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Lobophorais a common tropical to temperate genus of brown algae found in a plethora of habitats including shallow and deep‐water coral reefs, rocky shores, mangroves, seagrass beds, and rhodoliths beds. Recent molecular studies have revealed thatLobophoraspecies diversity has been severely underestimated. Current estimates of the species numbers range from 100 to 140 species with a suggested center of diversity in the Central Indo‐Pacific. This study used three molecular markers (cox3,rbcL,psbA), different single‐marker species delimitation methods (GMYC,ABGD,PTP), and morphological evidence to evaluateLobophoraspecies diversity in the Western Atlantic and the Eastern Pacific oceans.Cox3 provided the greatest number of primary species hypotheses(PSH), followed byrbcL and thenpsbA.GMYCspecies delimitation analysis was the most conservative across all three markers, followed byPTP, and then ABGD. The most informative diagnostic morphological characters were thallus thickness and number of cell layers in both the medulla and the dorsal/ventral cortices. Following a consensus approach, 14 distinctLobophoraspecies were identified in the Western Atlantic and five in the Eastern Pacific. Eight new species from these two oceans were herein described:L. adpressasp. nov.,L. cocoensissp. nov.,L. colombianasp. nov.,L. crispatasp. nov.,L. delicatasp. nov.,L. dispersasp. nov.,L. panamensissp. nov., andL. tortugensissp. nov. This study showed that the best approach to confidently identifyLobophoraspecies is to analyzeDNAsequences (preferablycox3 andrbcL) followed by comparative morphological and geographical assessment.
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This content will become publicly available on March 1, 2026
Phylogeny of Arbacia Gray, 1835 (Echinoidea) Reveals Diversification Patterns in the Atlantic and Pacific Oceans
ABSTRACT AimThe aim of the current study is to conduct a comprehensive phylogenetic analysis of the genusArbaciato elucidate the evolution and phylogenetic relationships among all extant species and reevaluate the presence of geographic structure within species that have wide, fragmented distributions. LocationSpecimens ofArbaciawere collected from 34 localities spanning the Atlantic and Pacific Oceans, and the Mediterranean Sea. MethodsWe obtained sequences from three mitochondrial markers (COI, 16S and the control region and adjacent tRNAs) and two nuclear markers (28S and 18S; the latter ultimately excluded from the final analyses). Phylogenetic trees were constructed using maximum likelihood and Bayesian inference approaches. A time‐calibrated phylogenetic tree was inferred using a relaxed Bayesian molecular clock and three fossil calibration points. ResultsOur analysis supports the monophyly of the genusArbacia, including the speciesArbacia nigra(previously assigned to the monotypic genusTetrapygus). The new phylogenetic topology suggests an alternative biogeographic scenario of initial divergence between Atlantic and Pacific subclades occurring approximately 9 million years ago. The dispersal and subsequent diversification of the Pacific subclade to the southeast Pacific coincides with the onset of glacial and interglacial cycles in Patagonia. In the Atlantic subclade, the split betweenA. punctulataandA. lixulaoccurred 3.01–6.30 (median 3.74 million years ago), possibly associated with the strengthening of the Gulf Stream current connecting the western and eastern Atlantic. Our study also reveals significant genetic and phylogeographic structures within both Atlantic species, indicating ongoing differentiation processes between populations. Main ConclusionOur study provides valuable insights into the evolutionary history and biogeography of the genusArbaciaand highlights the complex interplay between historical climate changes and oceanic currents in shaping the distribution and diversification of echinoids in the Atlantic and Pacific Oceans.
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- PAR ID:
- 10580341
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Biogeography
- Volume:
- 52
- Issue:
- 3
- ISSN:
- 0305-0270
- Page Range / eLocation ID:
- 722 to 734
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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