Inaequalium, Coscaron & Wygodzinsky, 1984

HERNANDEZ, LUIS MIGUEL, SHELLEY, ANTHONY JOHN, DE LUNA DIAS, ANTONIO PAULINO ANDRADE & MAIA-HERZOG, MARILZA, 2007, Review of the Neotropical blackfly subgenus Chirostilbia Enderlein (Diptera: Simuliidae) based on adults and pupal morphology, Zootaxa 1649 (1), pp. 1-96 : 13-15

Key to species of Inaequalium

Several keys exist that purport to separate the females and males of all species of the Inaequalium species group. However, we were unable to reliably separate the adult life stage of this homogenous group, except to species group using the structure of the paraproct ( Figs. 120–133 ) and the gonostyle ( Figs. 168–182 ). From there on species separation is not possible because of their morphological homogeneity and so recourse has to be made to reared specimens with attention given to pupal morphology. The reader should consult the morphological descriptions and digital images of adults as an aid to species identification. The number and configuration of the pupal gill filaments is usually the most reliable taxonomic character to identify species in this subgenus. However, variation in this character has been found in several taxa making their identification difficult for non-taxonomists. Simulium lurybayae and S. parimaense are not included in the key to species because the pupa is unknown in the former species, and because of the confusion on the status of the female and pupa of the latter (see also Taxonomic discussion under each taxon).

PUPAE

1. Gill bifid or trifid, swollen, with finger-like or fine secondary filaments and usually with bulbous protrusions.............................................................................................................................................................2

– Gills with 3–6, fine or swollen filaments, without finger-like secondary filaments and no bulbous protrusions............................................................................................................................................................5

2. Gill trifid, forwardly directed from base, regular in shape with dorsal primary branch narrowing apically and sometimes with two finger-like projections. Gill covered with fine spicules ( Figs. 236–239 ) .............. ................................................................................................................................................... S. travassosi

– Gill bifid, primary branches initially orientated in dorsal and ventral planes and then forwardly directed, irregular in shape with dorsal primary branch narrowing apically with or without finger-like projections. Gill glabrous or covered with spicules and/or hairs ( Figs. 205–211 )...........................................................3

3. Gill surface glabrous. Dorsal primary branch bifurcating basally forming tapering secondary branches; upper branch bifurcating distally and lower branch bifurcating basally. Ventral primary branch short and bulbous with two short, pointed filaments apically ( Fig. 211 ) ................................................ S. souzalopesi

– Gill surface with spicules and/or hair. Dorsal and ventral primary branches short and swollen, either tapering apically or not, with pointed ends ( Figs. 205–210 )................................................................................4

4. Dorsal primary branch with small bulbous protrusion basally, one or two ventrally directed short, stout filaments beyond mid point on ventral surface and 1–4 short, stout terminal filaments. Ventral primary branch shorter with bulbous protrusion near base. Filaments covered in spicules. ( Figs. 205, 206 ) ............ ........................................................................................................................................ S. botulibranchium

– Dorsal primary branch with small bulbous protrusion at right angle from where it points forward from its basal vertical orientation; apex of primary branch with 3–4 finger-like projections. Ventral primary branch of similar form except tapering apically with no division. Filaments covered in hairs and spicules. ( Figs. 207–210 ) ............................................................................................................................... S. petropoliense

5. Gill with four filaments................................................................................................................................6

– Gill with six filaments.................................................................................................................................8

6. Gill filaments fine ( Fig. 217 ) ............................................................................................... S. margaritatum

– Gill filaments stout ( Figs. 216 , 229–234 ).....................................................................................................7

7. Gill filaments all arising from base and tapering distally ( Fig. 216 ) ............................... S. maranguapense

– Gill bifurcating basally with a further bifurcation in each of the dorsal and ventral primary branches. Bifurcation of dorsal primary branch varying in position from basal to apical; bifurcation of ventral primary branch near mid-point of gill ( Figs. 229–234 ) ..................................................................... S. rappae

8. Gill filaments lightly to strongly swollen with basal division into three primary branches, each of which bifurcates at varying distances from base ( Figs. 219–228 ) ............................................................ S. rappae

– Gill filaments narrow and dividing into primary branches basally ( Figs. 212–215, 218 , 235 )................... 9

9. Apices of filaments club-shaped and pointed ( Figs. 212 , 213 ) ....................................... S. clavibranchium

– Apices of filaments narrow and pointed ( Figs. 214, 215, 218 , 235 ) ......................................................... 10

10. Gill divided basally into three primary branches ( Fig. 215 ) ..................................................... S. inaequale

– Gill divided basally into dorsal and ventral primary branches ( Figs. 214, 218 , 235 )................................ 11

11. Dorsal primary branch thicker than ventral primary branch. Dorsal primary branch bifurcates basally into two thick secondary branches, each of which bifurcates into finer filaments at about same level in basal half of gill ( Figs. 214, 218 ) ........................................................... S. diversibranchium , S. mariavulcanoae

- Dorsal primary branch same girth as ventral primary branch. Dorsal primary branch bifurcates basally into two fine secondary branches, each of which bifurcates into finer filaments at different levels in basal half of gill ( Fig. 235 ) ................................................................................................................ S. subnigrum

Figures

PLATE 10. FIGURES 120–133. Female cercus and paraproct of: 120: S. botulibranchium; 121: S. petropoliense; 122: S. souzalopesi; 123: S. clavibranchium; 124: S. diversibranchium; 125: S. inaequale (as S. clarki paratype); 126: S. lurybayae holotype; 127: S. maranguapense (after Pessoa et al., 2005); 128: S. margaritatum; 129: S. mariavulcanoae; 130: S. parimaense (after Ramírez-Pérez et al., 1986); 131: S. rappae; 132: S. subnigrum; 133: S. travassosi.

PLATE 13. FIGURES 168–182. Male gonocoxite and gonostyle of: 168, 169: S. botulibranchium; 170: S. petropoliense; 171: S. souzalopesi paratype; 172: S. clavibranchium; 173: S. diversibranchium (as S. missionum holotype); 174: S. inaequale specimens with three, apical spines; 175: S. inaequale (as S. clarki paratype), specimen with single, apical spine; 176: S. margaritatum (modified after Pepinelli et al., 2006); 177: S. mariavulcanoae paratype; 178: S. rappae; 179: S. subnigrum, specimen with single, apical spine; 180: S. subnigrum, specimen with several, apical spines; 181: S. travassosi holotype; 182: S. travassosi. Inset, detail of the apex of gonostyle at higher magnification.

PLATE 17. FIGURES 205–212. Pupal gill filaments of: 205: S. botulibranchium lectotype (left gill); 206: S. botulibranchium (variation); 207: S. petropoliense paratype; 208–210: S. petropoliense (gill variation, Brazil, Rio de Janeiro State, Petrópolis); 211: S. souzalopesi; 212: S. clavibranchium lectotype (IOC slide no. 225).

PLATE 18. FIGURES 213– 220. Pupal gill filaments of: 213: S. clavibranchium (gill variation, Brazil, São Paulo State, S. José do Barreiro, Nascente na Fazenda S. Sebastião da Cachoeira); 214: S. diversibranchium; 215: S. inaequale specimen from Brazil, São Paulo State; 216: S. maranguapense (after Pessoa et al., 2005); 217: S. margaritatum; 218: S. mariavulcanoae; 219: S. rappae holotype; 220: S. rappae (common pattern of gill configuration). Arrows indicate different ends of the gill filaments. [Scale bar given for all figures except for figures 215 and 219].

PLATE 20. FIGURES 229–234. Pupal gill filaments of: S. rappae (gill variations):- 229–234: Brazil, Goiás State, Rio Saia Velha. Fig. 234 shows the configuration of the pupal gill filaments and anterior region of cocoon in spirit. Arrows indicate different branching, enlargement and end of the gill filaments.

PLATE 21. FIGURES 235–239. Pupal gill filaments of: 235: S. subnigrum; 236–239: S. travassosi– 236: holotype; 237: common pattern, Brazil, São Paulo State, S. José do Barreiro; 238, 239: gill variation, Brazil, São Paulo State, S. José do Barreiro. Arrows indicate different branching, enlargement and end of the gill filaments.