Bull. nut. Hist. Mus. Land. (Zool.) 63( 1 ): 13-26 Issued 26 June 1997 



Notes on the anatomy and relationships of 

 Sundasalanx Roberts (Teleostei, Clupeidae), 

 with descriptions of four new species from 

 Borneo o r * Vv> 



DARRELL J. SIEBERT 



Department of Zoology, Natural History Museum, Cromwell Road, London, U.K. SW7 5BD 



CONTENTS 



Introduction 13 



Materials and Methods 14 



Notes on the Anatomy of Sundasalanx 14 



Colour Pattern 14 



Soft Anatomy 15 



Gut 15 



Gonads 16 



Gas Bladder and Associated Structures 16 



Laterosensory Canals 17 



Osteology 17 



Caudal Skeleton 17 



Pelvic Girdle 17 



Vertebral Column 18 



Intermusculars 18 



Dorsal- and Anal-fin Supports 18 



Jaws 18 



Gill Arches 18 



Dentition 19 



Suspensorium 19 



Lower Hyoid Arch 19 



Opercular Series 19 



Infraorbital Series 19 



Skull Roofing Bones 19 



Relationships 19 



Distinctiveness of Sundasalanx praecox 20 



Descriptions of New Species 20 



Sundasalanx malleti, sp. nov 20 



Sundasalanx mesops, sp. nov 23 



Sundasalanx megalops. sp. nov 23 



Sundasalanx platyrhynchus, sp. nov 23 



Discussion 24 



Acknowledgements 25 



References 25 



SYNOPSIS. Sundasalanx has a prootic bulla and a recessus lateralis. Thus it is a clupeiform. The degree of caudal skeleton 

 consolidation found in Sundasalanx suggests relationship to the clupeid genus Jenkinsia. Sundasalanx is unusual among known 

 miniature clupeiforms. Its somatic development is equivalent to that of late stage unmetamorphosed larvae of other clupeiforms; 

 Sundasalanx is highly progenetic. Among fishes perhaps only Schindleria attains a comparable degree of progenesis. Sundasalanx 

 is widely distributed over Southeast Asia, with considerable species diversity. Descriptions are provided for four new Bornean 

 species: S. malleti Siebert and Crimmen; S. mesops Siebert and Crimmen; S. megalops Siebert and Crimmen; and S. 

 platyrhynchus Siebert and Crimmen. 



INTRODUCTION 



land, and the other from the Kapuas River, Kalimantan Barat, 

 Indonesia, as Sundasalanx praecox and Sundasalanx microps, re- 

 spectively. Sundasalanx is now known also from peninsular Malaysia 

 Roberts (1981) described two new species of minute transparent (Roberts, 1984; Kreutzman, 1993), Thailand north of the peninsula 

 fishes, one from Khlong Falamee, Isthmus of Kra, southern Thai- (Roberts, 1984), and eastern Borneo north of the Kapuas River basin 



© The Natural History Museum, 1997 



