Overlooked cryptic endemism in copepods: Systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida, Diaptomidae)

Abstract

a b s t r a c tOur comprehension of the phylogeny and diversity of most inland-water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the ''Cosmopolitanism Paradigm'' of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group.Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diaptomid subgenus Occidodiaptomus were investigated with the aim of comparing the patterns of morphological and molecular evolution in freshwater copepods. Three species currently lumped under the binomen Hemidiaptomus (Occidodiaptomus) ingens and two highly divergent clades within H. (O.) roubaui were distinguished, thus showing an apparent discordance between the molecular distances recorded and Occidodiaptomus morphological homogeneity, and highlighting a noteworthy decoupling between the morphological and molecular diversity in the subgenus.Current Occidodiaptomus diversity pattern is ascribed to a combined effect of ancient vicariance and recent dispersal events. It is stressed that the lack of sound calibration points for the molecular clock makes it difficult to soundly temporally frame the diversification events of interest in the taxon studied, and thus to asses the role of morphological bradytely and of accelerated molecular evolutionary rates in shaping the current diversity of the group.

Population genetic structure of Calanoides natalis (Copepoda, Calanoida) in the eastern Atlantic Ocean and Benguela upwelling system

“…They have been found in a wide range of crustacean taxa including calanoid copepods (Bucklin et al, 1999(Bucklin et al, , 2000Machida and Lin, 2017) and diaptomid calanoids (Thum and Harrison, 2009;Marrone et al, 2013). The aberrant sequences found in this study do not contain any stop codons or frame shifts, and therefore do not resemble classical nuclear mitochondrial pseudogenes (so called numts) that often contain InDels (Insertion/Deletions) and mutations at any codon position (Song et al, 2008;Buhay, 2009;Calvignac et al, 2011).…”

How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds

“…Afterwards, with the advent and spreading of molecular techniques, an ever increasing amount of evidences showed that as a rule, in clear antithesis with the ''Cosmopolitan paradigm'', inland water organisms belong to a high number of different species, and that these are characterized by a noteworthy degree of endemism (e.g. Korn et al, 2006;Belyaeva & Taylor, 2009;Bode et al, 2010;Komárek & Mareš, 2012;Krienitz & Bock, 2012;Marrone et al, 2013, and references therein). The taxa belonging to these species complex are sometimes hard or impossible to be told apart based on morphology (e.g.…”

“…At a within-species level, quite a low ongoing gene flow between conspecific populations is usually observed (Boileau et al, 1992), which contributes to the presence of marked phylogeographic structures in the vast majority of inland water taxa (e.g. Gómez et al, 2000;De Gelas & De Meester, 2005;Muñoz et al, 2008;Marrone et al, 2013). Actual genetic connectivity seems to be, as a rule, scarce to absent even among nearby conspecific populations (De Meester, 1996;Meglécz & Thiéry, 2005, Ketmaier et al, 2003, but see also Aguilar, 2011), or it is not possible to single out a coherent geographic pattern in the distribution of the genetic lineages (e.g.…”

“…Moreover, dispersal often occurs through multiple processes and vectors (Higgins et al, 2003). In this review, we will put a special focus on temporary water bodies, since these ecosystems represent biodiversity hotspots (Williams et al, 2001;Zacharias et al, 2007) and their functioning and conservation strictly depends on the dispersal and colonization abilities of their biota (Sahuquillo & Miracle, 2013;Marrone et al, 2013;Korn et al, 2013). Moreover, temporary ponds, alternating flooded and dry phases, add the duration of their ponding phase as a further temporal dimension to their ''insular features'' (Ebert & Balko, 1987;NaselliFlores & Barone, 2012).…”

First record of the North American cryptic invaderFerrissia fragilis(Tryon, 1863) (Mollusca: Gastropoda: Planorbidae) in the Middle East

“…Mega5 (Tamura, Peterson, Peterson, Stecher, Nei, & Kumar, 2011) was used to translate in amino acids the sequences of the proteincoding gene COI in order to check for the possible presence of frameshifts or premature stop codons, which would indicate the presence of sequencing errors or pseudogenes, which is a wellknown and wide-spread problem in invertebrates (e.g. Marrone, Lo Brutto, Hundsdoerfer, & Arculeo, 2013).…”