Proximate mechanisms responsible for random mating by size in the Himalayan toad Duttaphrynus himalayanus

Exploring the mechanisms that affect mating pattern with respect to body size has implications for understanding the evolution of sexual selection. Theory predicts that the absence of a relationship between female body size and fecundity, unbiased operational sex ratio, and a short breeding season will lead to random mating by body size in anuran amphibians. We tested these predictions in the Himalayan toad Duttaphrynus himalayanus inhabiting southeastern Tibet. Our study did not detect any correlation between female body size and number of eggs laid, nor was there a significant difference in the sex ratio of toads captured from the breeding site. In addition, the toads were reproductive for only a short period, from late April to early May (typical of an explosively breeding species). As expected, we detected a weak but not significant relationship between body size of amplexing males and females. Our results revealed no apparent size-assortative pairing in the study population of the Himalayan toad and may contribute to an increasing body of literature on mating patterns in relation to body size in animals with indeterminate growth.

Description of a new species of Rhabdias Stiles and Hassall, 1905 (Nematoda: Rhabdiasidae) from Western Himalayan foothills (Uttarakhand), India

Rhabdias garhwalensissp. nov. from the lungs ofDuttaphrynus himalayanus(Günther, 1864) collected in Kimoi Tehsil, district Tehri Garhwal (Uttarakhand), India is described and illustrated.Rhabdias garhwalensissp. nov. represents the 15th species described from the Oriental zoogeographical zone and the 9th species from India. The new species is differentiated from the closely related Oriental species in having 6 lips, cup–shaped buccal cavity with muscular striations in the posterior region and smaller esophagus to body length ratio. In addition to the new species, a second species,Cosmocercoides bufonisKarve, 1944, was found in the large intestine ofD. himalayanus.

Cosmocercoides himalayanus sp. nov. (Nematoda, Cosmocercidae) in Duttaphrynus himalayanus (Amphibia, Anura) from Dehradun (Uttarakhand), India

Cosmocercoides himalayanus sp. nov. (Nematoda, Cosmocercidae) from the large intestine of Duttaphrynus himalayanus (Amphibia, Anura) from Dehradun, India is described and illustrated. Cosmocercoides himalayanus sp. nov. represents the 21st species assigned to the genus and the 9th species from the Oriental biogeographical region. Cosmocercoides himalayanus sp. nov. differs from the previously described Oriental species in number and position of rosette papillae; it is the only species possessing 24 or more rosette papillae to have 4 postcloacal papillae. In addition, a list of species assigned to Cosmocercoides is provided; however, C. fotedari Arya, 1992 is removed from the genus and until further study is considered a species inquirenda.