Pseudoaerumnosa Rudzinski, 2006

Vilkamaa, Pekka, Halenius, Pentti & Ševčík, Jan, 2019, Review of Pseudoaerumnosa Rudzinski (Diptera, Sciaridae), with the description of twenty-four new species, Zootaxa 4656 (1), pp. 1-42 : 2-4

The genus Pseudoaerumnosa Rudzinski, 2006

Redescription. Male. Small to medium-sized Sciaridae , wing length 1.4–3.5 mm.

Head. Brown, face concolorous with antenna. Eye bridge 1–4 facets wide. Face with 1–25 setae. Mouth parts strongly reduced, clypeus non-setose ( Rudzinski 2006: Figs. 62, 64). Antennal scape and pedicel normal. Antennal flagellum with 14 flagellomeres, body of flagellomeres asymmetrical, frontal part larger, with distinct apical margin, with dense, short and curved setosity, setae shorter than width of the flagellomeres; with some rod-like sensilla, neck of flagellomeres shorter than wide, body of 4th flagellomere 1.3–2.3x as long as wide in frontal view ( Fig. 1 B, C ). Mouthparts reduced; maxillary palpus with one segment, with 1–6 pointed setae, with a dorsal patch of long sensilla ( Rudzinski 2006: Fig. 62, 64, 65).

Thorax. Brown; setae dark. Notum with many short laterals, with robust dorsocentrals. Postpronotum with some setae, anterior pronotum with 1–11 setae, proepisternum with 1–8 setae. Scutellum with 2 or 4 moderately long and many short setae. Wing ( Figs 2 , 3 ). Fumose. Normal, broad (width/length 0.45–0.60), anal lobe variable. Veins distinct, R1 longer than R, joining before, at or beyond base of M-fork. Wing membrane non-setose, hind margin with dorsal setae, in some species also with ventral setae. Veins C and R5 with dorsal and ventral setae, R1 with dorsal setae, with or without ventral setae, bM and stCu non-setose, r-m non-setose or (rarely) with 1–2 setae. c/w 0.55–0.90, R1/R 1.15–2.65. Haltere with short stem. Legs. Yellow or pale brown, slender, setae dark. Tibial spurs 1:2:2. Fore tibial spur as long as or slightly longer than the subapical width of tibia. Left and right spurs of mid and hind tibia subequal. Tibiae without distinct spinose setae. Fore tibial organ unmodified, with a few slender setae only ( Fig. 1 A ; Rudzinski 2006: Fig. 66). Tarsal claws simple, without teeth. Abdomen. Pale brown; plump, setae long, dark, and robust. Hypopygium. Brown, like the abdomen; setae robust and dark. Gonocoxa longer than or as long as gonostylus. Gonocoxae basomedially fused, intergonocoxal area broad and short, without lobe(s), with or without microtrichia, medially with or without non-setose area ( Fig. 4 ), ventromedial margin distinct, semicircular or U-shaped. Gonocoxa with strongly sclerotized apical margin, with long setosity, setae slightly shorter at medial margin, apicomedial seta well developed or indistinguishable from surrounding setae, in most species microtrichosity restricted to basal and lateral parts. Gonostylus ventrally and dorsally impressed or not impressed, with sclerotized basolateral apophysis, with a medial lobe, variably developed in the species, or medial side of gonostylus broadly lobe-like produced, the lobe or lobe-like medial side with 2 to 12 megasetae; megasetae slender, hyalinous and nearly straight or curved; with long apical tooth with a distinct basal part, both dark, apical tooth with small megaseta attached to its basoventral side; with rich setosity, usually with some narrow elongated setae on the apical and basal/basoventral side of the tooth, microtrichosity restricted to basolateral parts. Tegmen without basal sclerotization, laterally variably sclerotized, smoothly roundish or curved or acuminate, hyalinous apically, in some species microtrichose, with or without apical finger-like process; with tiny aedeagal teeth in groups, basal apodemes short. Aedeagal apodeme usually distinct.

Female. Unknown.

Distribution. Madagascar, Oriental Region, Papua New Guinea.

Discussion. Pseudoaerumnosa can be distinguished from other genera of Sciaridae by the following combination of characters: plump abdomen, maxillary palpus 1-segmented with a dorsal patch of sensilla, antennal flagellomeres asymmetrical with the frontal part larger (unique among the known Sciaridae ) and with short curved setosity, the apical tooth of the gonostylus with broader basal part and a longer, narrower apical part with a short megaseta attached to the ventral side (such megasetae are also present in some species of Mohrigia Menzel described by Rudzinski (2006)); a medial (not dorsal or ventral) lobe on the gonostylus (a medial lobe is present in some species of Scatopsciara (Xenopygina) Frey ); hyaline, at least slightly curved gonostylar megasetae (hyaline megasetae present in various genera); a broad hypopygium with a short and evenly broad intergonocoxal area formed by the united gonocoxae (found also in Cratyna Winnertz ); unmodified fore tibial organ (an unmodified tibial organ is also present in Epidapus Haliday and Xylosciara Tuomikoski ); tibiae without distinct spinose setae; a broad wing, a long wing vein R1 (always longer than R; a long R1 is also present in Cratyna Winnertz , Scythropochroa Enderlein and Trichosia (Mouffetina) Frey and in various undescribed groups of Sciaridae ). Pseudoaerumnosa also always has a long c/w ratio. Like the subgenera of Cratyna , Pseudoaerumnosa has setae on the postpronotum, although, if broken, their sockets may be difficult to detect in normal slide mounts. Furthermore, the colouration in most species is yellow or pale brown, contrasting strongly with the dark and robust setosity.

Phylogenetic characters of Pseudoaerumnosa . Rudzinski (2006) postulated a close relationship between Pseudoaerumnosa and Aerumnosa Mohrig on the basis of reduced mouthparts (labrum, labellum and maxillary palpus); a long wing vein R 1 in relation to R; R1 and R5 with ventral setae in addition to the usual dorsal ones, and a wide gonostylus with a group of mesial megasetae. However, the morphology of Aerumnosa differs strikingly from Pseudoaerumnosa in many characters: the body is larger, the whole hypopygium is highly modified with complex structures of the gonocoxa, gonostylus and tegmen, the antenna is unmodified and the fore tibial organ is large with a dense patch of setae (see Mohrig 1999).

Based on a phylogenetic analysis using four gene markers, ( COI, 16S, 18S and 28S) as characters, Vilkamaa et al. (2018) suggested that both Aerumnosa and Pseudoaerumnosa belong to the Cratyninae sensu Shin et al. (2013), with Peyerimhoffia Kieffer as the sister group of Pseudoaerumnosa .

Diagnostic characters of Pseudoaerumnosa . Regarding morphology, Pseudoaerumnosa shares with Cratyna s.l. a plump abdomen, a broad hypopygium, a reduced maxillary palpus, a setose postpronotum, a short gonocoxa and the lack of robust spinose setae on the tibiae. Some species of Pseudoaerumnosa have a finger-like process on their tegmen, like many species of Cratyna s. str. and some Spathobdella Frey (see Menzel & Mohrig 2000; Hippa et al.1998). Pseudoaerumnosa shares with Cratyna (Peyerimhoffia) and with Cratyna (Spathobdella) a reduced maxillary palpus and a modified apical tooth of the gonostylus with a megaseta or megasetae, although the megaseta in Pseudoaerumnosa is attached to the ventral side of the tooth, not inside of it, as in Peyerimhoffia and Spathobdella (and in the Corynoptera crassistylata group).

Furthermore, Pseudoaerumnosa is actually morphologically more similar to Cratyna (Spathobdella) than to Cratyna (Peyerimhoffia) in having the apical tooth with a broad basal part and a narrow apical part, the gonostylar megasetae of the similar hyalinous type, in having long slender setae apically and subapically on the gonostylus and in having a weakly sclerotized tegmen without basal sclerotization. Pseudoaerumnosa differs from Spathobdella in having the gonocoxae united, not separate, in lacking specialized setae apically on the gonostylus (on the dorsal side) and in having the antennal flagellomeres asymmetric, only a few setae in the fore tibial organ and the attached megaseta on the apical tooth of the gonostylus.

Figures

FIGURE 1. A. Apical part of fore tibia, prolateral. B. 4 th antennal flagellomere, frontal. C. 4th antennal flagellomere, lateral. A: Pseudoaerumnosa obovata sp. n. (paratype from Ladan). B, C: P. clavidactyla sp. n. (paratypes from Danum Valley). Scale 0.10 mm.

FIGURE 2. Wing, dorsal.A: Pseudoaerumnosa banari sp. n. (paratype). B: P. eminula sp. n. (paratype from Ulu Temburong). C: P. fragilis sp. n. (holotype). D: P. tenuidens sp. n. (holotype). E: P. consuota sp. n. (paratype). F: P. junciseta sp. n. (paratype). Scale 1.0 mm.

FIGURE 3. Part of hind margin of wing, dorsal. A: Pseudoaerumnosa fragilis sp. n. (holotype). B: P. tenuidens sp. n. (holotype). Scale 0.10 mm.

FIGURE 4. Intergonocoxal area, ventral. A: Pseudoaerumnosa banari sp. n. (holotype). B: P. consuota sp. n. (holotype). C: P. fragilis sp. n. (holotype). D: P. tenuidens sp. n. (paratype from Sabah, Mainline West). Scale 0.10 mm.