Stempellinella lamellata, Ekrem, 2007

Ekrem, Torbjørn, 2007, A taxonomic revision of the genus Stempellinella (Diptera: Chironomidae), Journal of Natural History 41 (21 - 24), pp. 1367-1465 : 1423-1425

publication ID

https://doi.org/ 10.1080/00222930701437360

persistent identifier

https://treatment.plazi.org/id/CD7F7062-6B34-FFB8-FF2C-029682E8F943

treatment provided by

Felipe

scientific name

Stempellinella lamellata
status

sp. nov.

Stempellinella lamellata View in CoL sp. n.

Type material

Holotype: „ ( ZSM) Brazil, Est. Rio de Janeiro, Rio Cascatinha, Caledonia (Represa), Nova Friburgo , 24 August 1995, E. J. Fittkau.

Paratypes: 2 Pex as holotype; 1 „ ( UFSC) Brazil, São Paulo, Cananéia, Gruta stream, 16 February 2002, F. O. Roque; 1 Pex ( ZSM) Brazil, Iguaçú National Park , stream, 6 December 1996, F. Reiss; 1 Pex ( ZSM) Bolivia, between Coroico and Caranavi, drift in stream, 18 July 1976, E. J. Fittkau .

Etymology

The species name is an adjectival form of the Latin noun ‘‘lamella’’, meaning a small plate, and refers to the exceptionally long lamellae of the median volsella.

Diagnostic characters

Stempellinella lamellata can be separated from other Stempellinella species by the following combination of characters: male imago with AR ca 0.5; anal point long, thin, without crests; base of anal point with two median tergite setae and numerous groups of strong microtrichia; lateral anal tergite seta present; median volsella medially directed, without microtrichia, with long, anally curved lamellae which reach past apex of inferior volsella. Pupa with strongly granulose frontal apotome and thorax; thoracic horn with numerous small chaetae on distal two-thirds; hook row with ca 40 teeth; long points in patches on abdominal tergites III – VI, point patches on tergites IV – VI p -shaped; segment VIII with three lateral taeniae.

Description

Adult male (n 5 2, unless otherwise stated). Total length 0.9–1.1 mm; wing length 0.67– 0.82 mm.

Colour: non-macerated specimens pale green-brown with darker brown knees, posterior part of scutum, postnotum, posterior corner of preepisternum, median anepisternum, halteres, and small sclerite between fore coxa and preepisternum; eyes red-brown with darker ventral margin.

Head: eyes without dorsomedian elongation; frontal tubercle small, 3 Mm long; antenna ( Figure 19A View Figure 19 ) with 12–13 flagellomeres of which only 10 are easily discernible; AR (on 10 flagellomeres) 0.44–0.54; lengths of palpomeres (in Mm): 15, 15–21, 36–51, 54–72, 84 (n 51). Clypeus about 30 Mm long with 8–10 setae; tentorium ca 75 Mm long, 21 Mm wide; one inner vertical, one outer vertical, two postorbitals.

Thorax: scutal tubercle absent; acrostichals 10; dorsocentrals 5; humerals 2; prealars 1; scutellars 4; halterals 3.

Wing ( Figure 19B View Figure 19 ): cuneiform, 3.0–3.4 times longer than broad; VR 1.58–1.60; wing setation as in Figure 19B View Figure 19 .

Legs ( Figure 19C View Figure 19 ): fore tibia with 12–15 Mm long spur; mid and hind tibiae with two well separated, 8–12 Mm long tibial combs, each with 15–24 Mm long spur; tarsi without sensilla chaetica; pulvilli absent. Lengths and ratios of leg segments in Table III.

Hypopygium ( Figure 19D, E View Figure 19 ): anal tergite 54–65 Mm long, two median setae close to anal point, one lateral seta, 14–18 apical setae; transverse anal tergite band which is slightly posteriorly produced in middle, indicating T-shape; anal point ca 24 Mm long, basally broad, without crests, distally thin and pointed; base of anal point with numerous groups of strong microtrichia; small microtrichia-free areas on each side of anal point. Gonocoxite 60–66 Mm long; gonostylus 35–36 Mm long; HR 1.67–1.89. Superior volsella ( Figure 19E View Figure 19 ) oval, medially directed with three or four dorsal and three median setae on setiger, otherwise bare; digitus absent; median volsella ca 18 Mm long, medially directed, without microtrichia, with up to 42–45 Mm long, anally directed lamellae; inferior volsella 36–39 Mm long, comparatively straight, with several distal setae, dorsal surface otherwise bare.

Pupa tentatively associated (n 5 4, unless otherwise stated). Total length 1.6–1.8, 1.7 mm; abdomen 1.1–1.3, 1.3 mm long. Colour of pupal exuviae brown with somewhat darker cephalothorax and lateral margins on abdominal segments V –IX, transverse brown pigmented band posteriorly on segment VIII.

Cephalothorax ( Figure 20A–C View Figure 20 ): cephalic tubercle well-developed cones, 30 Mm long; frontal setae taeniate, 150–175, 164 Mm long; pedicel sheath tubercle absent. Frontal apotome with strong granulation ( Figure 20A View Figure 20 ). Thoracic horn 240–350, 290 Mm long, 18– 24, 21 Mm wide with numerous 6–9, 8 Mm long chaetae on distal two-thirds of horn; precorneals taeniate, 150–220, 180 Mm long, arranged in a slight triangular pattern on small tubercles; median antepronotal taeniate on obvious tubercle, ca 215 Mm long, two lateral antepronotals: one taeniate, ca 60 Mm long, one sensillum basiconicum; two pairs of fine dorsocentrals, anterior pair somewhat longer than posterior pair (27–36, 32 Mm). Large area of granulation and fine wrinkles on thorax, a few stronger granules present along median suture line ( Figure 20B View Figure 20 ). Prealar tubercle well developed, wide; nose of wing sheath strong ( Figure 20C View Figure 20 ).

Abdomen ( Figure 20D View Figure 20 ): TII with pair of oval point patches; hook row 60–78, 69 Mm wide with 31–46, 41 hooks. TIII with pair of oval point patches; TIV– VI with p -shaped point patches, patches on TV – VI often transversely divided in middle; TVI –IX with anterolateral patches of shagreen; pleurae on segment IV – V with weak shagreen. Segment II with pedes spurii B; segment IV with pedes spurii A. Segment II with 2 D, 1–2 V, 3 L setae; segment III with 3 D, 2 V, 2 L, 1 taeniate L setae; segment IV with 3 D, 3 V, 2 L, 1 taeniate L setae; segment V with 2 D, 2–3 V, 3 taeniate L setae; segment VI with 2–3 D, 3 V, 4 taeniate L setae; segment VII with 3 D, 3 V, 4 taeniate L setae; segment VIII with 1 D, 1 semi-taeniate V, 3 taeniate L setae; segment IX with 1 taeniate D seta on anal lobe, 14–16, 15 taeniate setae in anal fringe. One pair of O-setae present anteriorly on tergites II – VII and anterolaterally on sternites II – VIII. Posterolateral spur on segment VIII well developed.

Female and larva. Unknown.

Remarks

Stempellinella lamellata is quite similar to the Palaearctic S. edwardsi , the Japanese S. coronata , and S. chambiensis in the southern hemisphere, but can be separated from all these species by the above combination of diagnostic characters. The description of the pupa is based on tentatively associated pupal exuviae from Nova Friburgo, and should be treated with caution. However, their close resemblance to the pupae of S. chambiensis , only differing in the number of lateral taeniae on segment VIII, the width and the number of teeth in the hook row in segment II, and the slightly larger cephalic tubercles supports the association since the males of S. chambiensis and S. lamellata are very similar morphologically. The species has so far only been recorded from streams in Brazil and Bolivia. Although the larvae still remain unknown, they probably build small transportable cases of sand grains and organic particles as in the remainder of the species in the genus, and most probably have morphological characters similar to those of S. chambiensis (e.g. premandible with three teeth).

ZSM

Bavarian State Collection of Zoology

VI

Mykotektet, National Veterinary Institute

V

Royal British Columbia Museum - Herbarium

TV

Centro de Estratigrafia e Paleobiologia da Universidade Nova de Lisboa

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Chironomidae

Genus

Stempellinella

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