KENYATTA UNIVERSITY
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MORPHOLOGY, BIOACOUSTICS, AND TADPOLE CHARACTERS OF THE FROG GENUS
PTYCHADENA IN TAITA HILLS, KENYA
NG'ENDO ROSSA (M.Sc), Zoology
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There are about 20 different species of amphibians known in Taita Hills, Kenya, majority of which have
been identified up to species level. However, the taxonomic status of Ptychadenidae in these hills is poorly
understood, and needs to be established. Different sets of characters have been used in the taxonomy of
anurans worldwide, with external morphology and bioacoustics being the most widely used. Some sets of
characters may be useful in identification of some species and not others. For instance, the external
morphology of Ptychadena in eastern Africa (and elsewhere) exhibits taxonomic problems mainly because
of poor definition of characters and understanding on intraspecific variation. Larval morphological features
too are helpful in distinguishing species in many anuran species. But again our knowledge of Ptychadena
tadpoles is still scanty. Bioacoustics have been used to study Ptychadena species in western Africa, though
knowledge on vocalisation is poor in East African Ptychadena. On this basis, this study sought to establish
the taxonomic status of the Genus Ptychadena in Taita Hills, compare the results with data from other
regions and to provide a standardized species identification by definition of Operational taxonomic Units
(OTUs). Three taxonomic tools, namely adult morphology, bioacoustics and tadpole characters were utilized
for the identification to determine the Ptychadena OTUs. A total of 113 adult and 55 tadpole specimens of
Ptychadena from Taita Hills were examined for morphological characters, and their morphometrics were
taken. Analyses included a combination of external morphology, and tadpole descriptions using
standardized statistical tools such as Principal Component Analysis (PCA). For bioacoustics, recorded calls
were digitized, and different call properties measured and compared using computer software Cool Edit
2000. Adult morphometric analysis revealed that the OTU type, sex, and individual size were some factors
responsible for variation between and within OTUs 1 and 2. However, differences were more
distinguishable after morphological examination and analysis based on absence/ and or presence of
particular non morphometric character. Morphological examination of the tadpoles revealed little or no
variation in colour, oral disc structures, and labial tooth row formula and therefore could not delineate the
respective OTU types. Acoustic comparison was not possible since no acoustic data was recorded from
OTU 1. The study concludes by recommending further research on the tadpoles, which could then form a
taxonomic basis for distinguishing between OTUs
Supervisors:
Prof. C.K.P.O. Ogol
Dr. Eunice Kairu
Dr. Stefan Lotters
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School of Graduate Studies. Kenyatta University. P.O Box: 43844-00100 Nairobi, KENYA
Tel: +254 20 810901 Ext: 57530 Direct: +254 20 812086. Fax: +254 20 811575
Email: dean-graduate@ku.ac.ke