Gambaryan P.P., Zherebtsova O.V. 2014. Short muscles of the hand and foot in Laonastes aenigmamus (Rodentia: Diatomyidae) and some other rock-dwellers // Russian J. Theriol. Vol.13. No.2: 83–95 [in English].
Petr P. Gambaryan [gambarpp@yandex.ru], Zoological Institute of the Russian Academy of Sciences. Universitetskaya emb. 1, Saint Petersburg 199034, Russia;
Olga V. Zherebtsova [hedgol@yandex.ru], Zoological Institute of the Russian Academy of Sciences. Universitetskaya emb. 1, Saint Petersburg 199034, Russia.
ABSTRACT. The short muscles of the hand and foot in the relict rock rat Laonastes aenigmamus Jenkins et al., 2005 (Rodentia: Diatomyidae) were studied for the first time. Some other rock-dwellers, Ctenodactylus gundi, Chinchilla lanigera, Ochotona macrotis, as well as Ochotona dauurica, inhabiting the plain landscapes, were also included in the morphological analysis for comparative purposes. In spite of the different localities of pikas, the structure of the short muscles of the hand and foot in both species of Ochotona is practically identical. At the same time the pikas differ substantially from the investigated rodents by a number of features of the short muscles: by the absence of the mm. palmaris brevis and add. digiti secundi in the hand and m. abd. metatarsi V in the foot; by the absence of the typical mm. lumbricales in the hand and the whole absence of these muscles in the foot; by the presence only one belly of the m. abd. digiti quinti in the hand instead of two bellies in rodents. In all studied forms, the structure of the m. add. digiti quinti in the hand and the mm. interossei both in the hand and foot, are characterized by a great similarity. Among the three investigated rodents, the most essential differences of the short muscles are connected with the reduction of the first fingers in the hand and foot in Ctenodactylus and Chinchilla. It was indicated that in Laonastes the state of the mm. lumbricales is evidently the most primitive.
KEY WORDS: Chinchilla, Ctenodactylus, Laonastes, Ochotona, short muscles of the hand and foot.