Tortopsis, Molineri, Carlos, 2010

Molineri, Carlos, 2010, A cladistic revision of Tor top us Needham & Murphy with description of the new genus Tortopsis (Ephemeroptera: Polymitarcyidae), Zootaxa 2481, pp. 1-36 : 22-23

Tortopsis gen. nov.

Tortopus Needham & Murphy (in part), 1924: 23; Ulmer (in part), 1933: 197; Traver (in part), 1950: 596; McCafferty, 1975: 489; Scott et al. 1959; Molineri 2008

Type-species: Campsurus unguiculatus Ulmer , original designation.

Species composition: T. bruchianus , T. limoncocha sp. nov., T. obscuripennis , T. parishi , T. primus , T. puella , T. sarae , T. spatula sp. nov.

Adult: fore legs of male normal, remaining legs of male and all legs of female distorted and non-functional. Mesosternum: furcasternal plates approximating each other on basal half ( Fig. 54 ) so furcasternal longitudinal impression narrow almost entirely, becoming wider only near posterior margin. Female pronotum with anterior ring well developed, at least 1/3 of total length of pronotum. Wings sexually dimorphic, all veins of female thickened; posterior margin of hind wings of female with a reticulated pattern of veinlets. Female fore wing without R3 and short intercalary vein before it (similar to Fig. 44 ), in some large females one or both forewings may show 1 or 2 weak veins in this area, but their aspect is different (thinner, weaker) from the other longitudinal veins, as they are formed by the coalescence of few crossveins. Abdomen. Female abdominal sternum VIII with relatively large sublateral parastyli receptors, sockets opening towards the median line of the sternum ( Figs. 46, 51 ). Male genitalia: abdominal sternum IX entire ( Fig. 57 ); large parastyli present, curved dorsally, more than 5 times the length of their bases (pedestals); penes cylindrical, long and slender, completely divided ( Fig. 57 ); apex of penes with a hooked (or rarely blunt) sclerotized spine ( Fig. 59 ). Penial arms formed by a single transverse bar which is articulated to the posterior corners of tergum IX. Forceps two-segmented, basal segment short and small, with a ventral knob ( Figs. 57 ); distal segment long, slender and clublike.

Nymph (for a complete characterization see Molineri 2008): head with prominent frontal ridge ( Fig. 96 ); fronto-clypeal region expanded and concave, extending ventrally beyond mandibular tusks; mandibular tusks long with a large subapical denticle on inner margin ( Fig. 96 ); maxilla with a basal finger like gill. Large filtering setae present on mouthparts and fore legs. Legs modified for burrowing with robust segments and flat tibiae. Fore tibia-tarsus with a prominent distal projection (dorsal projection 2/3 the length of the claw). Abdomen with vestigial unilamellate gill on segment I, gills on segment II–VII normal (large and bilamellate).

Eggs. Hemispherical, bowl-shaped ( Figs. 79–80 ). Length, 355–450 µm; width, 290–375 µm. No polar caps or attachment structures; only one species ( T. spatula sp. nov.) with a long filament coiled along the main axis of the egg ( Figs. 79–80 ). Chorion with microsculptures consisting of slightly elevated pentagonal and hexagonal cells, or shallow subcircular grooves.

Discussion and diagnosis. The adults of Tortopsis gen. nov. can be separated from its sister taxon Tortopus by: 1) mesofurcasternal plates approximating each other basally and medially, with inner margins diverging only on distal half ( Figs. 45 , 54 ); 2) male abdominal sternum entire ( Figs. 57 , 73 ); 3) parastyli very long, more than 5 times the length of pedestals ( Figs. 57–58 ); 4) penes cylindrical at least basally and completely divided ( Fig. 57 ); 5) female fore wing without R3 and short intercalary before it ( Fig. 44 ), rarely expressed as 1 or 2 weak short veins; 6) parastyli receptors on abdominal sternum VIII relatively large and sublateral in position ( Figs. 46–52 , 75, 78 ), openings towards medial line. As mentioned previously, the characters distiguishing Tortopus and Tortopsis from the other genera of the family are listed in the phylogenetic section (apomorphies of node c). The coupling system in Tortopsis , as described in McCafferty & Bloodgood (1989), involves very well developed male parastyli and female sockets.

Figures

FIGURES 53 – 59. Tortopsis limoncocha. 53, male head, v. v.; 54, male mesofurcasternal plate; 55, female abdominal sternum VIII, l. v.; 56, same, v. v.; 57, male genitalia, v. v.; 58, same, l. v.; 59, detail of apex of penes.

FIGURES 44 – 52. Tortopsis, female imago. 44, T. obscuripennis, fore wing. T. sarae: 45, mesofurcasternum; 46, abdominal sternum VIII, v. v.; 47, same, l. v. T. obscuripennis: 48, abdominal sternum VIII, l. v. T. primus: 49, abdominal sternum VIII, l. v. T. puella: 50, abdominal sternum VIII, v. v.; 51 – 52, same, l. v.

FIGURES 93 – 96. Polymitarcyidae, nymphal head: 93, Asthenopus sp.; 94, Campsurus near violaceus; 95, Tortopus harrisi; 96, Tortopsis obscuripennis.

FIGURES 73 – 80. SEM photographs. Tortopsis limoncocha: 73, male genitalia, v. v.; 74, apex of penes, detail; 75, female abdominal sternum VIII, detail of left socket; 76, egg. Tortopsis spatula: 77, male genitalia, v. v. and detail of apex of penes; 78, female abdominal sternum VIII, detail of left socket; 79, egg; 80, egg, thread partially uncoiled.