Prosimulium kazukii, Takaoka & Saito & Adler & Baba, 2018

Takaoka, Hiroyuki, Saito, Katsumi, Adler, Peter H. & Baba, Minoru, 2018, A new species of black fly with a yellow thorax in the genus Prosimulium (Diptera: Simuliidae) in Japan, Zootaxa 4524 (4), pp. 489-495 : 490-494

Prosimulium kazukii sp. nov.

[The LSID for the new name * Prosimulium kazukii * is urn:lsid:zoobank.org:act:4B206978-6142-495D-AE8C-90ADCE67AB7F ].

Female. Body ( Fig. 1 ) 3.2 mm long. Head. Narrower than thorax. Frons and clypeus dark brown, not shiny, densely covered with yellow hairs. Frons ( Fig. 2A ) widened dorsally. Fronto-ocular area ( Fig. 2A ) narrow, directed laterally and slightly dorsally. Antenna composed of scape, pedicel and nine flagellomeres, dark brown except scape, pedicel and base of first flagellomere yellow. Maxillary palp composed of five palpomeres, proportional length of third, fourth and fifth palpomeres 1.0:0.8–0.9:1.6–1.7; third palpomere ( Fig. 2B ) not enlarged; sensory vesicle ( Fig. 2B ) of medium-length, 0.3–0.4 times as long as third palpomere, with large opening. Maxillary lacinia with 13 or 14 inner and 20 outer teeth. Mandible with 32 inner teeth and six or seven outer teeth at some distance from apex. Cibarium ( Fig. 2C ) without any processes. Thorax. Scutum orange yellow, not shiny, densely covered with yellow short hairs intermixed with yellow upright longer hairs on prescutellar area (some longer hairs dark at least basally). Scutellum yellow, with yellow short to long hairs, of which some are dark at least basally. Postnotum yellow except medial area widely light brown to medium brown and bare. Lateral surface of thorax yellow except pleural membrane and its surrounding areas partially grayish. Pleural membrane bare. Katepisternum narrower than its depth, and bare. Legs. Foreleg: coxa, trochanter and femur yellow; tibia yellow except apex light brown; tarsus dark brown; basitarsus with thick dorsal hair crest, 6.0 times as long as its greatest width. Midleg: coxa yellow except posterior surface dark brown; trochanter and femur yellow; tibia yellow except apex light brown; tarsus dark brown. Hind leg: coxa yellow, with posterior surface partially light brown; trochanter and femur yellow; tibia yellow with extreme apex light brown; tarsus dark brown; basitarsus ( Fig. 2D ) parallel-sided, inflated, 5.3 times as long as width. Calcipala ( Fig. 2D ) small and pedisulcus absent. Wing. Length 3.0 mm. Costal vein with hairs only. Subcosta fully haired. Basal portion of radius and R 1 fully haired. R 2 apically bifurcated, fully haired. Hair tuft of base of radius yellow. Basal cell well defined. Abdomen. Basal scale yellow though mottled with light brown pigments, with fringe of yellow long hairs. Dorsal surface of abdomen yellow, mottled with light brown to varying extent, although dorsum of segments 6–8 usually widely light brown to medium brown, and densely covered with yellow short hairs. Terminalia . Sternite 8 ( Fig. 2E ) wide, bare medially, and covered with 8– 10 short to long stout hairs and several short setae on each side. Ovipositor valves ( Fig. 2E ) elongate, 1.9 times as long as sternite 8, gradually tapered to round apices, and covered with microsetae, densely near bases to sparsely toward apices, together with numerous short setae; inner margins slightly concave and moderately sclerotized and darkened on basal one-third, touching each other medially, then separated apically. Genital fork ( Fig. 2F ) of inverted Y form, with slender long stem and narrow arms having angulated apices. Paraproct in ventral view ( Fig. 2G ) with ventral surface transparent and covered with dozen sensilla, and lateral and posterior surface with numerous stout hairs; paraproct in lateral view ( Fig. 2H ) medially bent posteriorly, with round apex, covered with numerous short to medium-long hairs on lateral surface, of which several hairs along posterior one-third of ventral margin somewhat stouter and longer. Cercus in lateral view ( Fig. 2H ) subrectangular, 0.46 times as long as its width, moderately covered with short to medium-long hairs. Spermatheca in lateral view ( Fig. 2I ) mushroom-like (i.e., wider than long), well sclerotized and pigmented except base at junction with its duct unpigmented; accessory tubal ducts weakly sclerotized and unpigmented, subequal to each other and to main duct.

Male (Specimen was damaged, only the following characters were observed). Body length 3.5 mm. Head. Wider than thorax. Upper eye consisting of enlarged facets in 17 vertical columns and 22 horizontal rows. Clypeus dark brown, densely covered with yellow hairs. Antenna as in female except scape and pedicel dark yellow to light brown and base of first flagellomere yellow. Thorax. Nearly as in female except scutum narrowly light brown along posterior margin. Legs. Color nearly as in female except fore and mid trochanter narrowly darkened along apical margin of inner surface, and fore tibia more widely darkened apically. Wing. Length 3.0 mm. Other characteristics including fully haired subcosta, as in female. Abdomen. Basal scale medium brown, with fringe of yellow long hairs. Dorsal surface medium brown, mottled with yellow or light brown, and densely covered with yellow hairs; ventral surface dull yellow except sternites light to medium brown.

Pupa. Body length 4.0 mm. Head. Integument ochreous, without tubercles, although with reticulated surface patterns of small mesh size, appearing tubercle-like, but not raised or only slightly raised; three slender short trichomes close together, between frons and antennal sheath, and three somewhat stout short trichomes, of which one on upper portion of face and two close together on middle of face ( Fig. 3A ). Thorax. Integument ochreous, without tubercles, although with irregular, reticulated surface pattern formed by relatively larger meshes, with eight short trichomes on each side (three somewhat stout dorsomedially, two slender anterolaterally, one slender mediolaterally, and two slender ventrolaterally), all unbranched except dorsomedial trichomes sometimes bifid ( Fig. 3B ). Gill ( Fig. 3B ) of arborescent form, with 29–38 slender short to long filaments (longest filament ca. 2 mm), arising from short basal common stalk, with round basal fenestra on ventrolateral side; filaments ochreous, irregularly with ridges and furrows, and densely covered with minute tubercles. Abdomen. Dorsally, all segments somewhat sclerotized, ochreous and densely covered with round tubercles, although those on medial portions of segments 1 and 2 only slightly raised if at all. Segment 1 with three short slender hair-like setae and one much shorter seta on each side. Segment 2 with one short slender hair-like seta, five much shorter setae, of which two or three are stout, medially and submedially, and two much shorter stout setae laterally, on each side. Segments 3 and 4 each with four hooks each bearing basal tooth ( Fig. 3C ) along posterior margin, one stout seta and one slender seta medially and one stout seta laterally on each side. Segments 5–7 each with five short setae on each side. Segment 8 with three distinct hooklets on each side ( Fig. 3D ). Segments 4–9 each with transverse row of spinecombs near anterior margin and groups of microspines on each side. Segment 9 with distinct terminal hook and two hooklets on each side ( Fig. 3D ). Ventrally, all segments somewhat sclerotized and ochreous, except segments 6 and 7 each having longitudinal membranous area medially. Segments 3–8 each densely covered with comb-like groups of minute spines medially to submedially on anterior half or two-thirds, and small round tubercles on other areas (although sparsely on segment 8). Segment 3 with five short stout setae on each side. Segments 4–7 each with two hooks ( Fig. 3E ) along posterior margin on each side (although those on segment 4 slightly smaller, and outer hooks on segments 6 and 7 located on lateral pleural membranes). Laterally, dorsal and ventral surfaces divided on each side by narrow pleural membrane on segments 2 and 9, two narrow pleural membranes on segments 3 and 4 (spaces in between somewhat sclerotized, and covered with small tubercles), and broad pleural membrane on segments 5–8. Pleural membrane of segment 8 with three or four distinct hooklets on each side ( Fig. 3D ); that of segment 9 with six distinct hooklets, of which four are much shorter than other two, on each side ( Fig. 3D ).

Cocoon. Brownish, soft, thinly and roughly woven, wall pocket shaped, usually covering abdomen of pupa, with anterior portion not well defined, and usually covered with various debris.

Type material. Holotype. Prosimulium kazukii sp. nov. Female reared from a pupa near Lake Nozoriko , Rokugou Village, Gunma Prefecture, Honshu, Japan, 22-VII-2008, by K. Saito . Paratypes. Five pharate females, same data as holotype. Other specimens. One pharate male (abdomen damaged), same data as holotype; eight females collected while attracted to a human, elevation 660 m, Shirozu , Kobaru , Taketa City , Oita Prefecture, Kyushu , Japan, 17-VI-1990, by M. Baba; four females captured while attracted to a human, elevation 2,500 m, Oonibudakehigashi , Norikura , Azumi Village, Minamiazumi District, Nagano Prefecture, 19-VII-1989, by Y. Kobayashi .

Biological note. The biting habits of the females of this species remain unknown, although they were attracted to humans. The pupae of this species were attached to grass in a small stream with water temperature of 11 ˚C, at a high elevation of 1,555 m.

Distribution. Japan (Honshu and Kyushu).

Etymology. The species name, kazukii , is in honor of Dr. Kazuki Ogata, for his great contribution to the biology and control of insects of medical and veterinary importance.

Remarks. This new species is assigned to the P. magnum species-group, as diagnosed by Adler et al. (2004, 2012), on the basis of the female spermatheca wider than long and the ovipositor valves elongated, and the pupal gill with more than 16 filaments, typically more than 20 filaments.

The female and male of this new species are characterized by yellow thoraces ( Fig. 1 ). This character distinguishes this new species from those of the other four species of the P. magnum species-group recorded in Japan: P. apoina , P. kalibaense , P. sarurense , and P. yezoense , all of which have dark brown thoraces ( Ono, 1976, 1977, 1980; Shiraki, 1935). The color of the female and male antennae of this new species differs from that of the other four species: the scape, pedicel and base of the first flagellomere are yellow or dark yellow in this new species (entirely dark brown in the other four species). In addition, the male of this new species is readily distinguished from that of P. yezoense by the yellow tibia and femur (entirely dark in S. yezoense ).

In the pupal stage, the new species is distinguished from the four other Japanese species of the P. magnum species-group by the frons and dorsal surface of the thorax without distinct tubercles, and also from one of them by the gill with 29–38 filaments ( Fig. 3B ) (46–49 filaments in P. sarurense ). It is, however, not separable by the number of gill filaments from P. apoina , P. kalibaense or P. yezoense , which have 38–40, 26–30 and 22–37 filaments, respectively ( Ono, 1977, 1980). The pupae of P. yezoense from Hokkaido have 22–26 filaments ( Ono, 1980), whereas those of P. yezoense from Kyushu and Honshu have 23–34 and 30–37 filaments, respectively ( Baba and Takaoka, 1988; Takaoka, unpublished data).

This new species is distinguished from the 14 North American species in the P. magnum species-group by having yellowish rather than dark brown thoraces in the adults ( Adler et al., 2004). Six species of the P. hirtipes group in western North America have females, and often males, with yellowish or orange thoraces. The new species, however, can be distinguished from all known members of the P. hirtipes group (characters in parentheses) in the female by the spermatheca wider than long (longer than wide) and in the pupa by the gill with 29–38 filaments (typically 16 filaments, but as many as 27 in one European species). Although male genitalia and larvae of the new species were not available for study, we predict that they have 3–7 apical spinules on each gonostylus and a gradually expanded abdomen, respectively. Other than dark brown, the most common color of the thoracic integument in adults of the Simuliidae is yellowish or orange, which is found not only in Prosimulium , but also in Helodon Enderlein , Gigantodax Enderlein , Australian Paracnephia Rubtsov , Bunyipellum Craig, Currie & Moulton , Simulium (Nevermannia) Enderlein , Simulium (Psilopelmia) Enderlein and Simulium (Simulium) Latreille. The adaptive value of thoracic color in the Simuliidae is not known.

Figures

FIGURE 1. Whole body of adult female of Prosimulium kazukii sp. nov. (lateral view).

FIGURE 2. Adult female of Prosimulium kazukii sp. nov. A, Head (front view; antenna and lower half of proboscis omitted). B, Sensory vesicle (right side; front view). C, Cibarium (front view). D, Basitarsus and second tarsomere of hind leg (left side; outer view). E, Terminalia showing eighth sternite, ovipositor valves, paraprocts and cerci (hairs on paraprocts and cerci omitted; ventral view). F, Genital fork (ventral view). G and H, Paraprocts and cerci (right side; G, ventral view; H, lateral view). I, Spermatheca. Scale bar. 0.1 mm for A and D; 0.05 mm for B and C; 0.02 mm for E–I.

FIGURE 3. Pupa of Prosimulium kazukii sp. nov. A, Head (right half; front view). B, Anterior half of thorax and gill filaments (left side; outer view). C, Hook on dorsal surface of abdominal segment 3 (lateral view). D, Abdominal segments 8 and 9 (lateral view). E, Hook on ventral surface of abdominal segment 6 (lateral view). Scale bar. 0.1 mm for A and B; 0.05 mm for D; 0.02 mm for C and E.