REVISION OF THE CARDINALFISH SUBGENUS JAYDIA (PERCIFORMES, APOGONIDAE, APOGON)

SUMMARY

Jaydia Smith was previously considered to be a junior synonym of the genus Apogon, and its species were included in the large subgenus Nectamia. This study recognises Jaydia as a separate subgenus on the basis of a derived character set (i.e. reduced serration of preopercular edges, fourth dorsal fin longest, and the presence of light organs). These, and other synapomorphies, demonstrate that Jaydia is a monophyletic lineage in the genus Apogon. Cladistic analysis of the subgenus Jaydia, using 23 characters, shows that its 10 members fall into three distinct species groups. The trun-catus group, which also includes hungi and smithi, is the least derived, with anal light organs being its single synapo-morphy; Apogon ellioti Day is a junior synonym of truncatus Bleeker. The carinotus group, which also includes queketti and poecilopterus, is characterised by smooth preopercular and posttemporal edges, series of spots or sinuous lines on the body, and no dark spots on the peritoneum. The lineatus group, which also includes novaeguinue, striatus and striatodes n. sp., has no uroneurals, 7–11 narrow dark bars on the body, 15 pectoral rays (reversed to 16 in novueguinae), and 2–3 developed gill rakers on the upper limb of the first gill arch.

The biogeography of Jaydia, which is distributed in the Indo-west Pacific, is discussed. The truncatus group is the most widely distributed with smithi being the only member of Jaydia present east of the Pacific Plate boundary (in the Marshall Islands). The lineatus group is present in Madagascar, the Arabian Sea and from the east coast of India to the west Pacific Plate boundary, except Australia. In the carinatus group, the carinatus-queketti clade has a disjunct distribution with both species being absent from India through to and including Indonesia; carinatus is apparently absent from the area between the Philippines and northwestern Australia. A key as well as distribution maps and illustrations of all the species are provided.