; clypeolabral grooves weakly discernible. Proboscis longer than first 4 segments of maxillary palps. Haustellum reduced, forming narrow band with bifid apex. Coronal groove visible along entire vertex. Basal sclerotized part of labrum and entire clypeus covered with short setae; remnant of frontal setal warts shifted posterad and dorsad between scapes, nearly invisible, represented by few setae; pair of setose warts, probably representing vertexal interantennal warts, attached to rim of antennal sockets. Occipital and postgenal setal warts compact and setose. Setose wart attached to dorsum of anterior arm of each cervical sclerite, central ridge of cervical sclerites covered by long setae.

Thorax. Pronotum raised to head level, divided by deep longitudinal furrow; raised surface sparsely covered with short setae or alveoli. Setal warts on mesonotum variable (see below). Metanotum without setal warts. Spur formula 2, 4, 4. Claws on all legs symmetrical.

Remarks. In making species identifications of Dipseudopsis , the precise orientation of the modified hind leg spur is a crucial factor, because slight rotation of the tibiae produces different perspectives of the spur ( Weaver & Malicky 1994). Here we chose the left leg and ventral view for examination and drawing, and we illustrated the modified spur together with the adjacent anteroapical unmodified spur and a part of both tibia and tarsus. Similarly, the drawings of the large, preanal appendages are auriform and sensitive to observation angle, especially in dorsal view. We illustrate the more stable lateral views herein. The male genitalia are rather blunt and often lack conspicuous characters. We found the sclerotized structures of the phallocrypt, or the mesosuperior processes of sternum IX ( Weaver & Malicky 1994), useful in differentiating species. This structure may possibly represent the paraproctal processes (intermediate appendages) fused at the extreme base of the basodorsal bulging corners of sternum IX, and hinged with tergite IX and the preanal appendages. Their lower inner angles extend medially into a bridge around and under the phallobase. This character is often difficult to observe because often it is weakly sclerotized and the heavily sclerotized sternum IX and inferior appendages obstruct it from view. However, removing the inferior appendages and the apodeme exposes the mesosuperior processes (paraproctal process) in caudal view.

Ross & Kingsolver (1959) speculated about the phylogeny of the genus, and postulated the length of forewing veins R2 and R3 as well as the shape of inferior appendages in ventral or caudal views for recognition of proposed phylogenetic lines. After more species were examined and described ( Weaver & Malicky 1994), the length of forewing R2 and R3 of fork I proved to be unstable, between and within species, and a plesiomorphic character. For instance, the stalk/fork R2+3 ratio varies in the range of 2–10 in D. rathnotoia , new species.