The Madagascan fauna of the genus Curtonotum Macquart, 1844 is reviewed. Type material of the seven species described by Tsacas in 1974 (C. balachowskyi, C. boeny, C. keiseri, C. pauliani, C. sakalava, C. sternithrix and C. stuckenbergi) was studied and additional material of five of these is noted, substantially increasing their known distributions. Six of the seven species described by Tsacas are endemic to Madagascar; unpublished records indicate, however, that C. pauliani, occurs in Namibia and South Africa on the African continental mainland. Six additional endemic species are described as new: C. coronaeformis sp. n., C. gladiiformis sp. n., C. griveaudi sp. n., C. irwini sp. n., C. parkeri sp. n., and C. rinhatinana sp. n. The head and thorax, frons, wing, sixth sternite and hypandrium of the male of the 13 species are illustrated for the first time, as well as the highly diagnostic male phallus, both laterally and dorsally at the junction of the basiphallus and distiphallus. A key to species based on male characters is provided, and species distributions are mapped and interpreted. The biogeographical significance of the Madagascan species is discussed. An annotated checklist of Madagascan Curtonotidae is presented, and co-ordinates used to plot maps and a list of vegetation types in which species occur are provided.
Four genera of Curtonotidae are currently known worldwide, i.e., Axinota van der Wulp, 1886, Cyrtona s.l. Séguy, 1938, Tigrisomyia Kirk-Spriggs, 2010 and Curtonotum Macquart, 1844, all of which occur in the continental Afrotropical Region; Tigrisomyia exclusively so. Curtonotum is the most speciose genus and is found in all zoogeographical regions of the world except Australasia/Oceania and Antarctica, although Klymko and Marshall (2011) point out that Curtonotum in its current broad sense is paraphyletic with respect to Axinota, and suggest restricting the name Curtonotum to a monophyletic New World group. Two genera are known to occur on Madagascar, Axinota, represented by a single species, A. kyphosis Kirk-Spriggs, 2010, of supposed Oriental origin and Curtonotum (Appendix I). Notably, the genus Cyrtona s.l., which is extremely species-rich in the continental Afrotropical Region, is apparently absent.
The Curtonotum fauna of Madagascar has remained a neglected group and nothing is currently known of their biology and immature stages. Species in the continental Afrotropical Region are known to roost in the burrows of small mammals, hollow trees and overhangs of riverbeds, etc. (e.g., Kirk-Spriggs 2008b; Meier et al. 1997; Tsacas 1977) and, at least in the case of species occurring in xeric regions, are known to develop as scavengers in the damaged egg pods of locusts and grasshoppers (Orthoptera) (Greathead 1958; Kirk-Spriggs 2008b; Meier et al. 1997). A more complete review of the known biology of the genus will be presented in Part IV of this revision.
Specimens of C. balachowskyi Tsacas from Madagascar are subject to infestations of the entomophagous fungus Laboulbenia curtonoti Rossi & Kirk-Spriggs (Ascomycota), a species with an elongated rhizoid which penetrates the host's cuticle (Rossi & KirkSpriggs 2011). An infestation of a different, undescribed Laboulbeniales species was also observed on a specimen of C. sakalava Tsacas during the course of this study, but occurred in insufficient numbers to facilitate description.
In a first attempt to deal with the taxonomy of the Madagascan species of the genus, Tsacas (1974) described and named seven endemic species and identified, but did not name, five apparent others. Tsacas' study was, however, based on only 38 specimens. These were collected by Renaud Paulian (1913–2003), then Deputy Director of the Institut Scientifique de Madagascar, and colleagues from 1956 to 1960. This was supplemented with material sampled by Raymond Decary (1891–1973) in 1922, and Alfred “Fred” Jakob Keiser-Jenny (1895–1969) and his wife collected from May to October 1958. The study also included specimens collected by Brian Roy Stuckenberg (1930–2009), during his second Madagascan expedition from November 1957 to April 1958.
All specimens studied by Tsacas (1974), including all types, were borrowed for study from the respective institutions. A few additional specimens came to light in material loaned from Tel Aviv University, Israel, Zoologische Staatssammlung, München, Germany, and the KwaZulu-Natal Museum, Pietermaritzburg, South Africa, but by far the most substantial number of specimens now available for study result from Michael E. Irwin's extensive Arthropod Survey of Madagascar's Protected Areas (1998–2009), deposited in the California Academy of Sciences, San Francisco, USA.
Tsacas (1974) illustrated the spermathecae of five named and two unnamed Madagascan species, but did not describe these structures or assess their variability. KirkSpriggs (2008a), however, assessed intra- and inter-specific variability in spermathecal form of three continental Afrotropical species in the Curtonotum cuthbertsoni complex (sensu Tsacas 1977), with obclavate spermathecae and concluded that variability was too great to allow specific differentiation. For this reason (with the notable exceptions of C. sternithrix, which has dark rings around the sockets of all thoracic setae, and C. sakalava, which is unique in having the lateral maculae of the abdominal tergites developed into a continuous band in both sexes), only the males can be identified with certainty and then only following detailed examination of the male terminalia.
As noted above, Tsacas (1974) identified, but did not name, five “species” from Madagascar (Curtonotum sp. cf. balachowskyi n. sp. species a, C. cf. balachowskyi n. sp. species b, C. sp. cf. pauliani, n. sp. species c, Curtonotum sp. d, and Curtonotum sp. e), only the first of which is represented by a male and can be reliably determined. Close examination of the male terminalia of this specimen, in direct comparison to the types, reveals its conspecificity with C. balachowskyi. As these specimens were not formally named they