Gopalkrishna Dattatraya Hegde

Many species reproduce by participating in explosive breeding events, where hundreds of individuals converge at specific locations for a short time period to mate. During these spectacular aggregations, many males must actively search and compete for a limited number of females. One idea is that sexual selection in explosive breeding species favors the evolution of communication strategies facilitating easy detection of males and females. As such, the emergence of dynamic sexual dichromatism, a reversible change of body coloration of one sex, might act as a visual signal promoting rapid mate recognition in dense breeding aggregations. We tested this idea in Asian Common Toads (Duttaphrynus melanostictus), an explosive breeder in which males quickly turn from brown to bright yellow for up to two days during mating. Thus, we first explored whether color differences of brown and yellow are sufficient to be perceived and distinguished by toads using a color vision model. In a set of behavioral experiments, we then tested the interactions of male toads with a yellow (resembling a breeding male) and a brown (resembling a female) 3D model toad to determine the functional significance of yellow male coloration during mating. Finally, we compared male body color, morphological parameters, and body condition of mated and non-mated males to investigate if these traits are influenced by securing a mate or female mate choice. Our results show that dynamic yellow coloration displayed by males can be easily discriminated against brown female conspecifics from a toad's point of view. During model experiments, males had twice as much physical contact with brown models and clasped them 40 times more often than yellow models. Coloration and several morphological traits did not differ between mated and non-mated males; hence, securing a mating partner was not influenced by variations in color or morphology. Our study supports the idea that dynamic sexual dichromatism repeatedly evolved as a visual signal mediating fast mate recognition in tropical and temperate anuran species solving a common problem in time-limited, dense breeding aggregations, by minimizing same-sex harassment and mismatch.

A new species of gecarcinucid freshwater crab, Ghatiana dvirupa sp. nov., is described herein from the Kali Tiger Reserve of the Uttara Kannada district, Karnataka state, India. The Kali Tiger Reserve is a protected area, which is situated in the Central Western Ghats. The new species superficially most resembles Ghatiana sanguinolenta Pati, Thackeray & Pawar, 2023, from Karnataka but can easily be distinguished mainly by its ultimate article of the male first gonopod, which is distally gently curved inwards against the gently outwardly curved distal portion of the ultimate article in the latter species. Ghatiana dvirupa sp. nov. is also compared with the remaining species of the genus from Karnataka and some morphologically related species from Maharashtra. The difference in colour in life has been noticed between males and females of G. dvirupa sp. nov.; as such the common name of the new species is proposed as “Mr. and Mrs. Ghat Crab”. Ghatiana Pati & Sharma, 2014, is now known for 13 species, all from the Western Ghats of India. Karnataka currently possesses six species of Ghatiana, and many new species are yet to be described.

A new genus and new species of gecarcinucid freshwater crab, Aradhya placida gen. et sp. nov., is recognized from the northern part of the Central Western Ghats of India. The new genus is diagnosed, and the new species from the Uttara Kannada district of Karnataka state, is described herein. The new genus most resembles Arcithelphusa Pati & Sudha Devi, 2015, Cylindrotelphusa Alcock, 1909, Rajathelphusa Raj, Kumar & Ng, 2021, and Pavizham Raj, Kumar & Ng, 2022, in having an ovate, relatively narrow and deep carapace, with the front narrow as compared to other Indian gecarcinucid genera. Aradhya gen. nov. is nevertheless separated from those genera by the characters in the carapace, epigastric and postorbital cristae, external orbital angle, cervical grooves, third maxilliped, chelipeds, male thoracic sternites/sternopleonal cavity/pleon, male second gonopod, and especially by the elongated male telson and the stouter ultimate article of the male first gonopod.

Vela bandhavya sp. nov., a new species of gecarcinucid crab is described from the Central Western Ghats, Uttara Kannada district, Karnataka state, India. The new species can be immediately distinguished from three other species of Vela Bahir & Yeo, 2007, mainly by its short male sternopleonal cavity and a relatively shorter distal article of the male first gonopod. The diagnosis of Vela is revised to accommodate the new species, and an illustrated identification key is provided for all four species. An anomalous adult male crab, with a pair of pleopods on the pleonal somite 5 in addition to the male gonopods, is also reported.