Species Description: Wake MH, Donnelly MA 2009 A new lungless caecilian (Amphbibia: Gymnophiona) from Guyana. Proc Roy Soc B: doi: 10.1098/rspb.2009.1662
Microcaecilia iwokrama can be distinguished from most other Microcaecilia by having fewer secondary annuli. From M. taylori, M. iwokrama can be distinguished based on having a range of fewer primary annuli (>114 vs. 113 – 130) and the absence of a dorsal transverse groove on the first nuchal collar. From M. dermatophaga, M. iwokrama can be distinguished by its paired nasopremaxillary bones with shorter tooth rows and fewer total teeth. Microcaecilia iwokrama was not placed in the genus, Caecilia, based on the dorsally unexposed mesethmoid, the lack of inner mandibular teeth, the lack of narial plugs, the location of the tentacle, and the presence of the keel. Microcaecilia iwokramae is not a member of Oscaecilia based on several traits above and the placement of the vomeropalatine tooth rows. The specimen can be distinguished from Parvicaecilia due to the presence of the terminal keel and long premaxillopalatine tooth rows, and from Brasilotyphlus due to the lack of a diastema between the palatine and vomerine dentition. Wake and Donnelly (2009) distinguish M. iwokramae from Luetkenotyphlus, Siphonops, Mimosiphonops, Gymnopis, and Dermophis based on combinations of the features listed above. The specimen can also be distinguished from Old World members of the family, Caeciliidae, based on combinations of these features (Wake and Donnelly 2009).
In preservative, M. iwokramae is light yellow-brown on the ventral and dorsal aspects with mottled dark pigmentation around light skin glands. The throat is cream colored. The annuli become darker posteriorly (Wake and Donnelly 2009).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
The ovaries of the holotype were approximately 10 mm long. The left ovary contained four large well-developed ova (1.2 mm diameter) and the right contained three. Several developing ova were also found in both ovaries (Wake and Donnelly 2009).
Trends and Threats
The species epithet refers to the forest in which Microcaecilia iwokramae was found (Wake and Donnelly 2009).
Microcaecilia iwokramae was originally place in a new genus, Caecilita, based on skeletal and soft tissue features (i.e. the absence of lungs, closed external nares, and open orbits) by the species authority. However, further inspection by Wilkinson et al. (2014) contradicted these findings and the species was placed consequently into the genus Microcaecilia.
The type specimen (CSBD HA 1500, Center for Biological Diversity, Univ. of Guyana) is an adult female discovered opportunistically during a survey of the vertebrate fauna in Iwokrama Forest in central Guyana (Wake and Donnelly 2009).
Microcaecilia iwokramae has a single right lung that was identified based on the well-developed pulmonary artery. The left lung and left pulmonary artery are completely missing (Wilkinson et al. 2014).
Donnelly, M. A., Chen, M. H., and Watkins, G. G. (2005). ''The Iwokrama Herpetofauna: An exploration of diversity in a Guyanan rainforest.'' Ecology and Evolution in the Tropics: a Herpetological Perspective. M. A. Donnelly, B. I. Crother, C. Guyer, M. H. Wake, and M. E. White, eds., The University of Chicago Press, Chicago.
Maddin, H. C. (2011). ''Deciphering morphological variation in the braincase of caecilian amphibians (gymnophiona).'' Journal of Morphology, 272, 850-871.
Wake, M. H. and Donnelly, M. A. (2009). ''A new lungless caecilian (Amphibia: Gymnophiona) from Guyana.'' Proceedings of the Royal Society B, published online 18 November 2009, doi: 10.1098/rspb.2009.1662.
Wilkinson, M., Kok, P.J.R., Ahmed, F., Gower, D.J. (2014). ''Caecilita Wake & Donnelly, 2010 (Amphibia: Gymnophiona) is not lungless: implications for taxonomy and for understanding the evolution of lunglessness.'' Zootaxa, 3779(3), 383-388.
Originally submitted by: Zachary R. Lewis (first posted 2009-12-29)
Edited by: Kellie Whittaker; updated by Ann T. Chang (2015-04-11)
Species Account Citation: AmphibiaWeb 2015 Microcaecilia iwokramae <https://amphibiaweb.org/species/7395> University of California, Berkeley, CA, USA. Accessed May 7, 2021.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 7 May 2021.
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