Cosmopolitan abyssal lineages? A systematic study of East Pacific deep-sea squat lobsters (Decapoda: Galatheoidea: Munidopsidae)

Abstract

Munidopsid squat lobsters are among the most abundant decapods at abyssal depths and the most diverse squat lobster group in the East Pacific region. During recent cruises along the East Pacific, many deep-sea squat lobsters were collected. Among these, we described five new munidopsid species supported both by morphological characters and molecular phylogenetics: Munidopsis girguisi sp. nov., M. nautilus sp. nov., M. testuda sp. nov., M. cortesi sp. nov. and M. hendrickxi sp. nov. We also report new records of several Munidopsis species across the East Pacific that increase the species distribution ranges. Here, we reconstructed the phylogenetic relationships of the East Pacific species in relation to other Galatheoidea using one nuclear and two mitochondrial gene fragment(s); we also performed single locus species delimitation analyses to explore the species status of various East Pacific munidopsid taxa. The new taxa were photographed, illustrated and imaged with micro-computed tomography. The phylogenetic results show that: (1) Janetogalathea californiensis, previously included in the family Galatheidae, nests within Munidopsidae; (2) the phylogenetic position of Phylladiorhynchus and Coralliogalathea as belonging in Galatheidae is not supported; and (3) Munidopsis is paraphyletic, agreeing with recent systematic hypotheses. Short genetic distances and species delimitation analyses suggested that a clade mostly constituted by abyssal species might include fewer species than currently considered, as species show a wider geographic range than previously considered, conforming with traditional hypotheses of cosmopolitanisms in abyssal species.ZooBank: urn:lsid:zoobank.org:pub:CED9EB18-7061-47A7-B2FF-7F1DAFCC7B12.

New records of the squat lobster genus Munidopsis Whiteaves, 1874 (Crustacea, Decapoda, Munidopsidae) from the deep sea off Taiwan

“…The mitochondrial COI gene is considered as rather conservative in the genus Munidopsis between populations and among sibling species (cf. Jones and Macpherson 2007 ; Thaler et al 2014 ; Coykendall et al 2017 ; Dong et al 2019 ; Rodríguez-Flores et al 2023 ). Thus, the phylogenetic hypothesis based on COI data by Rodríguez-Flores et al (2023) concluded that M. albatrossae and M. aries , as well as many other abyssal species of this genus, are not distinguished as different species.…”

“… Jones and Macpherson 2007 ; Thaler et al 2014 ; Coykendall et al 2017 ; Dong et al 2019 ; Rodríguez-Flores et al 2023 ). Thus, the phylogenetic hypothesis based on COI data by Rodríguez-Flores et al (2023) concluded that M. albatrossae and M. aries , as well as many other abyssal species of this genus, are not distinguished as different species. Nevertheless, such low genetic divergences may be more apparent than real because increasing depth could reduce the rate of substitution ( Rodríguez-Flores et al 2022b ).…”

“…The galatheoid family Munidopsidae is recognized to include five extant genera ( Ahyong et al 2010 , 2011 ; Rodríguez-Flores et al 2023 ): Galacantha A. Milne-Edwards, 1880; Janetgalathea Baba & Wicksten, 1997; Leiogalathea Baba, 1969; Munidopsis Whiteaves, 1874; and Shinkaia Baba & Williams, 1998. Among these genera, Munidopsis is the most speciose and represented by about 300 species worldwide, although abyssal species might include fewer species than currently considered (cf.…”

“…Among these genera, Munidopsis is the most speciose and represented by about 300 species worldwide, although abyssal species might include fewer species than currently considered (cf. Rodríguez-Flores et al 2022a , 2023 ). From Taiwanese waters, 37 species of the genus have been recorded ( Baba et al 2009 ; Lin and Chan 2011 ; Lin et al 2013 ; Osawa et al 2013 ), but recent deep-sea cruises have still discovered more species, including a giant Munidopsis specimen (carapace length including rostrum, 100.0 mm) never collected before.…”

Multi-ocean distribution of a brooding predator in the abyssal benthos

“…Numerous later studies have shown that the abyssal fauna has a rich species diversity and the cosmopolitan distribution of many species is contentious (e.g. 12 – 17 ). The extent of geographic range may influence species ability to recover after disturbance but at the same time wrong estimation of such range may lead to overestimation of the resilience potential of certain taxon.…”