Simulium (Chirostilbia) subpallidum Lutz

HERNÁNDEZ, LUIS MIGUEL, SHELLEY, ANTHONY JOHN, DE LUNA DIAS, ANTONIO PAULINO ANDRADE & MAIA-HERZOG, MARILZA, 2007, New specific synonymies and taxonomic notes on Neotropical black flies (Diptera: Simuliidae) belonging to the subgenera Chirostilbia Enderlein, Hemicnetha Enderlein, Inaequalium Coscarón & Wygodzinsky, Psaroniocompsa Enderlein and Psilopelmia Enderlein, Zootaxa 1506 (1), pp. 1-80 : 8-10

Simulium (Chirostilbia) subpallidum Lutz

( Figs. 9–12 , 59,60 , 82 , 100 , 124–126 , 171–173 , 202–204 )

Simulium subpallidum Lutz, 1910: 247 . LECTOTYPE ♀, BRAZIL: Minas Gerais State, Benjamin Constant; 16.10 [=1910] [Without collector’s name, but probably collected by A. Lutz.] [Examined.] (IOC). New type designation.

Simulium guerreroi Ramírez Pérez, 1971: 355 . HOLOTYPE [Life stage not stated in original description.], VENEZUELA: Estado Bolívar, Ciudad Bolívar, Rio Candelaria; [Without date or collector’s name, but presumably collected by Ramírez Pérez] [Holotype said to be deposited in DERM, but location unknown- see note on Ramírez Pérez, Simuliidae collection in Materials and Methods.] [Synonymy by Ramírez Pérez et al. 1982: 83.]

Simulium guarani Coscarón & Wygodzinsky, 1972: 210 . HOLOTYPE ♀ (reared), PARAGUAY: Ayo. Moroti, 13.vii.1971 (Coscarón, S.) [MLP] [Examined.] [Synonymy by Coscarón, 1982: 73.]

Simulium acarayensis Coscarón & Wygodzinsky, 1972: 216 . HOLOTYPE ♀ (reared), PARAGUAY: Rio Acaray , 1 km S/ represa; 12.vii.1971, (Coscarón) (MLP) [Examined.] New synonymy.

Simulium subpallidum was described by Lutz (1910) from two females biting a horse near Benjamin Constant (Minas Gerais), Brazil. We have examined two females from this locality in the Lutz collection in the IOC that agree with the description given by Lutz (1910) for S. subpallidum . The label on one specimen bears the following data: “Benjamin Constant, 16.10 [=1910] and IOC number “12.653”. The specimen is in good condition and we have selected it as the lectotype and labeled it accordingly. The other female from the same locality does not have a date on the label. Consequently, we are not certain of its type status (see Material Examined). In the same paper Lutz (1910) also described pupae collected at Anhemby [now Anhembí] (Tiete River), São Paulo State, and at Lassance in Minas Gerais State and extracted adults from them that he believed to be S. subpallidum . A pupa is illustrated in his Fig. 13 that is S. spinibranchium and not S. subpallidum and this is referred to in the figure legend as S. spinibranchium (= subpallidum ?). In the following key the pupa is referred to as S. spinibranchium n.sp. (= subpallidum ?). In the paper he also referred to larvae [presumably from the same localities as the pupae], but gave no morphological diagnosis. In conclusion, Lutz provided a description of female S. subpallidum , but not of the pupae. In 1932 Pinto examined pupae that Lutz had collected from Lassance and identified these as S. subpallidum and gave a brief description. Coscarón (1982) commented on this misidentification.

A name associated with S. subpallidum is S. subviride that was recorded by Lutz & Machado (1915: 46) from specimens collected in the states of Minas Gerais and Bahía. We have examined 23 pinned females and 5 pupae identified as S. subviride in the IOC collections (see Amaral-Calvão & Maia-Herzog, 2003), which fall within the morphological variation currently known for S. subpallidum . Since no description was ever given for the name subviride under the provision of the International Code for Zoological Nomenclature (1999, articles 11, 13) it is a nomen nudum.

Several species have been regarded as synonyms of S. subpallidum and we have the following comments to make. Simulium guerreroi was described by Ramírez Pérez (1971) from specimens collected in Bolívar State, Bolívar City, Candelaria River, Venezuela. He not only described and illustrated the female of this species, but also provided illustrations of the male genitalia, pupal cocoon, gill filaments, cephalic and thoracic trichomes of the pupa, and the larval head without descriptions. In addition, he did not record which life stage he had designated as the holotype of S. guerreroi and stated that “… holotype and paratypes were deposited in the DERM and BMNH collections…”. However, no type material of S. guerreroi is deposited in the BMNH, and we have been unable to obtain specimens from DERM [see Note on Ramírez Pérez Simuliidae collection in Material and Methods]. Ramírez Pérez et al. (1982) then synonymized S. guerreroi with S. subpallidum without explanation. We have examined one pupal exuviae from Venezuela in the BMNH identified as S. guerreroi by Ramírez Pérez (see Material Examined), studied the original description and figures of this species, and compared it with numerous link-reared specimens of S. subpallidum deposited in the BMNH and IOC collections. The description of the thoracic pattern of S. guerreroi as well as the morphology of the male and female genitalia, and the pupal gill configuration from specimens identified by Ramírez Pérez from Venezuela ( Fig. 202 ) fall within the variation found in S. subpallidum . Hence we confirm the synonymy of Ramírez Pérez et al. (1982).

Simulium guarani was described by Coscarón & Wygodzinsky (1972) from several females, males, pupae and larvae collected from Ayo. Moroti in Paraguay by Coscarón. Later, Coscarón (1981) stated that S. guarani falls within the variation found for S. subpallidum and considered both species as conspecific. He also pointed out that the main differences between these two taxa relied on the structure of the gonostyle ( Fig. 2J in Coscarón & Wygodzinsky 1972; Fig. 4F in Coscarón 1982), but he assumed that the specimen used in the description of S. guarani had suffered a distortion when mounted on the slide. We have examined the female holotype of S. guarani in MLP (see Material Examined), and studied the original description of this species. The holotype is in good condition and it has been glued to a card point together with its pupal exuviae. The thoracic pattern ( Figs. 9, 10 ), the morphology of the female genitalia, and the pupal gill configuration ( Fig. 203 ) are within the variation found in S. subpallidum . We have reservations about the structure of the gonostyle of S. guarani , but in the absence of male specimens of this species we agree with Coscarón’s (1982) synonymy.

Coscarón & Wygodzinsky (1972) described S. acarayense based on females, males, pupae and larvae collected in the Rio Acaray in Paraguay. A re-description of this species was also provided in Coscarón (1982, 1991). We have examined the holotype, which is deposited in the MLP. The left side of the pinned female has been glued to a card point together with its pupal pelt, which is now missing (see Material Examined). The thorax of the holotype is slightly damaged ( Figs. 11, 12 ). We have also examined two females and one male [as paratypes] and several link-reared adults deposited in the AMNH, BMNH and IOC (see Material Examined), and have studied the original description of S. acarayense . The female and male thoracic patterns ( Figs. 11, 12 , 59, 60 ), female cibarium ( Fig. 82 ), female nudiocular area ( Fig. 100 ), female abdominal coloration, and morphology of the female ( Figs. 124–126 ) and male genitalia ( Figs. 171–173 ), the pupal gill configuration ( Fig. 204 ), and the morphology of the larval hypostomium fall within the variation of S. subpallidum . Minor differences were observed in the male gonostyle and larval hypostomium in both species, but we regard these differences as due to the orientation of the specimen on the slide, and accept both species as conspecific.

The scutal pattern of S. subpallidum is very distinctive within the subgenus Chirostilbia varying from faded orange to light grey or black over its entire distribution ( Shelley et al., 2000, 2004). These authors recognized the female of this species by the thorax with a pattern consisting of four, wide, faintly pruinose longitudinal bands? lines and the male with the gonostyle conical to sub-triangular nearly as long as the gonocoxite, and the pupal gill with eight filaments with the dorsal primary branch dividing near its base (see Figs. 2, 3, 16 , 97 in Shelley et al., 2004). However, three specimens with a six-filamented pupa collected in the state of Roraima, Brazil with adults morphologically similar to the orange form of S. subpallidum have been examined in the BMNH. The variation in the colour of the adult thoracic pattern of this species as well as in number of the pupal gill configuration might indicate the presence of a species complex. However, this still requires further investigation linking morphological variation with DNA and chromosomal studies. A full description of life stages of S. subpallidum is given in Coscarón & Wygodzinsky (1972) [as S. guarani and S. acarayensis ], Coscarón (1982, 1991) and Shelley et al. (2000). The latter authors summarized the relevant literature. A key and figures to separate this species from other taxa in Guyana has been given in Shelley et al. (2004). Simulium subpallidum is common and widespread in Guyana and throughout neighbouring Brazil, where it is found in most of the states in this country ( Gil-Azevedo& Maia-Herzog, 2004), Crosskey & Howard, 2004; Material Examined). Elsewhere, it occurs in Venezuela, Argentina and Paraguay. Pupae have been collected on vegetation in rivers 3–50 m wide, with rocky beds, in the Rupununi District ( Guyana) ( Shelley et al., 2004).

Figures

PLATE 1. FIGURES 1–16. Colour patterns of the female thorax. For each species first figure is with anterior illumination and second figure with posterior illumination. 1, 2: Thyrsopelma striginotum holotype; 3, 4: S. pillosum holotype; 5, 6: S. pillosum paratype; 7, 8: S. dekeyseri holotype; 9, 10: S. guarani holotype; 11, 12: S. acarayense holotype; 13, 14: S. mutucuna holotype; 15, 16: S. inaequale neotype.

PLATE 5. FIGURES 59–78. Colour patterns of the male thorax. For each species first figure is with anterior illumination and second figure with posterior illumination. 59, 60: S. acarayense paratype; 61, 62: S. clarki paratype; 63, 64: S. nahimi paratype (as allotype); 65, 66: S. subnigrum (Brazil); 67, 68: S. jujuyense (Argentina); 69, 70: S. auripellitum (Brazil, with silver cunae]; 71, 72: Psaroniocompsa mendozoana holotype; 73, 74: S. bonaerense paratype; 75, 76: S. minuanum paratype; 77, 78: S. sicuani paralectotype.

PLATE 6. FIGURES 79–96. Female nudiocular area. 79: Thyrsopelma striginotum holotype; 80: S. pillosum holotype; 81: S. dekeyseri paratype; 82: S. acarayense paratype; 83: Trichodagmia manicata lectotype; 84: Thyrsopelma argentata holotype; 85: S. clarki paratype; 86: S. subnigrum (Brazil); 87: Psaroniocompsa opalinifrons holotype; 88: S. jujuyense (Argentina); 89: S. auripellitum holotype; 90: Pliodasina guttata holotype; 91: S. bonaerense paratype; 92: S. minuanum paratype; 93: S. costaricensis holotye; 94: S. spinifer holotype; 95: S. hoffmani lectotype; 96: S. sicuani lectotype.

PLATE 7. FIGURES 97–114. Female cibarium. 97: Thyrsopelma striginotum holotype; 98: S. pillosum holotype; 99: S. dekeyseri paratype; 100: S. acarayense paratype; 101: Trichodagmia manicata lectotype; 102: Thyrsopelma argentata holotype; 103: S. clarki paratype; 104: S. subnigrum (Brazil); 105: Psaroniocompsa opalinifrons holotype; 106: S. jujuyense (Argentina); 107: S. auripellitum holotype; 108: Pliodasina guttata holotype; 109: S. bonaerense paratype; 110: S. minuanum paratype; 111: S. costaricensis holotye; 112: S. spinifer holotype; 113: S. hoffmani lectotype; 114: S. sicuani lectotype.

PLATE 8. FIGURES 115–126. Female genitalia (cercus and pararprocts, eighth sternite and gonopophyses). 115–117: Thyrsopelma striginotum holotype; 118–120: S. laneportoi holotype; 121–123: S. dekeyseri paratype; 124–126: S. acarayense paratype. Arrow indicate a piece of chitin (artefact) superimposed on the broken left lateral arm.

PLATE 12. FIGURES 171–182. Male genitalia (ventral plate, gonocoxite and gonostyle, paramere). 171–173: S. acarayense paratype; 174–176: S. baiense holotype; 174: hypopygium in situ; 175: Gonocoxite and gonostyle left side; 176: Gonocoxite and gonostyle right side; 177–179: S. clarki paratype; 180–182: Specimen previously identified as S. nahimi by L.M.Hernández; 181: Topotype male deposited in INPA.

PLATE 14. FIGURES 202–216. Pupal gill filaments and frontoclypeus. 202: S. guerreroi (Venezuela); 203: S. guarani holotype; S. acarayense paratype; 205–207: S. oviedoi (Venezuela); 208–210: S. rivasi (Venezuela); 211: Specimen identified as S. clarki by A.J.Shelley (Brazil); 212: S. clavibranchium syntype; 213: S. clavibranchium variation (Brazil); 214: S. mbarigui holotype; 215: Topotype identified as S. nahimi by V.P.Py-Daneil at INPA; 216: S. subnigrum (Brazil). Arrows indicate a variation on the gill filaments apically.