Trophic morphology of the coral-associated genusGobiodon(Teleostei: Gobiidae) from the Red Sea

Abstract

Trophic morphology plays a major role in niche diversification among the highly diverse fish fauna of coral reefs. It gives insight into feeding types and is useful in taxonomy, as it can be used to differentiate between species and to estimate phylogenetic relationships. The gobiid genus Gobiodon comprises obligate coral dwelling species that are widespread on Red Sea and Indo-Pacific reefs. Yet very little is known about their ecology and behaviour of feeding. In this study, viscerocranial and oral jaw morphology was investigated in seven species of Gobiodon that occur in the Red Sea. Osteological analyses were carried out on enzyme cleared and alizarin red stained specimens. Shape variation of the viscerocranium was analyzed using a landmark-based geometric morphometric method on digital scans of hand drawings and visualized in thinplate splines. Shape was determined by placing landmarks on skeletal elements in their articulated state. Morphology of the dentary and premaxilla was examined in further detail after disarticulation. A combination of landmarks and semilandmarks was applied to digital photographs of the oral jaws. It was shown that orbit size influences viscerocranial morphology by delimiting the lower jaw articulation angle. The premaxilla differs both in its extent and direction of curvature and in the structure of the articular process. Form changes in the dentary are mainly caused by variation of curvature and depth. A significant relationship between oral jaw shape and the number of anterior rows of teeth was found. Morphological diversity of selected elements is used to generate hypotheses concerning the trophic biology and niche diversification of Gobiodon. Brief dietary and in situ behavioural observations were carried out to further develop and test hypotheses.

Coral Reef Surveillance: Infrared-Sensitive Video Surveillance Technology as a New Tool for Diurnal and Nocturnal Long-Term Field Observations

“…Supplementary video 3 shows the obligate coral dwelling fish Gobiodon histrio leaving the shelter of its coral colony to catch plankton from the water column. This rare event, which was captured by the direct-recording system during sunrise, has not been documented before and provides a potentially important insight as the feeding behavior of this genus is not totally clear [ 38 , 39 ].…”

Diets of coral‐dwelling fishes of the genus Gobiodon with evidence of corallivory

“…The gut contents of each species contained a variety of items suggesting a broad generalist diet (Table I). Diet is thought to vary between species of Gobiodon depending on the morphology of their feeding apparatus (Riedlecker & Herler, 2009). Many of the dietary items observed in this study were found, however, in all species and were similarly ranked in terms of percentage abundance.…”

“…This study is the first quantitative assessment of Gobiodon diets and provides evidence that coral‐dwelling gobies ingest coral tissue. Coral‐feeding behaviour has been observed in Gobiodon citrinus (Riedlecker & Herler, 2009) and G. okinawae (P.L. Munday, pers.…”

Corals Chemically Cue Mutualistic Fishes to Remove Competing Seaweeds

“…Symbiotic gobies have a similar relationship with Acropid corals. Several gobies consume coral tissue (5 of the 19 species of Gobiodon are corallivores), but no species feeds exclusively on coral (26, 27). Most Acroporid coral colonies host at least one pair of gobiids (17), these fish remain in the same coral colony for most of their adult life, and death of host corals is commonly correlated with goby population decline (17).…”

“…Most Acroporid coral colonies host at least one pair of gobiids (17), these fish remain in the same coral colony for most of their adult life, and death of host corals is commonly correlated with goby population decline (17). Gobies consume coral tissue [they also consume copepods (26) and algae growing against the coral base (27)]. Thus, like ants on Acacia , they receive shelter and food from their host, which they protect from a damaging competitor.…”