Hippocampus subelongatus, Castelnau 1873

Sara A. Lourie, Riley A. Pollom & Sarah J. Foster, 2016, A global revision of the Seahorses Hippocampus Rafinesque 1810 (Actinopterygii: Syngnathiformes): Taxonomy and biogeography with recommendations for further research, Zootaxa 4146 (1), pp. 1-66 : 41

H. subelongatus Castelnau 1873

English common names. West Australian Seahorse, tiger snout seahorse. Synonyms. H. elongatus Castelnau 1873 .

Paratypes: MNHN A-4535, MNHN A-4536, MNHN A-4552 (according to Kuiter 2001) MNHN A-4535 is probably the holotype of H. subelongatus , and A-4536 is probably the holotype of H. elongatus ).

Type locality. Swan River , Western Australia.

Distribution. Australia (southwest).

Notes. Meristic data largely overlap between H. subelongatus and H. angustus (Appendix B). Genetic divergence between H. subelongatus from Rockingham and H. angustus from Cape Bossut is 1.99% (652bp, CO1) ( Harasti 2014), which is just about at the cut-off that we set for species distinctions for this revision. However the same specimen from Rockingham had an identical haplotype to a specimen of H. angustus from Denham, Shark Bay (BOLD 2016). Further investigation is warranted. In the meantime we continue to recognize H. subelongatus as a species separate from H. angustus . In support of this decision, H. subelongatus specimens do have distinctive, very tall and rounded coronets, and are not at all spiny, unlike their northern congeners that are distinctly spiny.