Badhawan, Akash Deep

Gupta, Pulkit

Ugemuge, Shantanu

Vashistha, Gaurav

English

Biodiversity Informatics

 REPTILES & AMPHIBIANS  •  31: e21619  •  20241Copyright is held by the authors. Articles in R&A are made available under a  Creative Commons Attribution-NonCommercial 4.0 International license.Twinning is defined as the development of two embryos in a single egg (Yntema 1970) and has been reported in turtles (Fujiwara 1964; Louro and Pereira 2009), lizards (Speer and Bayless 2000), and snakes (Manimozhi et al. 2006; Dolia 2018), as well as crocodilians. Examples of twinning in crocodilians include Alligator mississippiensis (Ferguson 1985), Caiman latirostris (Larriera and Imhoff 1994), Crocodylus acu-tus (Velasco 2010), C. intermedius (Thorbjarnarson 1989), C. johnstoni (Ferguson 1985), C. niloticus (Blomberg 1979; Ferguson 1985), C. porosus (Hibberd 1996), C. moreletii (Platt et al. 2000), C. siamensis (Platt et al. 2012), C. palustris (Sharma et al. 2020), and Gavialis gangeticus (Acharjyo and Singh 1989). Twinning in reptiles has been observed both in captivity (Acharjyo and Singh 1989; Di Marzio et al. 2023) and in nature (Sharma et al. 2020). However, few reports document twinning in wild reptilian populations, likely attributable to methods of examination, large clutch sizes, and synchronous hatching, especially in communally nesting species (Piovano et al. 2011; Di Marzio et al. 2023). Twins in an egg usually start development at the same time, but can result in hatchlings of equal or unequal sizes, or one developed and one in an embryonic phase (Hirasawa et al. 2019). In crocodiles, twinning occurs as twins, double yolks, or axial bifurcation (Ferguson 1985). One-egg twins are usually undersized compared to normal hatchlings due to the competition for resources inside the egg (Acharjyo and Singh 1989; Platt et al. 2000), which can also compromise post-hatching survival. Causes of twinning are not known but some assumed mechanisms have been reported. Low genetic variation in bottlenecked populations can result in an Twinning in a Wild Breeding Population of Gharials (Gavialis gangeticus) in IndiaShantanu Ugemuge1, Akash Deep Badhawan2, Pulkit Gupta1, and Gaurav Vashistha1,31Gharial Conservation Programme, Katerniaghat Wildlife Sanctuary, Uttar Pradesh, India2Katerniaghat Wildlife Division, Bahraich, Uttar Pradesh, India3Department of Environmental Studies, University of Delhi, Delhi 110007, India (gaurav.vashistha91@gmail.com; https://orcid.org/0000-0002-5553-0725)Figure 1. Twin Gharial (Gavialis gangeticus) hatchlings removed from the egg in which they were found; note their small size and the shared yolk sac. Photograph by Shantanu Ugemuge.Figure 2. A second incidence of twinning in the Gharial (Gavialis gange-ticus), with an undeveloped embryo still attached to the hatchling via the umbilical cord. Photograph by Shantanu Ugemuge.HTTPS://JOURNALS.KU.EDU/REPTILESANDAMPHIBIANSReptiles & Amphibians ISSN 2332-4961https://doi.org/10.17161/randa.v31i1.21619IRCF REPTILES & AMPHIBIANS  •  VOL15, NO 4  •  DEC 2008 189TABLE OF CONTENTST A B L E  O F  C O N T E N T SF E A T U R E  A R T I C L E S Chasing Bullsnakes (Pituophis catenifer sayi) in Wisconsin: On the Road to Understanding the Ecology and Conservation of the Midwest’s Giant Serpent ...................... Joshua M. Kapfer 190 The Shared History of Treeboas (Corallus grenadensis) and Humans on Grenada: A Hypothetical Excursion ............................................................................................................................Robert W. Henderson 198R E S E A R C H  A R T I C L E S The Texas Horned Lizard in Central and Western Texas .......................  Emily Henry, Jason Brewer, Krista Mougey, and Gad Perry 204 The Knight Anole (Anolis equestris) in Florida  .............................................Brian J. Camposano, Kenneth L. Krysko, Kevin M. Enge, Ellen M. Donlan, and Michael Granatosky 212C O N S E R V A T I O N  A L E R T World’s Mammals in Crisis  .............................................................................................................................................................   220 More Than Mammals  ......................................................................................................................................................................   223 The “Dow Jones Index” of Biodiversity  ...........................................................................................................................................   225H U S B A N D R Y Captive Care of the Central Netted Dragon  ....................................................................................................... Shannon Plummer 226P R O F I L E Kraig Adler: A Lifetime Promoting Herpetology  ................................................................................................ Michael L. Treglia 234C O M M E N T A R Y The Turtles Have Been Watching Me  ........................................................................................................................ Eric Gangloff 238B O O K  R E V I E W Threatened Amphibians of the World edited by S.N. Stuart, M. Hoffmann, J.S. Chanson, N.A. Cox, R. Berridge, P. Ramani, a d B.E. Young  ................................................................................................... ..........  Robert Powell 243 CONSERVATION RESEARCH REPORTS:   Summaries of Published Conservation Research Reports  .................................  245 NATURAL HISTORY RESEARCH REPORTS:   Summaries of Published Reports on Natural History .................................  247 NEWBRIEFS  ......................................................................................................................................................................................  248 EDITORIAL INFORMATION  .....................................................................................................................................................  251 FOCUS ON CONSERVATION:   A Project You Can Support  ...............................................................................................  252Front Cover. Shannon Plummer.Totat et velleseque audant mo estibus inveliquo velique rerchil erspienimus, quos accullabo. Ilibus aut dolor apicto invere pe dolum fugiatis maionsequat eumque moditia erere nonsedis ma sectiatur ma derrovitae voluptam, as quos accullabo.Back Cover. Michael KernTotat et velleseque audant mo estibus inveliquo velique rerchil erspienimus, quos accullabo. Ilibus aut dolor apicto invere pe dolum fugiatis maionsequat eumque moditia erere nonsedis ma sectia-tur ma derrovitae voluptam, asIRCFREPTILES & AMPHIBIANSC O N S E R V AT I O N  A N D  N AT U R A L  H I S T O R YUGEMUGE ET AL.  REPTILES & AMPHIBIANS  •  31: e21619  •  20242increased number of anomalies including twinning (Gautschi et al. 2002); however, females tend to be not genetically pre-disposed to produce twins (Eckert 1990). Exposure of eggs to high incubation temperatures for long durations (e.g., cli-mate change and frequent heat waves) can lead to develop-mental abnormalities in reptiles in the wild (Telemeco et al. 2013). In captivity, abnormal fluctuations in temperature and humidity, infections, and improper amounts of oxygen dur-ing incubation can increase the frequency of twinning (Frye 1991; Di Marzio et al. 2023). Exposure to some chemicals and higher concentrations of chemical contaminants can lead to an increase in developmental abnormalities (Shirose et al. 1995; Velasco 2010). Twinning also has been related to the age and size of the females (Ferguson and Joanen 1983; Tucker and Janzen 1997).Herein we report a case of twinning in a wild breeding population of the Gharial (Gavialis gangeticus) in the Girwa River, Katerniaghat Wildlife Sanctuary, Uttar Pradesh, India. On 17 June 2023, we found an unhatched egg in a nest that had been excavated by a female Gharial. The unhatched egg was opened manually, and we recovered two hatchlings. Both were alive, of approximately similar size, and were connected by an umbilical cord (Fig. 1); both were weak and thin com-pared to the other hatchlings; and the yolk sac was visibly smaller and reduced in volume compared to those in eggs housing single hatchlings. We also observed a second egg with a possible case of twinning in a separate clutch during the same breeding season when we found a developed hatchling with an undeveloped embryo attached via an umbilical cord (Fig. 2). During the 2019 nesting season, we also had encoun-tered a Gharial egg with two developed hatchlings, both of which were smaller than other hatchlings in the nest and both died within a day of their hatching and release into the water. A previous report of twinning in the Gharial (Acharjyo and Singh 1989) described two hatchlings of unequal size, the smaller of which was dead.We have been monitoring Gharial nests in Katerniaghat since 2016 and these are the only cases of twinning that we have encountered. They appear to have no substantive effect on the nesting success of the breeding population, in which annual nest numbers have ranged between 19 and 36 in the last five years with hatching success rates reaching over 90%. However, the low frequency of twinning could reflect poor detection rates as most of the females nest communally and excavate the majority of the nests on their own.Literature CitedAcharjyo, L.N. and L.A.K. Singh. 1989. Twinning abnormality in Gavialis gange-ticus (Reptilia, Crocodilia). Journal of the Bombay Natural History and Society 86: 248–250.Blomberg, G.E.D. 1979. Double-yolked eggs in the Nile Crocodile. Journal of Herpetology 13: 368–369. http://dx.doi.org/10.2307/1563339.Di Marzio, A., E. Birbele, L. Puchades, and A. Lazdiņš. 2023. A review of twin-ning in lizards and a report of Veiled Chameleon (Chamaeleo calyptratus) twin births. Herpetology Notes 16: 471–476.Dolia, J. 2018. Notes on the distribution and natural history of the King Cobra (Ophiophagus hannah Cantor 1836) in the Kumaon Hills of Uttarakhand. Herpetology Notes 11: 217–222.Eckert, K.L. 1990. Twinning in Leatherback Sea Turtle (Dermochelys coria-cea) embryos. Journal of Herpetology 24: 317–320. http://dx.doi.org/10.2307/1564404.Ferguson, M.W.J. 1985. Reproductive biology and embryology of the crocodilians, pp. 329–491. In: C. Gans, F. Billett, and P.F.A. Maderson (eds.), Biology of the Reptilia Volume 14, Development A. John Wiley & Sons, New York, New York, USA. Ferguson, M.W.J. and T. Joanen. 1983. Temperature-dependent sex determination in Alligator mississippiensis. Journal of Zoology 200: 143–177. http://dx.doi.org/10.1111/j.1469-7998.1983.tb05781.x.Frye, F.L. 1991. Biomedical and Surgical Aspects of Captive Reptile Husbandry. Krieger Publishing, Co. Inc., Malabar, Florida, USA.Fujiwara, M. 1964. Some cases of spontaneous twinning in the loggerhead turtle. Acta Herpetologica Japon 2: 7–8 (in Japanese).Gautschi, B., A. Widmer, J. Joshi, and J.C. Koella. 2002. Increased frequency of scale anomalies and loss of genetic variation in serially bottlenecked popula-tions of the dice snake, Natrix tessellata. Conservation Genetics 3: 235–245. https://doi.org/10.1023/A:1019924514465.Hibberd, E.M.A. 1996. Abnormalities in eggs, embryos, and juvenile farmed estuarine crocodiles, Crocodylus porosus, pp. 290–295. In: Crocodiles: Proceedings of the 13th Working Meeting of the Crocodile Specialist Group of the Species Survival Commission of the IUCN-The World Conservation Union convened at Santa Fe, Argentina, 11-17 May 1996. IUCN-The World Conservation Union, Gland, Switzerland.Hirasawa, T., C. Alev, and S. Kuratani. 2019. Twins at conspicuously different developmental stages in a turtle egg. Zoological Science 36: 1–4. http://dx.doi.org/10.2108/zs180107.Larriera, A. and A. Imhof. 1994. Caiman latirostris (Broad Snouted Caiman). Omphalopagus twins. 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Herpetological Natural History 7: 181–185.Sharma, S.P., S.A. Hussain, and S. Katdare. 2020. Crocodylus palustris (Mugger Crocodile). Reproduction. Herpetological Review 51: 321.Shirose, L., C. Bishop, and A. Gendron. 1995. Amphibians and Reptiles in Great Lakes Wetlands: Threats and Conservation. Great Lakes Fact Sheet, Environment Canada, Downsview, Ontario, Canada.Speer, R.J. and M.K. Bayless. 2000. The first report of mangrove monitor twins in captivity: the remarkable reproduction and disappointing result. Reptiles 8: 30–31.Telemeco, R.S., D.A. Warner, M.K. Reida, and F.J. Janzen. 2013. Extreme devel-opmental temperatures result in morphological abnormalities in painted turtles (Chrysemys picta): a climate change perspective. Integrative Zoology 8: 197–208. http://dx.doi.org/10.1111/1749-4877.12019.Thorbjarnarson, J. 1989. Ecology of the American crocodile, Crocodylus acutus, pp. 228–258. In: P. Hall and R. Bryant (eds.), Crocodiles: Their Ecology, Management, and Conservation. 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Twinning in a wild breeding population of Gharials (Gavialis gangeticus) in India

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Twinning in a wild breeding population of Gharials (Gavialis gangeticus) in India

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