REDESCRIPTION OF THE CHINESE WHITE DOLPHIN 
Table 3 The range (and average number) of teeth counted from Hong 
Kong Sousa chinensis 

Left Right 
Upper 32-36 (33.6) 32-35 (33.6) 
Lower 28-34 (31.5) 27-33 (31.1) 

the other eight Hong Kong specimens lie within a discrete range. 
The greatest variation is seen between length measurements of the 
skull, i.e. condylobasal (450-526 mm), rostral (257-325 mm), 
upper tooth row (205.5—284 mm), ramus (397-457 mm) and sym- 
physis (82.5-258 mm). The physical maturity of the holotype is 
reflected in its location at the top of each of these length values (Fig. 
7a). Least variation is seen between the width dimensions of the 
skulls, i.e., parietal (137.4-171 mm), rostral (99.2-119 mm), mid- 
rostral (47.8—62 mm), mandibular fossae (119.4—-130.9 mm) and the 
lower tooth row length (247-279 mm) (Fig. 7b). 

DISCUSSION 
The ages of nine stranded specimens of Sousa chinensis examined 
from Hong Kong waters were determined to lie between 4 and 14 
years. It is clear from the original description that the holotype was 
physically mature whereas no specimen obtained from Hong Kong 
was. This is reflected in the comparison of skeletal characters where 
the holotype is consistently the largest in terms of skull length 
measurements. The greater ossification of the scapula also is indica- 
tive of the holotype’s greater age. The measurements obtained for 
the neotype appear to be typical for Hong Kong waters, although the 
sample size is currently limited. Those measurements available for 
the holotype are, however, within the ranges obtained for Hong 
Kong specimens. The difference between vertebral counts of the 
holotype and neotype is small and such variation in other delphinids 
appears typical (Perrin, 1975). It is not known if the holotype was 
typical of the population present in Xiamen waters at the time it was 
collected (1870) and, indeed, as both Hong Kong and Xiamen 
coastal areas have been extensively developed, any adaptive changes 
that both populations of Sousa chinensis may have undergone since 
the 17" century cannot be gauged. In addition, the latest review of 
the genus (Ross et al., 1996) observes that osteological form is 
similar across its global range, with any slight differences being 
environmental rather than genetic. 
The uncertainty that prevails over the taxonomy of the genus 
Sousa can only be dispelled through the continued investigation and 
comparison of specimens from throughout its range. As the holotype 
has been destroyed, the designation of a neotype is required so that 
such comparative studies can be conducted in relation to a defined 
type and, thus, the taxonomy and life history traits of the genus 
resolved. In addition, the herein designated neotype was obtained 
from the area in which the species was originally identified (Osbeck, 
1765) and the same geographic region that the holotype was col- 
lected from (Flower, 1870). The meristic data of the neotype are 
neither significantly different from what is known of the original 
description of a Sousa chinensis skeleton (Flower 1870) nor the 
sample of other stranded specimens measured from Hong Kong 
waters. The specimen described herein, therefore, fulfils the criteria 
as laid out by the International Code of Zoological Nomenclature for 
designation as a neotype and, as such, has now been lodged in the 

85 
vertebrate collection of the Natural History Museum, London 
(Accession No. ZD 1999.360). 
ACKNOWLEDGEMENTS. The study of Hong Kong stranded marine mam- 
mals was funded by the Agriculture, Fisheries and Conservation Department 
(AFCD) of the Government of the Hong Kong Special Administrative 
Region. A special acknowledgement is made to pathologist Dr. L. Simms 
(AFCD) for his expertise and use of post mortem facilities. Mr. K.C. Choi and 
the staff of the licensing division of AFCD are gratefully acknowledged for 
their assistance in processing the CITES export permit. Many thanks also to 
Dr. G. Ross, Environment Australia, who freely gave of his expertise and 
greatly assisted in the taxonomic procedures and interpretations presented in 
this paper. The author also wishes to thank Prof. Brian Morton, Director, The 
Swire Institute of Marine Science, The University of Hong Kong, for his 
support and encouragement for this and other studies of Sousa chinensis 
conducted at the institute. 
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