Genetic and morphometric evidence for unresolved species boundaries in the coral genus Psammocora (Cnidaria; Scleractinia)

Abstract

A comparative morphological and molecular characterization of species boundaries between four species of the Scleractinian genus Psammocora, namely P. digitata, P. haimeana, P. profundacella and P. contigua was conducted. The definition of species boundaries in this genus has been the subject of few studies, in spite of the presence of ambiguous taxonomic distinction, and a revision of the genus has never been undertaken. The multivariate analyses of both descriptive and morphometric characters confirmed the distinction of P. digitata and P. contigua, conversely P. haimeana, P. profundacella and their intermediate morph differentiated on the basis of descriptive morphologic characters only. Morphometric characters alone allowed a less defined distinction between morphs, and morphological boundaries essentially intergraded in a gradient driven by enclosed corallite series characters.The phylogenetic analysis of a portion of the rDNA confirmed the morphological inferences, as P. digitata appears to be a distinct evolutionary lineage. Conversely, the other four morphs, P. contigua, P. haimeana, P. profundacella and their intermediate constitute a polytomic gene pool significantly distinct from P. digitata. Yet, P. contigua is significantly distinct from the other three morphs. Both morphological and molecular approaches suggested that P. haimeana, P. profundacella and their intermediate cannot be considered clearly distinct entities. Hybridization with other species of this genus not included in this study, or recent origin may have contributed to the polyphyly and lack of phylogenetic resolution of P. haimeana, P. profundacella and their intermediate morph. They appear to constitute a single gene pool showing morphological characters encompassing a gradient from the P. haimeana to the P. profundacella morphs. Such morphological variability possibly depends on environmental factors such as light conditions.

Species delimitation in the coral genus Goniopora (Scleractinia, Poritidae) from the Saudi Arabian Red Sea

“…Unfortunately, scleractinian morphology exhibits extensive phenotypic plasticity, high variability, and/or evolutionary convergence that often obscure natural patterns of evolution (e.g., Gittenberger and Hoeksema, 2006;Fukami et al, 2004;Todd, 2008;Flot et al, 2011;Budd et al, 2012). The integration of molecular tools with morphological analyses has proven to be powerful in clarifying misleading and complex phylogenies, with recent examples in the genera Pocillopora (Schmidt Roach et al, 2014), Psammocora (Stefani et al, 2008;Benzoni et al, 2010), and Desmophyllium (Addamo et al, 2016). In the present study, a multi-locus genetic approach provides the basis for a reevaluation of evolutionary-informative morphological features to assess species boundaries in Goniopora.…”

The New Systematics of Scleractinia: Integrating Molecular and Morphological Evidence

“…Colours differentiate adjacent families and are not unique for any taxa, except for genera assigned incertae sedis that are shown in black statistically using SeqPHASE (Flot 2010). Furthermore, direct sequencing of ITS has been carried out following PCR with primers demonstrating high fidelity for a single copy (Takabayashi et al 1998a(Takabayashi et al , b, 2003Lam and Morton 2003;Benzoni et al 2007Benzoni et al , 2010Benzoni et al , 2011Benzoni et al , 2012aBenzoni et al , b, 2014Mangubhai et al 2007;Stefani et al 2008b;Knittweis et al 2009;Huang et al 2011;Benzoni and Stefani 2012). Nevertheless, since the intra-individual variability of these nuclear markers is not fully understood (Chen et al 2004;Vollmer and Palumbi 2004), caution should be exercised even when using these primer sets.…”

Acanthophyllia deshayesiana (Michelin, 1850) Coral Species Is Not Synonym With Cynarina lacrymalis (Milne Edwards & Haime, 1848)

“…Coral specimens were bleached in sodium hyplocorite, rinsed with freshwater, and air-dried for morphological analysis. Morphological analysis were consist of morphometric and descriptive characters (Oppen et al, 2000;Wolstenholme et al, 2003;Stefani et al, 2008;Filatov et al, 2013;Kitano et al, 2014). Coral specimens were selected by the same size (the colony diameter range 4-8 cm).…”

“…High response of coral to environmental changes (Wolstenholme et al, 2003;Marti-Puig et al, 2014) have an impact on morphological pattern of the coral diversity, so it classified in a high plasticity organisms (Stefani et al, 2008;Huang et al, 2009;Schmidt-Roach et al, 2012). The diversity of coral morphology gives a trouble to identify live coral and classification system in the coral taxonomy.…”

“…However, the observation and measurement of coral using skeleton showed intra species variation and a high plasticity (Stefani et al, 2008). Therefore, there were many studies on the coral systematics by combining the morphological and molecular approach.…”