Description

SINGLE PAPER

Volume 11, Issue 3 – September 2006

Wouter Holleman: Fishes of the Helcogramma steinitzi species group (Blennioidei: Tripterygiidae) from the Indian Ocean, with descriptions of two new species, pp.  89-104

Abstract

Three species of Helcogramma from the Indian Ocean that form a monophyletic group are recognised: Helcogramma steinitzi Clark (Red Sea and Gulf of Oman), H. rosea n. sp. (Andaman Sea and Sri Lanka) and H. microstigma n. sp. (East African coast and adjacent islands). Helcogramma microstigma is distinguished from the other two species by a head profile of 67°-72° (about 60° in the other two species) and a long orbital cirrus (short and triangular in the other two species) and clusters of micromelanophores on the dorsum at the ends of the second and third dorsal fins of mature males (absent in the other two species). Helcogramma steinitzi has melanophores only on the distal half of the anal fin (in the other two species melanophores cover the entire fin) and a narrow interorbital (16.6 in head length). Helcogramma rosea has a sharper head profile of 56°-62°, similar to that of H. steinitzi, but is distinguished from it by anal fin pigmentation, a wider interorbital (about 15 in head length) and smaller size (maximum SL 33 mm cf. 47 mm for H. steinitzi). The three species in the group share a number of putative synapomorphies including very close-set first two dorsal-fin spines and densely packed micromelanophores on the membrane between these first two spines of both males and females. The close similarity of the species, their distribution, and comparisons to other tripterygiid species groups are discussed.