Sundasalanx mekongensis Britz & Kottelat, 1999

Family:  Ehiravidae (River sprats)
Max. size:  2.78 cm SL (male/unsexed)
Environment:  demersal; freshwater
Distribution:  Asia: Mekong basin in Laos and Thailand.
Diagnosis:  Dorsal soft rays (total): 12-15; Anal soft rays: 16-20; Vertebrae: 38-42. Differs from all except S. praecox in having vomerine tooth plates (versus missing), more maxillary teeth (30, versus 12-19), 1-3 teeth on caudal end of basibranchial 1-2 in most specimens (versus missing), a completely ringed proximal end of epibranchial 3 surrounding third efferent branchial artery (versus partially encircled), and in lacking in midventral row of melanophores (versus presence). Differs from S. malleti in lacking a basipterygium pigment ring (versus presence). Differs from S. praecox in having several (3-5) prepectoral melanophores (versus missing), more vertebrae (38-42, versus 37-38) and no palatine teeth (versus presence). Differs from all other Sundasalangidae (except S. praecox and S. malleti) in lacking a cardiac chamber pigmentation (versus presence). Also differs from all congeners in having a dermethmoid, supraorbitals, hyomandibulars, autopterotics, exoccipitals, basioccipital and ventral hypohyals (versus these bones not ossified), more gill rakers on branchial arches (10-16 on first arch [versus 2-9], 9-11 on second and third arches, 7-9 anteriorly and 6-8 posteriorly on fourth arch, 6-7 on fifth arch).
Biology:  Found mostly in large rivers with muddy bottom, turbid water and slow to moderate current. Caught by seine and push net. In all habitats where it was collected by push-net, it was only present at depths greater than 1 meter, usually at a depth immediately below those at which a slight drop in temperature could be felt. Located above the bottom, usually above a layer of 10-20 cm loose ooze.
IUCN Red List Status: Least Concern (LC); Date assessed: 17 February 2012 Ref. (130435)
Threat to humans:  harmless

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