A New Genus of African Caecilian (Amphibia: Gymnophiona) Marvalee H. Wake Journal of Herpetology, Vol. 21, No. 1. (Mar., 1987), Pp
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A New Genus of African Caecilian (Amphibia: Gymnophiona) Marvalee H. Wake Journal of Herpetology, Vol. 21, No. 1. (Mar., 1987), pp. 6-15. Stable URL: http://links.jstor.org/sici?sici=0022-1511%28198703%2921%3A1%3C6%3AANGOAC%3E2.0.CO%3B2-C Journal of Herpetology is currently published by Society for the Study of Amphibians and Reptiles. Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/journals/ssar.html. 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For more information regarding JSTOR, please contact [email protected]. http://www.jstor.org Sun Sep 9 14:50:13 2007 fournai of Herpetology, Vol 21, No 1, pp 6-15, 1987 Copyr~ght1987 Soaety far the Study of Amphibians and Reptiles A New Genus of African Caecilian (Amphibia: Gymnophiona) Department of Zoology and Museum of Vertebrate Zoology, Un~versltyof Cal~fornia, Berkeley, Californ~a94720, USA ABSTRACT.-A new genus, Sylvacaecilia, is proposed for the species Geotrypetes grandisonae. The species is distinctly different in a number of features of osteology, soft tissue morphology, and life history, thus warranting generic status. A species of caecilian, first collected in near nostril; splenial teeth few; fetal den- 1968 in the montane deciduous forest of tition absent; higher number of secondary southwest Ethiopia, has been considered annuli; free-living larva rather than vivip- enigmatic and distinctive with regard to arous; and different phallodeal morphol- its relationships (Taylor, 1970a, 1973; Lar- ogy. It is distinct from all other African gen et al., 1972). The species was described genera of caeciliids as well. It differs from as a member of the west African genus Herpele in having the eye in a socket, not Geotrypetes of the family Caeciliidae (Geo- covered by bone, absence of the ectopter- trypetes grandisonae Taylor, 1970~).How- ygoid, and the tentacular aperture be- ever, significant differences in morpholo- tween eve and nostril. rather than below gy and life history of G. grandisonae from the nostkl; from ~chistometo~umin having other species of Geotrypetes were noted, large frontals that meet medially, by the such as reduced number of splenial teeth, absence of an ectopterygoid, by the eye higher annular counts, the tentacle nearer socket piercing the squamosal predomi- the eye than the nostril, and a free-living nately, by the small number of splenial larval stage. teeth (S. gregorii also has few splenials, but A study of the osteology, myology, and has a higher number of primary annuli visceral anatomy of the species indicates a and the other characters identifying it as number of characters that are distinctly dif- a Schistometopum), and by presence of the ferent from those of all other Geotrypetes larval period; from ldiocranium by its larg- and other African caecilians. Therefore, the er size, skull and vertebral configuration, species warrants assignment to a new ge- smaller number of splenial teeth phallo- nus, here described as: deal morphology, and larval period rather than direct development; from Boulenge- Sylvacaecilia, new genus rula by the presence of an unroofed eye Type species: Geotrypetes grandisonae socket, splenial teeth, secondary annuli Taylor. and scales; and from Afrocaecilia by the Diagnosis: A caeciliid gymnophione of presence of the unroofed eye socket, sec- the subfamily Dermophiinae, Sylvacaecilia ondary annuli and scales. Nothing is is distinct from Geotrypetes in a number of known of reproductive modes of Herpele, features: lack of a significant parietal- Boulengerula, or Afrocaecilia. squamosal diastema; lack of toothed ecto- Referred species: Geotrypetes grandisonae pterygoids; the vomer forming the medial Taylor. border of the internal nares, rather than Etymology: From sylva, Gr., referring to the internal nares enclosed by the pala- the tropical deciduous forest habitat of tines; parietals and frontals cover the mes- these animals, and caecilia, L., in reference ethmoid; maxilla mostly overlying the to the taxon. tentacular groove; tentacular aperture mid- Range: Southwestern Ethiopia (see Lar- way between eye and nostril, rather than gen et al., 1972). NEW GENUS OF CAECILIAN 7 relative to Sylvacaecilia and to most other caecilians. Geotrypetes seraphini has diaste- Largen et al. (1972) noted that adult mata between parietals and squamosals grandisonae differ from other species of and between most of the medial distance Geotrypetes in several (largely external) an- between the frontals. The tentacular atomical features and in having aquatic groove is continuous with the eye socket larvae. They commented that "only de- and roofed only anteriorly. Further, the tailed examination of skull structure is vomers are small, excluded from the likely to clarify the generic relationships choanae, and a toothed ectopterygoid is of Geotrypetes grandisonae." Taylor, too, was present. The dermal elements, especially tentative in his inclusion of the species in dorsally and laterally, are loosely connect- Geotrypetes (1970~:853). ed and do not form the compact, rather The series described by Largen et al. and rigid skull typical of many caecilians (see one paratype of S. grandisonae were avail- Wake and Hanken, 1982). Conversely, S. able for study. One juvenile specimen (110 grandisonae has extensive dermal roofing mm TL) was cleared and stained with al- and overlap (Fig. lA, B). The orbit and cian blue for cartilage and alizarin red S tentacular channel are more restricted, for bone, and one (101 mm TL) was pre- though continuous. The mesethmoid is not pared for histological examination through exposed in the dorsal midline. A toothed frontal sections of the head and the pos- ectopterygoid is absent and the vomers terior end of the body stained with he- form the antero-medial borders of the matoxylin and eosin, Mallory's azan, and choanae, as noted in the diagnosis. Stapes picro-ponceau. The cleared and stained are large and apparent dorsally in both specimen and one other were dissected to species. examine the musculature of the head re- Hyoid Apparatus. -The cartilaginous gion. The series was X-rayed. The viscera hyoid apparati of both Sylvacaecilia and were also examined macroscopically. A Geotrypetes are similar, though the cerato- cleared and stained ontogenetic series, hyals of Sylvacaecilia are broader medially, sectioned heads, and preserved specimens and the basihyal connections to the first of Geotrypetes seraphini were available for ceratobranchials are slightly longer and examination, as were specimens of Schis- thinner (Figs. 1C and 2C). The posterior tometopum thomense (FMNH 75755), S. gre- rim of the third ceratobranchials is irreg- gorii (MCZ 20112), Herpele squalostoma ular and these elements are less dilated (FMNH 168830), Scolecomorphus uluguruen- than in Geotrypetes, but this may be due to sis (MCZ 12216), S. vittatus (MCZ 25012), incomplete growth in the late larva ex- S. kirkii (MCZ 27103), Boulengerula boulen- amined. This is also suggested by the con- geri (MCZ 25002), and Afrocaecilia taitana. dition of the sectioned specimen. (The Geotrypetes and Afrocaecilia will be Teeth.-Tooth morphology and replace- deposited in the collection of the Museum ment in fetuses and adults of G, seraphini of Vertebrate Zoology, University of Cal- was described by Wake (1976) and Wake ifornia, Berkeley.) This material allowed and Wurst (1979). The fetuses have a char- elucidation of the osteology, myology, and acteristic intra-oviducal multi-rowed den- neural and visceral anatomy, provided in- tition with spoon-shaped tooth crowns formation on ontogeny, and permitted de- which is shed near birth or shortly there- tailed comparisons of these features with after (Parker, 1936, 1956; Wake, 1976, those of other taxa. 1977a), and replaced by the adult recurved Skull.-The skull of S. grandisonae (Fig. teeth having shallow labial cusps (see lA, B) is considerably more zygokrotaphic Wake and Wurst, 1979). The fetal denti- than that of Geotrypetes, the ontogenetic tion is present in intraoviducal fetuses that series of G. seraphini being the main basis have metamorphosed (i.e., have no evi- of comparison. Dermal roofing is some- dence of gills or a spiracle, have a juvenile what reduced in Geotrypetes (Fig. 2A, B), skin, etc.), as well as newborns. The adult MARVALEE H. WAKE FIG. 1. Dorsal (A) and ventral (B) views of skull and hyoid apparatus (C) of a cleared and doubly stained 117 mm total length (TL) late larva of Sylvacaecilia grandisonae (BMNH 1976 1131). Note the more extensive dermal roofing in this larva than in the juvenile of Geotrypetes seraphini (Fig. 2). Scale bar = 1 mm. Abbrevi- ations for all figures: bs = basisphenoid, c = centrum, cbs = ceratobranchials, cc = cupular cartilage, ch = cerathyal, cr = crown, dm = depressor mandibulae, e = ectopterygoid, f = frontal, fl = flange, h = hypapoph- ysis, ha = hyoid apparatus, ih = interhyoideus, ihp = interhyoideus posterior, im = intermandibularis, ja = jaw articulation, 1 = larynx, na = neural arch, np = narial plugs, npm = nasopremaxilla, p = parietal, pa = palatine, pe = pedicel, q = quadrate, r = rib, s = squamosal, st =stapes, t = tongue, th = thymus. dentition of S. ~randisonaeis similar to that S.