Marques, Otavio A. V.

Sazima, Ivan

Phyllomedusa Journal of Herpetology

English

Cadernos Espinosanos (E-Journal)

		The neotropical colubrid snakes of thegenus Chironius include 20 species that dwellmainly in rainforests of Central and SouthAmerica (Dixon et al. 1993). These medium tolarge snakes are diurnal, arboreal to terrestrial,and feed upon frogs (Dixon et al. 1993, Sazimaand Haddad 1992, Marques et al. 2001). Severalspecies are arboreal and their ground color aregreen (e.g. Campbell and Lamar 1989, Dixon etal. 1993, Marques et al. 2001). Theirmorphology also reflect their arboreal habits asthese snakes have large eyes, slender bodies, andlong tails (Dixon et al. 1993, Marques 1998).Ontogenetic color changes are commonwithin the genus, juveniles sometimes differingmarkedly from adults (Dixon et al. 1993, Mar-ques et al. 2001). Chironius flavolineatus isregarded as the only species with no ontogeneticcolor changes (Dixon et al. 1993), but a closeexamination of preserved juvenile specimensrevealed faint cross-bands in some of them(OAVM, pers. obs.). Upon examining preservedspecimens Dixon et al. (1993) note that only C.laevicollis and C. scurrulus juveniles haveOntogenetic color changes may strengthensuggestion about systematic affinities between twospecies of Chironius (Serpentes, Colubridae)Otavio A. V. Marques1 & Ivan Sazima21 Laboratório de Herpetologia, Instituto Butantan, 05535-900 São Paulo, SP, Brazil. E-mail:otaviomarques@butantan.gov.br.2 Departamento de Zoologia and Museu de História Natural, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, Brazil	&#&%	 !!"#$$%	%		uniform color, albeit different from thatpresented  by adults. Here we present thenotable color ontogenetic changes recorded inlife for these two species of Chironius and re-late these changes to their proposed systematicaffinities (Dixon et al. 1993).We examined live individuals of Chironiuslaevicollis and C. scurrulus in the field andcaptivity, photographs of live individuals, andpreserved specimens in the herpetologicalcollection of the Instituto Butantan (IB). In bothspecies the ground color of neonates andjuveniles up to 30 cm SVL is uniformly green(Figure 1A, D). In larger juveniles and adults theground color is yellowish brown (C. laevicollis)or reddish brown (C. scurrulus), the fore-bodyblack with posterior dorsal scales edged withblack or dark brown (Figure 1B, E). As thesnakes grow larger, their hind-body becomegradually darker, and in very large individualsthe ground color is black (Figure 1C, F).Recent studies on morphology and feedinghabits indicate that the extent of arborealitydiffer among Chironius species from theAtlantic forest of southeast Brazil (Marques1998, Marques and Sazima in press). Chironiuslaevicollis has a stout body, short tail and feedmostly on leptodactylids,  showing the typicallyKeywords: Serpentes, Colubridae, Chironius laevicollis, Chironius scurrulus,ontogenetic color change, systematic affinities.		Marques and SazimaFigure 1 - Ontogenetic colour changes in Chironius laevicollis (A-C) and C. scurrulus (D-F), juveniles (A and D), smalladults (B and E), and large adults (C and F). Chironius laevicollis lengths and collection numbers: (A) about300 mm TL, unregistered; (B) 1250 mm SVL, 560 mm tail length, unregistered; (C) 1435 mm SVL, 620 mmtail length, IB 57096. The same for C. scurrulus: (D) 313 mm SVL, 136 mm tail length, unregistered; (E)1030 mm SVL, 510 mm tail length, IB 65723; (F) 1160 mm SVL, 550 mm tail length; IB 65004.  JuvenileC. scurrulus photographed by M. Martins. 0 % 		terrestrial trends within the genus (Marques1998, Marques et al. 2001). Our field recordsof active adults are all on the ground (n = 8)whereas other Chironius species from theAtlantic forest use vegetation habitually or atleast more extensively (Sazima and Haddad1992, Marques and Sazima in press, pers. obs.).Of three C. laevicollis juveniles we recorded inthe field, one was in a bromeliad above theground, the other was climbing a shrub about1.5 m tall, and the third was crossing a dirtyroad. Thus, the green color of juveniles ispossibly related to their more pronouncedarboreal habits. Field data on C. scurrulus isscarce but this snake is primarily terrestrialwhen active, and uses vegetation to rest by dayand to sleep at night (Martins and Oliveira1999). We suggest that juveniles of C. scurrulusare more arboreal than the adults, similarly towhat we recorded for C. laevicollis.Dixon et al. (1993) propose that C.laevicollis and C. scurrulus are relatively youngsister species. Differentiation between these twospecies may have occurred during the lastfragmentation between Amazonian and Atlanticforest 300,000-800,000 years ago (Zamudio andGreene 2000). The similarity of colorontogenetic changes shown here, andunrecorded for any other Chironius species todate, may strengthen the sister species conceptsuggested by Dixon et al. (1993).Martins and Oliveira (1999) suggest that thegreen juveniles of C. scurrulus mimic the alsogreen, mildly venomous and aggressive colubridPhilodryas viridissimus, and a similarsuggestion may perhaps apply to the pairs C.laevicollis-P. olfersii in the northern portion andC. laevicollis-P. aestivus in the southern portionof the Atlantic forest (Marques et al. 2001).Both Philodryas species show arboreal habits(Sazima and Haddad 1992, Martins and Olivei-ra 1999, Marques et al. 2001) as do thejuveniles of the two Chironius speciescommented here.Ontogenetic colour changes and systematic affinities between two species of ChironiusAcknowledgementsWe thank H. Ferrarrezzi for valuablesuggestions on the manuscript; V. J. Germanofor expert opinion and help with theherpetological collection of the InstitutoButantan; M. Martins for the C. scurrulusjuvenile photo; CNPq and FAPESP for essentialfinancial support.ReferencesCampbell, J. A. and W. W. Lamar. 1989. The VenomousReptiles of Latin America. Ithaca, New York. CornellUniversity Press. 425 pp.Dixon, J. R., J. A. Wiest and J. M. Cei. 1993. Revision ofthe tropical snake Chironius Fitzinger (Serpentes,Colubridae). Museo Regionale di Scienze NaturaliMonografie 13: 1-279.Marques, O. A. V. 1998. Composição faunística, histórianatural e ecologia de serpentes da Mata Atlântica, naregião da Estação Ecológica Juréia-Itatins, SP.Unpublished Ph.D. Thesis. Universidade de São Pau-lo, Brazil.Marques, O.A.V. and I. Sazima. História natural dos rép-teis da Estação Ecológica Juréia-Itatins. Pp. 254-274in O. A. V. Marques and W. Duleba (eds.), EstaçãoEcológica Juréia-Itatins: Ambiente Físico, Flora eFauna. Ribeirão Preto. Holos. (in press.)Marques, O. A. V., A. Eterovic and I. Sazima. 2001. Ser-pentes da Mata Atlântica – guia ilustrado para a Ser-ra do Mar. Ribeirão Preto. Holos. 184 pp.Martins, M. and M. E. Oliveira. 1998. Natural history ofsnakes in forests of the Manaus region, CentralAmazonia, Brazil. Herpetological Natural History 6:78-150.Sazima, I. and C. F. B. Haddad, 1992. Répteis da Serrado Japi: notas sobre história natural. Pp 212-236 in H.F. Leitão-Filho and L. P. C. Morellato (orgs.), Histó-ria Natural da Serra do Japi - ecologia e preserva-ção de uma área florestal no sudeste do Brazil. Cam-pinas. Editora Unicamp.Zamudio, K. and H. W. Greene. 1997. Phylogeography ofthe bushmaster (Lachesis muta: Viperidae):implications for neotropical biogeography, systematics,and conservation. Biological Journal of the LinneanSociety 62: 421-442.

Ontogenetic color changes may strengthen suggestion about systematic affinities between two species of Chironius (Serpentes, Colubridae)

Otavio A. V. Marques

Ivan Sazima

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Ontogenetic color changes may strengthen suggestion about systematics affinities between two species of Chironius (Serpentes, Colubridae)

https://www.revistas.usp.br/phyllo/article/download/42603/46272

Ontogenetic color changes may strengthen suggestion about systematic affinities between two species of Chironius (Serpentes, Colubridae)

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