Simulium (Anasolen) Enderlein, 1930

Figs 3–4, 16–17, 22–23, 33–37, 50–54, 71–75, 91–94, 107–108, 114–118, 127–131, 150–151

Anasolen Enderlein, 1930: 94 (as genus). Type species: Anasolen adolffriedericianus Enderlein, 1930 [=

Simulium dentulosum Roubaud, 1915]. Xenosimulium Crosskey, 1969: 86, figs 129, 161, 200–201, 277 (as subgenus of Simulium). Type species: Simulium imerinae Roubaud, 1905 .

Diagnosis

Female

Scutum black to dark brown; scutal pattern present (Figs 3–4). Cibarium unpigmented anteromedially and unarmed. Tarsal claw with subbasal tooth shorter than a third of claw length. Hypoginial valves fine and pointed, shorter or longer than sternite VIII width, inwardly directed. Anal lobe subrectangular, shorter than the cercus base width (Figs 22–23).

Male

Ventral plate two times longer than wide or with sub-equal width and length, not notched; lateral shoulders projected or not; posteromedial process absent or present. Gonocoxite longer than wide, with base almost equal in width than gonostylus width at their point of intersection (Figs 50–54). Gonostylus cylindrical, with medial region equal in width than basal region; sub-equal or shorter than gonocoxite, with blunt apex and apical spinule (Figs 50–54). Parameres with spines of equal size, or with both distinctly large and small accessory spines.

Pupa

Cocoon aperture upward directed, separated from substratum, not corbicular (Figs 71–75). Gill much shorter than pupa body, with trunk developed, and totally free or with base enclosed by cocoon anterior margin; with 8–19 filaments arranged in different planes (tridimensional); filaments stiff, cylindrical, with acute apices of different or same color than rest of the gill; inferior branch multibranched. Thoracic trichomes simples.

Larva (last instar) Cephalic apotome spots insertion area pigmented (Figs 114–118). Postocciput extended over the cervical sclerites or not. Antenna ranging from equal or shorter, to longer than labral fan stalk, with medial antennomere annulated or not. Mandibles with preapical teeth shorter, equal, or longer than apical tooth; with two to up to five mandibular serrations of different sizes. Postgenal cleft rounded; postgenal bridge longer than hypostomal length (Figs 128–131). Hypostoma anterior margin straight; hipostomal teeth extended beyond or below hypostomal anterior margin; medial tooth longer than lateral ones or at same level; lateral serrations absent or present; paralateral teeth present or absent. Body surface mostly glabrous. Abdomen gradually expanding posteroventrally to last segments, then abruptly contracting to posterior proleg (Figs 107–108). Anal sclerite no encircling base of posterior proleg. Posterior portion of abdomen without sclerotized accessory plates. Without 1+1 ventral tubercles. Rectal papillae with three multi-branched or simple lobes.

Remarks

Simulium (Anasolen) and S. (Xenosimulium) were both recovered as monophyletic and well supported based on two and eight synapomorphies, respectively (Fig. 1, Table 2, nodes 14, 13). In S. (Xenosimulium), two of them are unique: larval antenna annulated (45 (1), Fig. 127) and larval rectal papillae with undivided lobes (62 (0)).

Both groups form a clade based on five synapomorphies (Fig. 1, Table 2, node 12), some of them unique among the Afrotropical black flies: hypoginial valves of similar shape and orientation (Figs 16–17), similar anal lobe shape (Figs 22–23), and shape of pupal gills (Figs 91–94). Therefore, we propose to subsume S. (Xenosimulium) as the Imerinae species-group (Fig. 1, node 13) (five species) in S. ( Anasolen), and treat the species already included in S. ( Anasolen) as the Dentulosum species-group (Fig. 1, node 14) (11 species). Both species-groups can be differentiated by: female hypoginial valves; male ventral plate and parameres; pupal gill morphology; larval antenna, hypostoma and rectal papillae.

Dentulosum species-group

Species

Simulium bisnovem Gibbins, 1938

S. dentulosum Roubaud, 1915

S. heptaspicae Gouteux, 1977

S. kauntzeum Gibbins, 1938

S. masabae Gibbins, 1934

S. ngabogei Fain, 1950

S. nili Gibbins, 1934

S. octospicae Gibbins, 1937

S. rhodesiense De-Meillon, 1942

S. shoae Grenier & Ovazza, 1956

S. voltae Grenier, Ovazza & Valade, 1960

Diagnosis

Female

Hypoginial valves shorter than sternite VIII width (Fig. 16).

Male

Ventral plate with sub-equal width and length; lateral shoulders present (Fig. 35) or absent (Figs 33, 36–37); posteromedial process absent. Parameres with both distinctly large and small accessory spines.

Pupa

Gill filaments with apices darkly pigmented, contrasting in color with the rest of the gill (Figs 91–92, 94).

Larva (last instar)

Postocciput extended over the cervical sclerites (Figs 115, 117–118). Antenna equal or shorter than labral fan stalk; medial antennomere not annulated. Mandibles with preapical teeth shorter (e.g., S. dentulosum, S. nili) or as long as apical tooth (e.g., S. kauntzeum, S. ngabogei); two mandibular serrations of equal or different sizes. Hypostomal (Fig. 151) teeth extended beyond hypostomal anterior margin; medial tooth distinctly longer than lateral ones; lateral serrations well-developed, sharp; paralateral teeth present. Rectal papillae with three multi-branched lobes.

Distribution

Dentulosum is distributed in the following countries of the Afrotropical Region: Angola, Burkina Faso, Cameroon, Democratic Republic of Congo, Equatorial Guinea, Eritrea, Ethiopia, Ghana, Guinea, Ivory Coast, Kenya, Lesotho, Malawi, Nigeria, Rwanda, São Tomé and Príncipe, Saudi Arabia, Sierra Leone, South Africa, Sudan, Swaziland, Tanzania, Togo, Uganda, Yemen and Zimbabwe (Adler 2020).

Imerinae species-group

Species

Simulium ambositrae Grenier & Grjebine, 1959

S. griveaudi Ovazza & Ovazza, 1970

S. imerinae Roubaud, 1905

S. iphias De-Meillon, 1951

S. neireti Roubaud, 1905

Diagnosis

Female

Hypoginial valves longer than sternite VIII width (Fig. 17).

Male

Ventral plate two times longer than wide; lateral shoulders projected (e.g., Fig. 34); posteromedial process present (e.g., S. griveaudi, S. iphias, S. neireti), cylindrical and lower or equal than ventral plate length, or absent (Fig. 34). Parameres with all spines equal in size.

Pupa

Gill filaments with apices concolorous with rest of gill (Fig. 93).

Larva (last instar)

Postocciput extended over the cervical sclerites (Fig. 116). Antenna with distal antennomere and ½ of medial antennomere surpassing labral fan stalk; medial antennomere secondarity annulated (Fig. 127). Mandibles with preapical teeth equal or longer than apical tooth; supernumerary mandibular serrations (except in S. ambositrae) of different sizes. Hypostomal (Fig. 150) teeth very reduced and extended below hypostomal anterior margin; lateral serrations blunt (e.g., S. ambositrae, S. neireti) or absent (e.g., S. griveaudi, S. imerinae, S. iphias); paralateral teeth absent. Rectal papillae without secondary lobules.

Distribution

The Imerinae group is endemic to Madagascar but S. imerinae is also recorded from the Comoro Islands (Adler 2020).