Phylogeny and evolution of shallow‐water squat lobsters (Decapoda, Galatheoidea) from the Indo‐Pacific

Abstract

Squat lobsters have a worldwide distribution and are highly visible crustaceans living in a broad range of habitats. In this study, partial sequences of two mitochondrial DNA genes (16S rRNA and COI) and a nuclear gene (H3) were obtained for all but one of the known species of the shallow-water genera Sadayoshia (Munididae) and Lauriea, Macrothea and Triodonthea (Galatheidae). Lauriea siagiani appeared to be phylogenetically closer to Triodonthea and Macrothea than to other Lauriea species, suggesting the need for taxonomic re-evaluation of these taxa. All species of Sadayoshia formed a monophyletic group that would have diverged during the Paleogene (around 50Mya). Our results support the hypothesis that the late Paleogene-Neogene transition was a period of rapid diversification for shallow-water species of both Galatheidae and Munididae in the Indo-Pacific region. This is probably related to high tectonic activity among the Eurasian, Philippine Sea, Indo-Australian and Pacific plates and corresponding changes in distribution of habitats and ocean currents during the late Paleogene. Finally, the tropical south-west Pacific province is identified as a major diversification centre for shallow-water squat lobsters, from where species dispersed to other Pacific and Indian Ocean regions

Deep‐sea squat lobster biogeography (Munidopsidae: Leiogalathea) unveils Tethyan vicariance and evolutionary patterns shared by shallow‐water relatives

“…Graph showing evolutionary speciation trends in squat lobsters of the superfamily Galatheoidea: number of reconstructed lineages, estimated in increments of 5 Ma, for Leiogalathea and other galatheoid squat lobsters from shallow‐waters ( Coralliogalathea , Lauriea , Sadayoshia ) and the deep sea ( Paramunida ) that overlap in their distribution (data for trend analysis compiled from this study and those of Rodríguez‐Flores, Macpherson, Buckley, et al, , after re‐treatment of the data from Cabezas et al, and Palero et al, ). Depth distribution for each squat lobster genus is indicated on the right of the graph…”

“…Vicariant sister species separated by thousands of kilometres have been also reported in Coralliogalathea ( C. humilis vs. C. minuta ) (Rodríguez‐Flores, Macpherson, Buckley, et al, ). As in related galatheid species, for instance Lauriea punctata, Sadayoshia edwarsii or Allogalathea babai (Baba et al, ; Palero et al, ), some Leiogalathea species exhibit a wide geographic distribution. Although not known for this genus, other related squat lobster species have free‐swimming planktonic larvae (Baba, Fujita, Wehrtmann, & Scholtz, ) that might occasionally drift with the ocean currents, making long‐distance dispersal events followed by establishment conceivable.…”

“…Our findings indicate that a major period of cladogenesis in Leiogalathea occurred 25–15 Ma (Late Oligocene to Early Miocene). Major diversification of coral reef fauna in the CIP is thought to have occurred approximately 25–20 Ma during the Paleogene–Neogene transition (Palero et al, ; Rodríguez‐Flores, Macpherson, Buckley, et al, ; Williams & Duda, ) when the most important Cenozoic plate boundaries were reorganized (Hall, ). Intense diversification was also occurring in deep‐sea taxa during this period (Cabezas et al, ; Eilertsen & Malaquias, ).…”

“…This system was previously used to reconstruct the biogeographic history of related shallow‐water squat lobsters (e.g. Palero et al, ; Schnabel et al, ). Our samples covered four realms: Tropical Atlantic, Western Indo‐Pacific, Central Indo‐Pacific and Eastern Indo‐Pacific.…”

“…Phylogenetic reconstructions in a temporal‐spatial framework of related shallow‐water ( Lauriea , Sadayoshia , and Coralliogalathea ) and deep‐sea ( Paramunida ) squat lobsters have been published in recent years (Cabezas et al, ; Palero, Robainas‐Barcia, Corbari, & Macpherson, ; Rodríguez‐Flores, Macpherson, Buckley, & Machordom, ). According to these studies, the Tropical Southwestern Pacific and the CT are the regions with highest species richness, and the Oligocene–Miocene transition was a period with extremely high cladogenetic rates.…”