Bull. nat. Hist. Mus. Lond. (Zool.) 61(2): 111-119 



Issued 30 November 1995 



Redescription of Sudanonautes flowed (De 

 Man, 1901) (Brachyura: Potamoidea: 

 Potamonautidae) from Nigeria and Central 

 Africa 



NEIL CUMBERLIDGE_ ^ 



Department of Biology, Northern Michigan University, Marquette, Michigan 49855, USA 



CONTENTS 



Introduction Ill 



Systematic Account 112 



Sudanonautes floweri (De Man, 1901) 112 



Distribution 112 



Material 112 



Description 113 



Ecological Notes 117 



Taxonomic Remarks 117 



Acknowledgements 118 



References 118 



Synopsis. The African fresh-water crab Sudanonautes floweri (De Man, 1901) is redescribed from the male syntype 

 from Sudan (designated here the lectotype) and a large series of other specimens. The species is recognised by a 

 combination of characters of the carapace, chelipeds, mandibles, and gonopods. Sudanonautes floweri is compared 

 to related species occurring in Nigeria and Central Africa. The species is found in guinea and woodland savanna 

 from northern Nigeria to southern Sudan, in tropical rain forest from south-east Nigeria to northern Angola 

 (including Bioko), and along the Zaire river and its tributaries. Sudanonautes floweri is one of the second 

 intermediate hosts of the human lung fluke (Paragonimus) in Africa. 



INTRODUCTION 



Recent major works on the taxonomy of the fresh-water 

 crabs of Africa (Bott, 1955, 1959, 1964; Monod, 1977, 1980) 

 recognise three species of Sudanonautes Bott, 1955 - S. 

 aubryi (H. Milne Edwards, 1853), S. africanus (A. Milne 

 Edwards, 1869), and S. pelii (Herklots, 1861). Since that time 

 a number of other species in this genus have been added 

 (Cumberlidge, 1991, 1993a, b). The subject of the present 

 work, S. floweri (De Man, 1901), was formerly considered by 

 both Bott (1955) and Monod (1977, 1980) to be a subspecies 

 of 5. aubryi. Sudanonautes floweri is judged here to be a good 

 species, and is redescribed from a male syntype from Sudan. 

 Gonopod 1 of S. floweri is distinct (Fig. 2 d-f), and when 

 considered in conjunction with other characters of the cara- 

 pace and sternum (Fig. 1 a-c) and mandibles (Fig. 2 a-c), can 

 be used to identify the species unequivocally. This is impor- 

 tant, since S. floweri is one of the four species of Sudanon- 

 autes that serve as the second intermediate host of the human 

 lung fluke {Paragonimus) in Nigeria and Central Africa 

 (Voelker, et al., 1975; Voelker & Sachs, 1977; Nozais, et al., 

 1980). However, the ambiguous descriptions of S. floweri and 



5. aubryi in the literature (A. Milne Edwards, 1853; De Man, 

 1901; Bott, 1955; Monod, 1977, 1980) have led to the 

 misidentification of specimens of 5. floweri as S. aubryi by 

 parasitologists (Voelker, et al., 1975, fig. 6; Voelker & Sachs, 

 1977, fig. 4). 



The right mandible and the right first and second gonopods 

 of the type of 5 floweri were removed to illustrate these 

 structures from different angles and under magnification (Fig. 

 2 a-i). Specimens of 5. floweri from Nigeria collected by the 

 author were either dug from their burrows at the sides of 

 streams, or were trapped in fishing nets set overnight in 

 ponds. One specimen (NMU 9. IV. 1983) was caught by hand 

 under rocks in a dried river bed, immediately following the 

 temporary damming of the river by villagers. Four measure- 

 ments, carapace length, carapace width, carapace height, and 

 front width, were recorded from each specimen using digital 

 callipers. Carapace proportions were calculated according to 

 carapace length. These data were pooled and used for 

 descriptions of growth (Fig. 3 a,b). Statistical comparisons 

 between species were made between sexually mature adults 

 only (Table 1). The distribution of S. floweri described here is 

 based on the direct examination of a large number of 

 specimens from 73 different localities in 9 countries. Litera- 



)The Natural History Museum, 1995 



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