Molecular phylogenetics of Caribbean Micrathena (Araneae : Araneidae) suggests multiple colonisation events and single island endemism

Abstract

The terrestrial biota of the Caribbean islands includes many lineages, some whose presence on the islands dates back some 35–40 million years ago, when land bridges are thought to have linked islands to continents, and others that have colonised more recently via dispersal. The New World spiny orb-weavers (Micrathena Sundevall, 1833) are a diverse group of mostly Neotropical spiders. Eight species have been described on the Greater Antilles islands: three widespread and five single island endemics. Here, using three molecular markers (16S rRNA, ITS-2 and COI) we provide a preliminary phylogenetic test of the taxonomy and biogeography of Caribbean Micrathena through the first molecular phylogeny of the genus. Our analyses support monophyly of the genus, but not that of Caribbean Micrathena with at least 3–4 colonisations from South America. We sampled six of the eight nominal Caribbean species (M. banksi, M. cubana, M. similis, M. forcipata, M. horrida, M. militaris), but demark eight divergent genetic lineages that all are single island endemics, and morphologically distinct. Thus a revision of the taxonomy of Caribbean Micrathena is needed. Our results function foremost to guide more thorough taxon sampling of Micrathena that enable more rigorous assessments of its diversity and biogeography in the Caribbean.

Phylogeography of a good Caribbean disperser: Argiope argentata (Araneae, Araneidae) and a new ‘cryptic’ species from Cuba

“…The intermediate dispersal model (Agnarsson et al 2014; Agnarsson and Kuntner 2012; Claramunt et al 2012; Diamond et al 1976) predicts that species richness across archipelagos peaks in intermediate dispersers but is comparatively low in excellent dispersers where oceanic barriers are less effective. Our findings are consistent with this model – Argiope spiders are effective dispersers and unlike most arachnid lineages studied in the Caribbean where single island endemism is prominent (Cosgrove et al 2016; Crews and Gillespie 2010; Dziki et al 2015; Esposito et al 2015; McHugh et al 2014) Argiope have undergone little diversification in the Caribbean. A similar pattern was found, for example, in some Selonops lineages in the Caribbean (Crews et al 2010) and in the nephilids of the western Indian Ocean islands.…”

“…Nevertheless, specimens from Cuba were deeply divergent from the remaining areas in all analyses, which we take as evidence for discovery of a cryptic species here described as Argiope butchko sp. n. ‘Hidden’ taxonomic diversity in the Caribbean is being revealed in multiple lineages by the CarBio project (Cosgrove et al 2016; Dziki et al 2015; Esposito et al 2015; McHugh et al 2014) and future work aims to test taxonomic hypotheses in other ‘widespread’ arachnid species that range from excellent to relatively poor dispersers and thus test the intermediate dispersal model at various taxonomic levels.…”

“…To amplify COI we used the primers LCO 1490 and HCO 2198 (Folmer et al 1994). PCR conditions and sequencing protocols were described previously (Bloom et al 2014; McHugh et al 2014). Sequences were submitted to GenBank (see Suppl.…”

“…Single-island endemism is common in successfully colonizing lineages (Arnedo and Gillespie 2006; Arnedo et al 2007; Gillespie 2005; Gillespie et al 2008; Zhang and Maddison 2012), a pattern consistent across taxa, islands and archipelagos including the Caribbean (Alayon 2006; Cosgrove et al 2016; Crews and Gillespie 2010; Dziki et al 2015; Esposito et al 2015; McHugh et al 2014; Zhang and Maddison 2012). This pattern is also found in many other invertebrates, and in vertebrates and plants (Ricklefs and Birmingham 2008).…”

From Gondwana to GAARlandia: Evolutionary history and biogeography of ogre‐faced spiders (Deinopis)

“…Most biogeographic research in the Caribbean has focused primarily on vertebrates (Dávalos, ; Glor, Losos, & Larson, ; Hedges et al., ; Hrbek, Seckinger, & Meyer, ; Murphy & Collier, ; Říčan et al., ; Sato et al., ) and plants (Salzman & Judd, ; Santiago‐Valentin & Olmstead, ; Skean, ; Zona, ). There have been a few recent studies on invertebrates (Hall, Robbins, & Harvey, ; Matos‐Maraví et al., ; Morrone, ; Sourakov & Zakharov, ) including spiders (Crews & Gillespie, ; Dziki, Binford, Coddington, & Agnarsson, ; McHugh et al., ) and other arachnids (Cosgrove, Agnarsson, Harvey, & Binford, ; Esposito et al., ). These studies have found mixed support for vicariance (Chakrabarty, ; Dziki et al., ; Matos‐Maraví et al., ; Říčan et al., ) and dispersal (Crews & Gillespie, ; Glor et al., ; McHugh et al., ; Sato et al., ) depending on the biology and characteristics of each lineage.…”