Acropora kenti (Brook, 1892) status revised

Madrepora kenti Brook 1892: 458; Brook 1893: 110 * plate 11* fig.B.

Acropora kenti (Brook); Wells 1954: 493.

Here removed from synonymy with Acropora tenuis (Dana* 1846) contra Veron and Wallace 1984; 279. See also Cooke et al. 2020; Mattias et al. 2022.

Specimens examined: Madrepora kenti lectotype: NHM 1892.6.8.202* Thursday Island * Torres Strait* Australia; syntype: NHM: 1892.6.8.203* Low Woody Island * GBR* Australia; MTQ: G27054* G27078* G27236* G27245* G27280* G27281* G27282* G27284* G27285* G27286* G27287* G27288* G27289* G27292* G27298* G27711* G28444* G29061* G29064* G29899* G29903* G29905* G31175* G32447* G32448* G32455* G32456* G34149* G35014* G35015* G35138* G35139* G35140* G35141* G35142* G35638* G35879* G40909* G41100* G41101* G41102* G41103* G48325* G49331* G58409* G78648 * G78750 * G78778 * G80247 * G80266* * G80256 * G80256 * G78750 * G335181, G335182 GBR; G35638* G35897* G53273* G53275* G53281* G53284* G53288* G78014; G78046* G78064* G80270 * Papua New Guinea; G27291* G28448* G35879* G60564* G63895* G80258 Coral Sea; G60131* G80251 * G80250 Lord Howe Island.

Description: Corallum horizontal or corymbose* main branches 2.0– 2.5 cm thick. Corallites large* round* appressed tubular. Radial corallites appressed tubular* crowded and prominent* with the outer part of the wall forming a rounded lip with no inner wall. Septa moderately developed* with two directive septa prominent.

Remarks: The lectotype of A. kenti (Supporting Information* Fig. S3) differs from the holotype of A. tenuis in having thicker branches that lack tertiary branching and incipient axials* and in possessing cochleariform radial corallites arranged in neat rows. Of the specimens sequenced in this study* G80266 from Great Detached Reef and G80247 from Myrmidon Reef most closely resemble the lectotype * NHM 1892.6.8.202* designated by Wallace (1999) from Thursday Island* Torres Strait. Brook’s syntype * NHM 1892.6.8.203* from Low Woody Island near Cooktown in the northern GBR is morphologically similar to the lectotype and is almost certainly the same species. Like A. tenuis * the specimens of A. kenti in our phylogeny show considerable variation in gross morphology* in terms of both branch thickness and the neatness of the radial corallites. Two colonies collected adjacent to each other at Myrmidon Reef* GBR* and sequenced in the present series* G80247 and G78778* demonstrate the range of variation in the length and neatness of the radial corallites. Specimens also show variation in branch thickness within and between colonies* some of which might be attributable to environmental factors* such as wave exposure. Despite morphological variability within the species* molecular data clearly demonstrate that A. kenti (Brook* 1892) is distinct from A. tenuis (Dana* 1846); therefore* we formally resurrect the former species. Consequently* the species commonly referred to as A. tenuis on the GBR and elsewhere in eastern Australia (sensu Veron and Wallace 1984)* including the genome published as A. tenuis from the GBR (Cooke et al. 2020) is A. kenti. Unlike many published genomes* images were taken of the live colonies from Orpheus Island* GBR* that provided the material for the A. kenti genome. Voucher specimens from these colonies were also deposited in the collection of the Queensland Museum (G335181 and G335182)* and the morphology of the specimens closely matches the A. kenti lectotype. Based on the specimens examined here* the geographical range of A. kenti extends from Lord Howe Island north along the GBR to the Bismarck Sea and east to the Coral Sea (Supporting Information* Fig. S6).