Chlorotabanus Lutz, 1913

Krolow, Tiago Kütter & Henriques, Augusto Loureiro, 2010, Taxonomic revision of the New World genus Chlorotabanus Lutz, 1913 (Diptera: Tabanidae), Zootaxa 2656, pp. 1-40 : 4

Chlorotabanus Lutz, 1913

Chlorotabanus Lutz, 1913: 6 ; type-species, Tabanus mexicanus Linnaeus, 1758 (mon.); 1914: 167 (Reprint of paper of 1913); Bequaert, 1926: 234 (key and Nom. nov.); Kröber, 1930: 15 (key); 1934: 296 (catalog and Nom. nov.); Stone, 1938: 27 (diagnosis); Fairchild, 1940: 714 (key); Philip, 1947: 286 (catalog); 1952: 311 (synonym); Philip & Fairchild, 1956: 313 –324, figs. Text 1A–E, 1 (revision, key and new species); Fairchild, 1961: 437, fig. 2, 439–440 (new species); 1969: 208 (classification); 1971: 55 (catalog); Goodwin, 1973: 6 –7, figs. 1,6 (immature stages); Goodwin & Murdoch, 1974: 99 –102 (pupae, larvae, key to immature stages); Coscarón, 1976: 49, fig. 4 (terminalia illustrations); Wilkerson, 1979: 237 (new species, diagnosis, key); Fairchild, 1986: 58 (key); Coscarón & Papavero 1993: 8, 22, figs. 44–45 (illustrated manual); Fairchild & Burger, 1994: 87 (catalog); Burger, 1995: 34 (catalog); Krolow & Henriques, 2008: 270 (male description and terminalia); Coscarón & Papavero 2009a: 11, 76–77, figs. 48– 49 (Manual); Coscarón & Papavero 2009b: 67 –68 (catalog); Krolow & Henriques, 2009: 204 (new species).

Species of Chlorotabanus are nocturnal or crepuscular with occasional reports of diurnal activity. They are easily distinguished from other tabanids by the greenish color (in life), eyes glabrous, uniform reddish or yellowish-brown and the absence of a frontal callus. Specimens stored for a long time generally yellowish. Size is quite variable (7.6–17.4mm) as is the shape of the frons, which is usually somewhat convergent towards the base which is always narrower than the apex. Ocelli are absent. Antenna in females usually with a basal plate longer than or subequal to the style, without dorsal tooth, with only a slightly elevated dorsal angle. In males, basal plate reduction and stylus elongation are common, with the stylus often longer than the basal plate. Also in males, palpus is erect (porrect) and more pointed proximally, with a slight enlargement distally. In females, proximal portion of second palpomere is slightly inflated. Labella sclerotized. Glabrous basicosta, wing hyaline, often with darkened costal cell, cross-veins with or without black spots. Thorax variable in color, whitish, yellowish or orangish. Greenish legs with variable pilosity, often with black hairs at the apices of the tibiae. Greenish to yellowish abdomen with pilosity similar to thorax, except for the usually black pilosity of the last three tergites.

Color variation: While color as a taxonomic character is debated, hair and pruinosity color in Chlorotabanus may often be a tool for identification of many species and therefore should be used. Color is often quite variable and randomly distributed over the body. One possible explanation for such variability is that Chlorotabanus have green hemolymph and that influences the internal distribution of pigments which then may or may not color the various parts of the body and appendages ( Wilkerson 1979), leading to many color combinations. Another commonly seen variation is that the darkness of the last abdominal segments that may be caused by external pigments or a recent blood meal ( Wilkerson 1979). Eyes are also variable from grayish bronze to dark red, almost black, even in dry specimens.

Terminalia: Over the years, the frontal callus and antenna were considered “sacred” characters that were important in the identification of species of Tabanidae . Thus, the lack of a frontal callus and the wide variation in the types of antenna made it difficult to separate the species in the genus Chlorotabanus . On the other hand, the use of internal characters, such as male terminalia, is well used with good results for many species of Diptera . We examined several terminalia of all species with available male. Unfortunately, structures are very similar and intraspecific variability was often as great as interspecific variability. Both Coscarón (1976) and Krolow and Henriques (2008; 2009) use internal characters for C. parviceps , C. leucochlorus and C. flagellatus respectively. Krolow and Henriques (2009) in a study of C. flagellatus concluded that some externally identical individuals had more variable terminalia than when compared to other species. For these reasons, we do not use terminalia in this review.