Foxed intra- and interspecific differentiation in <em>Leptogorgia</em> (Octocorallia: Gorgoniidae). A description of a new species based on multiple sources of evidence

Abstract

The challenges of delimiting and identifying marine invertebrate species impede estimations of true biodiversity. This is particularly true in the case of gorgonian diversity, in which only classical morphological characters (e.g. branching pattern, size and colouration of the colony and sclerites, etc.), which can be homoplastic and continuous, have been used. In this study, using an integrative taxonomic approach, we analysed two morphs initially considered as two eco-typical variants of Leptogorgia alba Duchassaing and Michelotti, 1864, living sympatrically in the littoral area of Ecuador. We explored the use of classical morphological and morphometric characters to delimit species in combination with the analyses of molecular markers (mtMutS, CoxII-Igr-CoxI, ITSs, and 28S rRNA) to infer phylogenetic relationships. Based on our results, two species should be considered, L. alba and a new species, L. manabiensis n. sp., which showed distinguishing morphological features that cannot be attributed to phenotypic plasticity. Both species also showed significant differences in morphometric, non-correlated characters in all size classes. The phylogenetic analyses showed a polyphyletic L. alba - L. manabiensis n. sp. species complex, and ancestral polymorphism and incomplete lineage sorting as possible evolutionary processes leading to this pattern. In conclusion, the combination of morphological and morphometric evidences provides the best support for the identification and delimitation of these challenging species. In addition, molecular analyses, mainly supported by nuclear markers, allow fundamental aspects of the evolutionary history of these organisms to be discerned.

Three new species of the sea fan genus Leptogorgia (Octocorallia, Gorgoniidae) from the Gulf of California, Mexico

“…Although sea fans are the most abundant benthic macroinvertebrates in the rocky reefs of the Gulf of California (Ulate et al 2016), their taxonomic identities and geographic delimitations in the Gulf of California have been historically poorly studied (Hernández 2014). Ten out the 30 nominal Leptogorgia species known for the Eastern Pacific have been described between 2000-2018 (Bayer 2000;Horvath 2011;Breedy et al 2012;Soler-Hurtado et al 2017b;Olvera et al 2018). Bayer (1981) estimated that about 50% of the sea fan species distributed in the Eastern Pacific were then unknown.…”

“…The long and acute spindles in L. enrici sp. nov., are only comparable in size to the spindles of Leptogorgia alba and Leptogorgia manabiensis Soler-Hurtado, Megina, Machordom & López-González, 2017(Soler-Hurtado et al 2017b. However, these long spindles are the dominant type in L. alba and L. manabiensis, they are broad with acute ends and crowded tubercles.…”

“…Species identification and morphological comparisons among Leptogorgia species were assessed following the standard techniques and nomenclature used by Verrill (1868), Breedy and Guzman (2007), Breedy et al (2009Breedy et al ( , 2012, and Horvath (2011) ( Table 1). We used standard taxonomic terminology and criteria to describe the three new species (Bayer et al Breedy and Guzman (2007), Horvath (2011), Breedy et al (2012), andSoler-Hurtado et al (2017b). All morphological measurements are given in mm.…”

Dead man’s fingers point towards new species: A taxonomic revision of Alcyonium aurantiacum with statistical discrimination methods and a survey of integrative taxonomy in Octocorallia

“…Currently, one of the main issues facing octocoral taxonomy is the uncertainty surrounding the extent and relevance of intraspecific morphological variation coupled with insufficient interspecific variation among many commonly used molecular markers (Pérez et al 2016), which makes it difficult to establish species limits (McFadden et al 2010). In octocorals, phenotypic plasticity is often examined with the aim of reviewing the taxonomic status of two or more morphotypes, which may then be split into several species (e.g., Soler-Hurtado et al 2017) or retained as one (e.g., Bilewitch et al 2010). Here, however, depth-related phenotypic plasticity was examined for K.…”

“…The appropriate splitting of species has specifically been linked to improved protection outcomes (Morrison et al 2009). Again, no panacea exists for this problem, but statistical analyses of morphometrics (as employed in Chapter 3) can provide additional, valuable information to aid species delimitation and reduce subjectivity (Gori et al 2012;Soler-Hurtado et al 2017; also see Mutanen and Pretorius 2007). Alternatively, the addition of morphological data directly into phylogenetic analyses may help, though this method is not often used in octocorals (Cairns and Wirshing 2018).…”