Simulium duodenicornium Pepinelli, Hamada & Trivinho­Strixino, Pepinelli & Hamada & Trivinho-Strixino, 2005

Pepinelli, Mateus, Hamada, Neusa & Trivinho-Strixino, Susana, 2005, Simulium (Thyrsopelma) duodenicornium, a new black fly species (Diptera: Simuliidae) from the Southeast Region of Brazil, Zootaxa 1040, pp. 17-29: 19-28

publication ID

http://doi.org/ 10.5281/zenodo.169824

publication LSID

lsid:zoobank.org:pub:91831C00-A062-48B1-B3E4-316DAAF2987C

persistent identifier

http://treatment.plazi.org/id/03DEBC7E-E063-FFE9-1610-FEE2FC2CF963

treatment provided by

Plazi

scientific name

Simulium duodenicornium Pepinelli, Hamada & Trivinho­Strixino
status

New Species

Simulium duodenicornium Pepinelli, Hamada & Trivinho­Strixino   New Species

( Figs. 1–48 View FIGURES 1 – 10 View FIGURES 11 – 15 View FIGURES 16 – 22 View FIGURES 23 – 30 View FIGURES 31 – 37 View FIGURE 38 View FIGURE 39 View FIGURES 40 – 48 )

Female. General coloration black. Body length 2.8 mm (n = 1); thorax lateral length 1.3 mm (n = 1); wing length 2.5 mm (n = 1), wing width 1.1 mm (n = 1).

Frons, clypeus, and occiput dark brown with silver pruinosity; fronto­ocular triangle present ( Fig. 3 View FIGURES 1 – 10 ); fronto­ocular suture absent. Antenna with silver pubescence, 0.55–0.60 mm in length; scape, pedicel, and proximal area of first flagellomere brownish yellow, remaining flagellomeres dark brown ( Fig. 4 View FIGURES 1 – 10 ). Maxillary palpus brownish yellow; sensory vesicle elongated, occupying more than 1 / 3 of length of palpomere III; palpomere V twice length of palpomere III and IV. Mandible with 12 external serrations and 34–38 internal teeth. Lacinia with 25–26 retrorse teeth. Central region of cibarium with tubercles, cibarium arms sclerotized ( Fig. 6 View FIGURES 1 – 10 ). Scutum black ( Figs. 1, 2 View FIGURES 1 – 10 ), with gray­whitish hairs distributed in groups, with central line without hairs (light source anterior). Anepisternum dark brown; katepisternum light brown. Scutellum light brown with golden hairs; postnotum black. Wing vein Sc bare, R with setae, as in male wing ( Fig. 19 View FIGURES 16 – 22 ). Foreleg with coxa, trochanter, and medial to proximal area of femur light brown; distal region and all tarsal segments dark brown ( Fig. 7 View FIGURES 1 – 10 ). Middle leg with coxa, trochanter, femur, and most of tibia light brown; tibia, basitarsus, and penultimate tarsomere with distal region dark brown; other tarsomeres dark brown ( Fig. 8 View FIGURES 1 – 10 ). Hind leg with coxa dark brown, trochanter light brown, femur, tibia and tarsomere light brown with apical region dark brown ( Fig. 9 View FIGURES 1 – 10 ); calcipala as broad as long ( Fig. 5 View FIGURES 1 – 10 ). Tarsal claw base slightly prominent ( Fig. 10 View FIGURES 1 – 10 ). Femur with filiform and spatuliform setae and tibiae with filiform setae on all legs. Tergites dark brown. Basal fringe with thin, long, golden hairs. Cercus rounded; anal lobe with internal area concave medially, forming two short projection of similar width, with anterior projection more membranous ( Fig. 13 View FIGURES 11 – 15 ); in ventral view as in Figure 11 View FIGURES 11 – 15 . Hypogynial valves subovoid, covered with microtrichia ( Figs. 11, 14 View FIGURES 11 – 15 ). Genital fork with stem long, lateral arms well developed and with large anterior processes; lateral arms forming subtriangular space ( Figs. 11, 12 View FIGURES 11 – 15 ). Spermatheca subspherical, with internal cuticular microspines ( Fig. 15 View FIGURES 11 – 15 ); spermathecal duct and area of attachment unpigmented.

Male. General body coloration black; body length 2.8 mm (n = 1); thorax lateral length 1.1 mm (n = 1). Wing length 2.4 mm (n = 1), wing width 1.2mm (n = 1).

Antenna with whitish pubescense, 0.5–0.6 mm in length; scape, pedicel, and first flagellomere light brown, remaining flagellomere dark brown, palpus dark brown, sensory vesicle small, occupying less than 1 / 5 of palpomere III; palpomere V about 2.2 times as long as palpomeres III and IV. Scutum black with golden hairs densely distributed ( Figs. 16, 17 View FIGURES 16 – 22 ), without any silver or gray pattern. Scutellum dark brown, posnotum black. Anespiternum and katepisternum dark brown. Wing venation: Sc bare, Rs with hairs, and R and C with hairs and spines ( Fig. 19 View FIGURES 16 – 22 ). Legs with same color pattern as in female, but tarsal claw differentiated, with prominent projection on base ( Fig. 18 View FIGURES 16 – 22 ). Abdominal tergites black; basal fringe with long and thin, golden hairs. Gonocoxite and gonostylus brown; gonocoxite subrectangular; gonostylus elongated with 1 or 2 acute apical spines ( Fig. 21 View FIGURES 16 – 22 ). Median sclerite rectangular with medial concavity ( Fig. 22 View FIGURES 16 – 22 ). Paramere weakly sclerotized, poorly developed; membrane on central region with spicules ( Fig. 20 View FIGURES 16 – 22 ). Ventral plate subrectangular, with anterior projection as in Figs. 23, 25, 27, 29 View FIGURES 23 – 30 ; anterior projection enlarged distally and covered with setae.

Pupae ( Figs. 31–39 View FIGURES 31 – 37 View FIGURE 38 View FIGURE 39 ). Body length 3.9–4.1 mm (mean = 4.0 mm, n = 5). Dorsal length of cocoon 4.0– 4.4 mm (mean = 4.1 mm, n = 5), ventral length 2.9–3.4 mm (mean = 3.2 mm, n = 5).

Cocoon boot shaped, thick and hard, without central projection ( Figs. 31, 32, 36 View FIGURES 31 – 37 ). Gills with 12 short, thick, and rigid filaments, with tips pointed and highly sclerotized, without spicules in annular arrangement ( Figs. 33, 34 View FIGURES 31 – 37 ). Frontoclypeus with 2 pairs of short, stout, and simple frontal trichomes, 1 pair of spines above frontoclypeus ( Fig. 35 View FIGURES 31 – 37 ), surrounded by small rounded tubercles. Thorax, dorsally, with 5 pairs of spiniform trichomes ( Fig. View FIGURES 31 – 37

37). Abdomen as in Figs. 38 View FIGURE 38 and 39 View FIGURE 39 . Tergite I with 1 pair of sublateral setae ( Fig. 38 View FIGURE 38 a). Tergite II with 4 pairs of stout setae, 2 pairs of thin sublateral setae, and many small tubercles especially in anterior to medial region of tergite ( Fig. 38 View FIGURE 38 b). Tergites III and IV each with 4 anteriorly directed pairs of hooks on posterior margin ( Figs. 38 View FIGURE 38 c, d). Tergites V –IX with comblike groups of fine posteriorly directed spines on anterior margin ( Fig. 38 View FIGURE 38 e). Sternites III –IX with anterior medial comblike groups of microspines ( Fig. 39 View FIGURE 39 a). Sternites V –VII with 2 pairs of stout, bifid hooks on posterior margin ( Figs. 39 View FIGURE 39 b, c, d).

Larvae (last instar) ( Figs. 40–48 View FIGURES 40 – 48 ). Length: 6.2–7.5 mm (mean = 6.9 mm, n = 5); head capsule lateral length: 0.5–0.6 mm (mean = 0.53, n = 5), dorsal width: 0.79–0.88 mm (mean = 0.82, n = 5).

General coloration grayish black (in Carnoy’s solution). Head capsule with negative pattern as in Fig. 44 View FIGURES 40 – 48 . Cervical sclerites small, eliptical, free in membrane, each with thin, elongated sclerite anteriorly ( Figs. 40, 44 View FIGURES 40 – 48 ). Postgenal cleft subtriangular, widest medially ( Figs. 41, 42 View FIGURES 40 – 48 ), with thin, dark membrane covering its entire surface ( Fig. 41 View FIGURES 40 – 48 ). Postgenal bridge 0.5 times as long as hypostoma ( Fig. 42 View FIGURES 40 – 48 ). Subesophageal ganglion not pigmented. Antenna as long as labral fan stalk; distal and proximal articles smaller than medial article (proportions of articles proximal to distal, excluding apical sensillum, 1: 2.5–2.6: 0.9) ( Fig. 45 View FIGURES 40 – 48 ). Hypostoma with pigmented anterior margin and 9 apical teeth: lateral teeth larger and more blunt than remaining teeth, 3 small median teeth, and 4 larger, blunt intermediate teeth, lateral serrations absent and 7 or 8 setae per side ( Fig. 43 View FIGURES 40 – 48 ). Labral fan with 53–59 primary rays. Body covered with ovoid setae ( Fig. 46 View FIGURES 40 – 48 ). Ventral tubercles absent. Anterodorsal arms of anal sclerite shorter in length than posteroventral arms ( Fig. 47 View FIGURES 40 – 48 ). Posterior proleg bearing approximately 178–184 rows (n = 3), with 26–31 hooks. Anal papillae with 3 branches, each with 25–27 finger­shaped lobes ( Fig. 48 View FIGURES 40 – 48 ).

Types

Holotype ( MZUSP) male (pinned), Cachoeira stream (Cahoeira dos Pretos), 22 o 57 S; 46 o 10 W, Mantiqueira mountain chain, Joanópolis County, State of São Paulo, Brazil; collectors M. Pepinelli and N. Hamada, 22 /v/ 2004.

Paratype ( MZUSP) 1 pinned female, 1 pharate male, and 1 pharate female with genitalia mounted on permanent slide; 5 larvae and 5 pupae in 80 % ethanol, same locality as holotype, collectors M. Pepinelli, R.F. Gutierrez, F.O. Roque, 22 /viii/ 2004; INPA 1 pharate male, head and thorax pinned and remainder on slide with its respective pupal exuviae, 1 pharate female, thorax pinned and remainder on slide with its pupal exuviae; 5 larvae and 5 pupae, in 80 % ethanol, same locality as holotype, collectors M. Pepinelli, R.F. Gutierrez, F.O. Roque, 22 /viii/ 2004; INPA 10 larvae and 10 pupae in 80 % ethanol, same locality as holotype, collectors N. Hamada, N.H. Fearnside, B.Ronchi­Teles, 10 /i/ 2005; INPA 10 larvae and 10 pupae in 80 % ethanol, same locality as holotype, collector N. Hamada 1 /iii/ 2005; NHM 5 larvae and 5 pupae, same locality as holotype, collector N. Hamada 1 /iii/ 2005.

Additional Material Examined

Simulium guianense   s.l.

French Guiana.

INPA ­ 1 male and its pupal exuviae on slide, Maroni River, 17 /vi/ 1999. Collectors: N. Hamada, F. Fouque; 1 pharate male and 1 pharate female on slide, Maroni River, 17 /vi/ 1999. Collectors: N. Hamada, F. Fouque.

Etymology

The name of this species is derived from duodeni (L.) = twelve each, and cornus (L.) = horn, in reference to the number and shape of the pupal gill filaments.

Taxonomic Discussion

The female of S. duodenicornium   n. sp. has a black scutum with silver setae arranged in groups ( Figs. 1, 2 View FIGURES 1 – 10 ). This pattern is similar to that of other species in the subgenus Thyrsopelma   , with the exception of S. scutistriatum Lutz   , in which the thorax is brownish red. However, the female of the new species can be distinguished from the females of the other species of Thyrsopelma   by the anal lobe ( Fig. 13 View FIGURES 11 – 15 ); this structure is similar to those of S. guianense   s.l. Wise and S. orbitale Lutz   in that it has a membranous anterior region, but in the new species the internal side of the anal lobe is concave in the medial region, forming two short projections of similar width.

The male of S. duodenicornium   can be distinguished from males of the other species in this subgenus by the shape of the genitalia and the coloration of the scutum. The new species has a black scutum, covered with golden setae, without bands ( Figs. 16, 17 View FIGURES 16 – 22 ). The other species in this subgenus have a silver thoracic pattern, with the exception of S. perplexum Shelley, Maia­Herzog, Luna Dias & Couch   , which has a scutal pattern similar to that of the female of the new species. Simulium scutistriatum   has a dark brown scutum ( Shelley et al. 1989, Coscarón, 1991).

The pupa of the new species has 12 thick gill filaments, with the apices pointed and heavily sclerotized and without spicules in annular arrangements ( Figs. 33, 34 View FIGURES 31 – 37 ). Four other species in the subgenus Thyrsopelma   have pupae with 12 gill filaments, but they can be distinguished from the new species by the following combinations of characters: S. guianense   s.l., S. perplexum   , and S. hirtipupa Lutz   have gill filaments with spicules or projections in an annular arrangement and filaments thinner than those of the new species ( Maia­Herzog et al. 1985; Shelley et al. 1989, 1997). Additionally, S. hirtipupa   has protuberances on the cocoon and a large number of trichomes on the frontoclypeus, which were not observed in the new species. Although S. scutistriatum   has 12 gill filaments, the cocoon shape is different, with the anteroventral margin more elongated and the frontoclypeus bearing several acuminate tubercles. The pupa of S. duodenicornium   has small tubercles distributed evenly on tergite II, a condition not recorded in other species in the subgenus. Shelley et al. (1997) reported one row of simple hooks on tergite V of S. guianense   s. l. pupae; however, in the specimens of S. guianense   s. l. that we examined from French Guiana, we did not observe a row of hooks on this tergite.

The larva of Simulium duodenicornium   n. sp. has an anal lobe of up to 27 lobes, whereas the other species in this subgenus with known larvae have anal lobes of 5–15 lobes. However, in S. scutistriatum   the larvae have 30 lobes. Simulium scutistriatum   larvae have an anal disc with 280–300 rows ( Coscarón 1991), whereas the new species has approximately 180 rows. Larvae of this new species have the body cuticle covered with ovoid setae that appear to be wider than those in the other species of the subgenus. However, this observation needs to be confirmed.

Bionomics

Larvae and pupae were collected in only one stream, which had a streambed of sand, small stones, and boulders. They were collected on stems, leaves, and roots of trailing vegetation, in areas where the flow was fast and highly turbulent. The stream had clear water in the first two collection periods (May and August 2004), but the water carried sediment in the last two collections (January and March 2005) due to constant rainfall. In the area where larvae and pupae were collected, the stream bank was covered with low riparian vegetation and some grass; upstream of the waterfall there were some areas of cattle pasture. In May 2004, water temperature was 15.6 °C, pH 7.3, and electrical conductivity 14 µs/cm. The altitude at the collection area was 902 m. The females of this species were not collected biting humans during the field work.

MZUSP

Museu de Zoologia da Universidade de Sao Paulo

INPA

Instituto Nacional de Pesquisas da Amazonia

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Simuliidae

Genus

Simulium