Saturday, March 25, 2023

[Mollusca • 2022] Ostrea oleomargarita • Cryptic Marine Diversity in the Northern Arabian Gulf: An Integrative Approach Uncovers a New Species of Oyster (Bivalvia: Ostreidae)

Ostrea oleomargarita Oliver, Salvi & Al-Kandari,

in Salvi, Al-Kandari, Oliver, Berrilli & Garzia, 2022. 
Animal biodiversity is greatly underestimated in nontemperate marine regions, especially for intertidal benthic organisms such as oysters. Recent surveys in the northern Arabian Gulf suggest the presence of numerous unidentified species, some of which form shallow reef ecosystems while others are cryptic and found under rocks. In this study, we focused on small oysters from Kuwait, which show typical characteristics in common with the genus Ostrea except for the presence of lophine chomata that would link it to the genera Lopha, Dendostrea, and Alectryonella. Phylogenetic analyses based on mitochondrial and nuclear markers unambiguously placed the Kuwait oyster within the Ostreinae as a sister to the Japanese species Ostrea futamiensis. The hypothesis that the Kuwait oyster represents a new species was assessed with phylogenetic and species delimitation methods combined with a morphological assessment. Results corroborated the Kuwait oysters as a new species herein described as Ostrea oleomargarita Oliver, Salvi, and Al-Kandari, sp. nov. The phylogeny of the Ostreinae shows extensive disagreement between morphology-based genera and phylogenetic clades. The genus Ostrea is polyphyletic, and the form and distribution of taxonomic characters such as chomata are not as definitive as suggested in previous studies. This study, along with other recent investigations, confirmed the Arabian Gulf as a key region for discovering marine animal diversity and suggested a possible biogeographic divide between the Eastern and Western Indo-Pacific. A pattern that has been documented in a growing number of taxa and that warrants further research attention.

Ostrea oleomargarita sp. nov.
A holotype upper shell in situ with another specimen, Al Sha’ab B holotype upper shell, internal view of attached valves showing catachomata, greenish interior and brown margin [NMW.Z.2021.009.008]
C–F paratypes, variations in external sculpture and colouration, all Al Sha’ab D brown, tubercular E black and beige, foliar F Al Sha’ab site typically encrusted with Bryozoa; [NMW.Z.2021.009.010.] G Failaka, rayed, foliar [NMW.Z.2021.009.011 #7].

Ostreoidea Rafinesque, 1815
Ostreidae Rafinesque, 1815
Ostreinae Rafinesque, 1815

Ostrea Linnaeus, 1758

Generic Definition. It is commonplace to give a generic definition when describing a new species. However, the molecular data presented here suggests that Ostrea is polyphyletic and that the new species described here and its sister taxon O. futamiensis do not cluster within the clade that includes Ostrea edulis, the type species of the genus Ostrea (see Discussion). While a systematic revision of the genus Ostrea is clearly needed, we have resorted to use Ostrea in its common understanding until a much more detailed phylogeny of the Ostreinae can be presented.

Ostrea oleomargarita Oliver, Salvi, and Al-Kandari, sp. nov.  

Derivation of Name. Derived from the combination oleo from olivarius (Latin) referring to the colour olive-green and margarita from margarites (Latin) referring to the pearly lustre of the inner surfaces of the valves. Thus, to the typical olive-green lustre of the nacreous inner surface of the valves.

Daniele Salvi, Manal Al-Kandari, P. Graham Oliver, Emanuele Berrilli,, and Matteo Garzia. 2022. Cryptic Marine Diversity in the Northern Arabian Gulf: An Integrative Approach Uncovers a New Species of Oyster (Bivalvia: Ostreidae), Ostrea oleomargaritaJournal of Zoological Systematics and Evolutionary Research. 7058975. DOI: 10.1155/2022/7058975
Daniele Salvi, Manal Al-Kandari, P. Graham Oliver, Emanuele Berrilli,, and Matteo Garzia. 2023. Corrigendum: Salvi D, Al-Kandari M, Oliver PG, Berrilli E, Garzia M. 2022. Cryptic marine diversity in the northern Arabian Gulf: an integrative approach uncovers a new species of oyster (Bivalvia: Ostreidae), Ostrea oleomargaritaJournal of Zoological Systematics and Evolutionary Research. 7058975. DOI: 10.1155/2022/7058975. ZooKeys. 1143: 89-92.  DOI:  10.3897/zookeys.1143.100087