Congruent Molecular and Morphological Diversity of Macaronesian Limpets: Insights into eco-evolutionary Forces and Tools for Conservation

Abstract

Combined analysis of genetic and morphological variation can provide synergistic insights into eco-evolutionary forces shaping biodiversity, as well as tools for conservation and management. Macaronesian limpets are undergoing severe declines due to overexploitation which calls for an evaluation of the evolutionary significance and taxonomic status of populations. This study details the analysis of genetic (mtDNA sequencing) and morphological (geometric analysis of shell shape) variation among Macaronesian populations of Patella aspera, P. rustica, and P. candei. In the case of P. aspera and P. rustica, this also included analysis of mainland conspecifics. mtDNA revealed distinct phylogeographic patterns for the three species. For both P. aspera and P. rustica Macaronesian and continental samples were reciprocally monophyletic, with shallower, and distinct, phylogeographic structure within both clades. For P. candei, the Macaronesian endemic, three reciprocally monophyletic groups corresponding to (i) the Azores, (ii) Madeira and (iii) Selvagens and Canary Islands were resolved. The different patterns for each species are compatible with independent processes of colonization and demographic processes. Morphological differentiation matched the major phylogeographic groupings (i.e., Macaronesian v Continent for P. aspera and P. rustica; Azores/Madeira/Selvagens and Canary Islands for P. candei) compatible with such variation being shaped by genetic drift associated with distinct demographic histories of lineages as well as historical/recurrent selection pressures. The genetic/morphological congruence supports the formal recognition of at least three described P. candei subspecies. Moreover, the data prompt recommendation of the separate management of limpets from each archipelago. At present management efforts are hampered by illegal harvesting of limpets. From an applied viewpoint, this study confirms that morphology retains useful information on genetic status and thus represents a potentially cheap method applicable to limpet conservation.

Wing Geometric Morphometrics of Workers and Drones and Single Nucleotide Polymorphisms Provide Similar Genetic Structure in the Iberian Honey Bee (Apis mellifera iberiensis)

“…The ability of wing traits to capture a genetic pattern so strikingly similar to that inferred from hundreds of molecular loci spread across the 16 honey bee chromosomes [35,52] could be explained by a high heritability and a polygenic nature of wing shape. While the genetic basis of forewing venation is virtually unknown in most insects, including honey bees, it is likely that wing shape has a strong genetic control, as suggested by this and other studies which have also reported concordance between wing morphology and molecular markers, such as mtDNA and microsatellites [78][79][80][81][82][83].…”

Limpet larvae (Patella aspera Röding, 1798), obtained by gonad dissection and fecundation in vitro, settled and metamorphosed on crustose coralline algae

“…This timing is within the range of other limpet taxa, including species of the same genus with 4–15 days (Ribeiro, 2008; Guallart et al ., 2020; Ferranti et al ., 2021), as well as the genera Cellana with 4–6 days (Mau et al ., 2018) and Lottia with 6–12 days (Kay & Emlet, 2002; Nakano et al ., 2020). Although the timing for development in limpets is specific and temperature dependent (Ribeiro, 2008; Ferranti et al ., 2021), the short duration of the larval stages implies a limited dispersal phase, explaining the genetic and morphometric differences observed between the Macaronesian and continental populations (Côrte-Real et al ., 1996 a , 1996 b ; Weber & Hawkins, 2005; Carreira et al ., 2017).…”

Taxonomic re‐appraisal for toothfish (Dissostichus: Notothenioidea) across the Antarctic Polar Front using genomic and morphological studies

“…(2018). Congruent patterns of variation at genetic and ontogenetic markers have been shown to be highly informative with respect to stock structure analysis (Carreira et al ., 2017; Gwilliam et al ., 2018; McKeown et al ., 2015, 2017) and in this case suggest the existence of demographic stock structuring within both regions which should be recognised in spatial management strategies (Reiss et al ., 2009). Key to this will be elucidation of stock isolating mechanisms and the relative roles of physical vs .…”