24 
JOURNAL OF MAMMALOGY 
Notwithstanding the great specialization of its type, A onyx did not 
receive general recognition as a genus till the present century. J. E. 
Gray, in 1865 and later, recognized Aonyx as a full genus, but he com- 
bined with the Aonyx capensis group the clawless otters of southern 
Asia. More than this, he divided Aonyx, as he recognized it, into 
two groups, and wrongly assigned his restricted Aonyx to the Asiatic 
species and adopted Anahyster for the African species, the only species 
originally included in Aonyx. 
Lesson, the founder of Aonyx, proposed Leptonyx in 1842,^ for the 
clawless otters of Asia, a name unfortunately doubly preoccupied, first 
for a genus of birds (Swainson 1821) and later for a genus of seals 
(Gray 1837). Both groups are entitled to full generic acceptance, 
according to standard modern opinion as to what constitute generic 
differences among mammals. Aonyx, however, has hitherto stood for 
both groups, whenever used in either a generic or a subgeneric sense. 
While the foot structure of the clawless otters of Africa and the 
small-clawed otters of Asia is similar, the external and cranial char- 
acters, including the dentition, are widely different in the two groups. 
Yet the clawless Asiatic otters have been, and are still, referred to 
Aonyx, when not placed in Lutra, and, with one exception, all the 
figures that I have seen purporting to give the cranial and dental 
characters of Aonyx have been based on the skulls of Asiatic forms. 
Hence a non-typical and, from my viewpoint, a non-congeneric form 
not originally included in the genus has been taken to typify Aonyx, 
so far as the literature of the group is concerned.^ 
Micraonyx nom. nov. 
Leptonyx (subgenus of Lutra) Lesson, Nouv. Tableau Regne Animal, Mamm., 
1842, p. 72. Type, by tautonymy, Lutra leptonyx Horsfield = Lutra 
cinerea Illiger. 
The name Leptonyx is preoccupied by Leptonyx Swainson (1821) for 
a genus of birds, and by Leptonyx Gray (1837) for a genus of seals. 
It is here replaced by Micraonyx. 
While the external differences are by no means insignificant, those 
of the skull and teeth are such as most taxonomers consider as of high 
1 Nouv. Tableau Regne Anim., Mamm., 1842, p. 72. 
2 See, for example, the well-known figure in Flower and Lydekker’s ‘Mam- 
mals Living and Extinct,' 1891, p. 568, fig. 261, “of the palate of Lutra cinerea,'' 
reproduced from ‘Palaeontologia India.' 
