Tanypus urszulae Silva
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|Tanypus urszulae Silva|
Tanypus urszulae Silva sp. nov.
Type material: Holotype male with pupal and larval exuviae, BRAZIL: São Paulo, São Carlos, Monjolinho reservoir, 48°05’00”W, 22°06’00”S, 19.ii.2001, leg. C.S.N. OliveiraGoogleMaps . Paratypes: 1 pharate male with larval exuviae, same data as holotype except 16.ii.2001GoogleMaps .
Etymology. Named in honor of Urszula Miezio from Philadelphia, in recognition of her friendship, kindness and continuous support.
Diagnosis. Tanypus urszulae sp. nov. differs from other Tanypus species by the combination of the following characters. Adult male: abdominal tergites pale brown, evenly colored; maxillary palp 4-segmented; scutal tubercle raised; hypopygium with curved gonostylus, carina reduced. Pupa: A II –VI without fringe, A VII with 6 LS; anal lobe paddle-like. Larva: ligula with six teeth.
Description. Male (n = 2, except where otherwise stated).
Size. Total length 4.2 (1) mm. Wing length 1.7 (1) mm. Total length/wing length 2.53 (1). Wing length/ profemur length 2.10 (1).
Coloration. Head pale brown with occipital margin darkened; pedicel and antenna brown; maxillary palp pale brown. Thorax golden brown with antepronotum pale; scutal tubercle lighter than surrounding area. Wing membrane transparent with several dark spots; cross-veins RM and MCu darkened ( Fig. 2View FIGURES 1 – 7). All legs femora with subapical dark band, tibia with subbasal and apical bands, ta1–ta3 each with apical band, ta4-5 almost entirely dark. Abdomen ( Fig. 6View FIGURES 1 – 7) pale brown, hypopygium darker.
Head ( Fig. 1View FIGURES 1 – 7). Temporals 14 (1), uniserial. Eye ratio 1.06 (1). Tentorium 232 (1) µm long. Clypeus 85 (1) µm long, 89 (1) µm wide at largest part, bearing 14 (1) setae. Cibarial pump 153 (1) µm long, with anterior margin concave. Palp consisting of 4 palpomeres, first palpomere often indistinct. Lengths of palpomeres 2–4 (µm): 45 (1); 56 (1); 107 (1). Antennal flagellum 1142 (1) µm long, diameter of pedicel 93 (1) µm, apical setae single, AR 1.91.
Thorax. Antepronotals not observed. Scutal tubercle distinct and oval. Acrostichals 32 (1), uniserial between median vittae, diverging posteriorly; dorsocentrals 15 (1); prealars 6 (1); supraalars 1 (1). Scutellars 10 (1).
Wing ( Fig. 2View FIGURES 1 – 7). Width 0.6 (1) mm. Costa produced, reaching apex of wing, 1.6 (1) mm long. VR 1.19 (1). WW 0.34 (1). Wing membrane apically with setae. Squama with 28 (1) setae.
Legs ( Figs 3–5View FIGURES 1 – 7). Fore-tibia 50 (1) µm wide at apex, bearing single, apical spur 49 (1) µm long, with 2 lateral teeth ( Fig. 3View FIGURES 1 – 7). Mid tibia 67 (1) µm wide at apex, bearing 2 apical spurs 43 (1), and 46 (1) µm long, each with 2 lateral teeth ( Fig. 4View FIGURES 1 – 7). Hind tibia 67 (1) µm wide at apex, bearing 2 apical spurs 50 (1), and 60 (1) µm long, with 2 and 3 lateral teeth, respectively ( Fig. 5View FIGURES 1 – 7); comb with 8 (1) bristles. All ta1-4 without any pseudospurs. Claws distally spatulate. Lengths and proportion of leg segments as in Table 1.
Hypopygium ( Fig. 7View FIGURES 1 – 7). Tergite IX with 14 posterior setae. Phallapodeme 68–77 µm long. Gonocoxite broad, cylindrical, 149–174 µm long, 101–122 µm wide at base, with slightly concave inner margin, bearing many dorsomedial robust setae. GcR 1.43–1.47. Gonostylus 105–121 µm long, with 3–4 inner setae; carina reduced, and megaseta 12–13 µm long. HR 1.42–1.45. HV 1.12 (1).
Pupa (n = 2, except where otherwise stated).
Coloration. Exuviae mostly pale brown; thoracic horn brown.
Cephalothorax ( Figs 8–9View FIGURES 8 – 11). Frontal apotome triangular, weakly rugose ( Fig. 8View FIGURES 8 – 11). Wing sheath smooth, 0.9–1.1 mm long. Thoracic horn ( Fig. 9View FIGURES 8 – 11) globose, asymmetrically biconvex, 425–524 µm long, THR 1.24–1.54; external membrane extensively rugose, with narrow apical neck. Thoracic comb consisting of weak tubercles, extending anteroventrally from horn base.
Abdomen ( Figs 10–11View FIGURES 8 – 11). Shagreen consisting of short rounded spines, but finer and more pointed in distal segments. Segment II –VI without any setal fringe. A VII with 6 LS-setae; AVIII with 5 LS-setae. Anal lobe well developed, paddle-like 337–578 µm long ( Fig. 11View FIGURES 8 – 11), 2.4 times as long as median length of segment VIII, with anterior and posterior anal macrosetae located 0.34 and 0.46, respectively, from anterior margin; outer margins rounded and smooth. Male genital sac 0.3 times as long as anal lobe, not extending beyond lobe.
Fourth instar larva (n = 2, except where otherwise stated).
Coloration. Head pale yellow, with postoccipital margin brown. Abdomen pale yellow. Procercus pale brown. Posterior parapod claws all pale yellow.
Head ( Fig. 12View FIGURES 12 – 19). Trapezoidal, 461–527 µm long, 512–536 µm wide. Ventral cephalic setae S9, S10 and sensory pore (VP) arranged in straight line ( Fig. 12View FIGURES 12 – 19). Dorsal cephalic setae S7, S8 and dorsal pore (DP) forming a more or less right angle ( Fig. 12View FIGURES 12 – 19).
Antenna ( Fig. 13View FIGURES 12 – 19). Length 187–199 µm. A1 165–174 µm long, with ring organ located 0.83–0.86 from base; A 2 11–18 µm long. AR 6.87–7.49. Blade ( Fig. 14View FIGURES 12 – 19) longer than A2, not reaching apex of flagellum.
Maxilla ( Fig. 15View FIGURES 12 – 19). Basal palp segment ( Fig. 15View FIGURES 12 – 19) 58–65 µm long and 17–20 wide at middle, with ring organ located 0.68–0.71 from base. PR 2.91–3.88. APR 2.67–2.86.
Mandible ( Fig. 16View FIGURES 12 – 19). Short and compressed, 97–101 µm long. Sensillum campaniformium located 0.69–0.78 from apex. Mola protruding, bilobed apically. AMD 1.70– 1.73.
Hypopharyngeal complex ( Fig. 18View FIGURES 12 – 19). Ligula narrow, 139–145 µm long, 33–34 µm wide at base, with 6 straight teeth; teethed margin slightly convex. Paraligulae 59–64 µm long, comb-like with 4 fine branches.
Body ( Fig. 19View FIGURES 12 – 19). With fringe of lateral swim-setae. Anterior parapods with simple claws. Procercus 265–301 µm long, 77–83 µm wide, with 14 anal setae, 613–622 µm long. L/W 3.20–3.9. Posterior parapod apically with many simple claws ( Fig. 19View FIGURES 12 – 19).
Remarks. The male of Tanypus urszulae sp. nov. closely resembles those of T. (Apelopia) imperialis Sublette and T. (Apelopia) neopunctipennis Sublette in having dorsocentrals in a single row towards the scutellum and the curved gonostylus, but can be separated by the entirely pale brown abdominal coloration and the gonostylus with reduced carina opposing to T. (A) imperialis , which possesses abdomen with basal brown bands on each segment and T. (A) neopunctipennis , characterized by the absence of carina. Based on the adult features, scutal tubercle lighter than the surrounding area and maxillary palp composed of 4 palpomeres (see Roback 1971: 55), T. urszulae may be included in the subgenus Apelopia . The immature stages, pupa and larva, however, possess the features of Tanypus s. str. (see Roback 1977: 72), since the pupal abdomen has LS-setae only on the segments VII –VIII, and the larval claws on the posterior parapod are all simple. Thus the adult and the immatures disagree in the subgeneric status. The pupa has well-developed anal lobes which are much longer than the abdominal segment VIII. This is a unique feature among the known pupae of this genus, because all other known pupae have reduced anal lobes which are shorter than the abdominal segment VIII ( Fittkau & Murray 1986). The larva is armed with a sixteethed ligula. It is also unique among the known Tanypus larvae having a five-teethed ligula ( Cranston & Epler 2013). Tennessen & Gottfried (1983) reported the larva of T. (T.) punctipennis which possesses a six-teethed ligula. They concluded that it was an abnormal ligula, because it occurred in one of 12 larval specimens examined. Whereas in T. urszulae the six-teethed ligula was found out in all of two larval specimens examined. Considering the unique pupal morphology and the unique status in the genus, we cannot but recognize the six-teethed ligula as a larval features of the species.
Distribution and habitat. Tanypus urszulae sp. nov. is known only from its type locality, at the Monjolinho Reservoir in southeast Brazil (São Carlos, SP). This is a small aquatic system, located within the Federal University of São Carlos (UFSCar) and surrounded by monoculture of Pinus elliotti Engelmann. The reservoir is characterized by large amounts of the submerged macrophyte, Myriophyllum aquaticum (Velloso) at its margins.
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