Gobiodon acicularis Harold & Winterbottom, 1995

Gobiodon acicularis Harold & Winterbottom, 1995 View in CoL : Needlespine Coralgoby

Synonyms or described as: No recorded synonyms.

Description: Gobiodon acicularis has a unique elongated first dorsal spine that produces a triangular spike or sail first dorsal fin which is present on both sexes. The head, body and tail are all dark yellow, brown or black in colour ( Figure 2 View FIGURE 2 ), with the adults of this species known to reach 40 mm in total length ( Harold and Winterbottom, 1995; Munday, Harold and Winterbottom, 1999). Juveniles of this species are white with two black longitudinal stripes running the length of the body and spots on the facial region and caudal area, resembling G. spilophthalmus ( Hing et al., 2019) .

Distribution: Gobiodon acicularis was originally described from specimens in Belau, Micronesia, collected during the mid-20 th century, but the host coral and habitat was unknown at the time of description ( Harold and Winterbottom, 1995; Munday, Harold and Winterbottom, 1999).

Habitat: Further observations have been recorded by Munday, Harold and Winterbottom (1999) of the species residing in the reef margin and lagoon areas in the corals Echinopora horrida ( Dana, 1846) , Echinopora mammiformis ( Nemenzo, 1959) and Hydnophora rigida ( Dana, 1846) . These host corals display a growth form of contorted branches and flat plates ( Veron et al., 2024). It has been identified in the Great Barrier Reef region of Australia, the Belau ( Palau) area of Micronesia and throughout South East Asia (GBIF.Org, 2024).

Status: Gobiodon acicularis population status is described as ‘Near Threatened’ as of the last IUCN assessment in 2018 ( Larson, 2020a).

Sociality: Gobiodon acicularis is one of the more social members, often found in groups as well as pairs (mean group size: 2.82, SI: 0.56) ( Hing et al., 2018; Hing, 2019).

Genetics: Recent genetic analyses have placed G. acicularis in a clade with other similarly coloured and shaped species of the genus ( Duchene et al., 2013; Herler, Bogorodsky and Suzuki, 2013; Hing et al., 2019). Such members include G. ceramensis , G. okinawae and G. citrinus from both the Pacific Ocean and Red Sea ( Harold et al., 2008; Duchene et al., 2013; Herler, Bogorodsky and Suzuki, 2013; Hing et al., 2019). The clade also includes the species G. spilophthalmus , for which recent genetic analysis indicates are more likely juveniles of the sister species G. acicularis and G. ceramensis , rather than a distinct species ( Hing et al., 2019). This clade is known for being found in host corals outside of the genus Acropora , including the family Pocilloporidae, Gray, 1840 .