Deep Under the Sea: Unraveling the Evolutionary History of the Deep-Sea Squat Lobster Paramunida (Decapoda, Munididae)

Abstract

The diversification of Indo-Pacific marine fauna has long captivated the attention of evolutionary biologists. Previous studies have mainly focused on coral reef or shallow water-associated taxa. Here, we present the first attempt to reconstruct the evolutionary history-phylogeny, diversification, and biogeography-of a deep-water lineage. We sequenced the molecular markers 16S, COI, ND1, 18S, and 28S for nearly 80% of the nominal species of the squat lobster genus Paramunida. Analyses of the molecular phylogeny revealed an accelerated diversification in the late Oligocene-Miocene followed by a slowdown in the rate of lineage accumulation over time. A parametric biogeographical reconstruction showed the importance of the southwest Pacific area, specifically the island arc of Fiji, Tonga, Vanuatu, Wallis, and Futuna, for diversification of squat lobsters, probably associated with the global warming, high tectonic activity, and changes in oceanic currents that took place in this region during the OligoceneMiocene period. These results add strong evidence to the hypothesis that the Neogene was a period of major diversification for marine organisms in both shallow and deep waters.

A comprehensive and integrative reconstruction of evolutionary history for Anomura (Crustacea: Decapoda)

“…Recent studies based on the munidid squat-lobster genus Paramunida suggest that dramatic environmental change may provide great geological and habitat complexity, which in turn promotes isolation and rapid diversification [78]. The fact that both families, chirostylids and munidids, diverged during the Late Triassic (see Figure 4) and currently occupy deep-sea habitats suggests that similar geological and environmental changes may also have driven major diversification within the Munididae, which shifted habitats at some point because the Jurassic forms are nearly all coral-reef associated.…”

New sibling species and new occurrences of squat lobsters (Crustacea, Decapoda) from the western Indian Ocean

“…However, the evolutionary value of the different morphological characters must be determined in a wide study on the phylogeny of the family Munididae. This study (actually in progress) would solve the extreme morphological convergence and heterogeneity in the divergence values within genera and species Cabezas et al 2012).…”

A new species of Paramunida Baba, 1988 from the Central Pacific Ocean and a new genus to accommodate P. granulata (Henderson, 1885)

“…This close relationship has been confirmed by molecular evidence that have rendered this new genus as the sister group of Paramunida (Cabezas et al 2012, Cabezas and Chan 2014). Hendersonida gen. n. may be easily differentiated from Paramunida by having the dorsal surface of the carapace covered by granules and the distomesial spine of the antennal article 2 almost reaching the end of anterior prolongation of article 1.…”

“…Interestingly, the species Paramunida granulata (Henderson, 1885) is unique in having a granulated carapace and the distomesial spine of antennal article 2 very long, almost reaching the end of the anterior prolongation of article 1 (Baba 1988; Cabezas et al 2010). A previous phylogenetic study reported this species as the earliest offshoot within the genus in the early Oligocene (Cabezas et al 2012), which along with the above-mentioned marked morphological differences and a high genetic divergence indicate that this species followed an independent evolutionary trajectory (Cabezas et al 2010; Cabezas et al 2012; Machordom and Macpherson 2004). To reflect these findings, we herein propose a new genus, Hendersonida gen. n.…”

“…Although morphologically very similar to Paramunida , recent studies revealed that this species was phylogenetically and genetically very different from the other species of the genus (Cabezas et al 2010; Cabezas et al 2012; Cabezas and Chan 2014). This new lineage possesses two conspicuous diagnostic characteristics that make it easy to differentiate from species of Paramunida : (1) the armature of the dorsal surface of the carapace, and (2) the length of the distomesial spine of antennal article 2.…”