Phylogenetics links monster larva to deep‐sea shrimp

Abstract

Mid-water plankton collections commonly include bizarre and mysterious developmental stages that differ conspicuously from their adult counterparts in morphology and habitat. Unaware of the existence of planktonic larval stages, early zoologists often misidentified these unique morphologies as independent adult lineages. Many such mistakes have since been corrected by collecting larvae, raising them in the lab, and identifying the adult forms. However, challenges arise when the larva is remarkably rare in nature and relatively inaccessible due to its changing habitats over the course of ontogeny. The mid-water marine species Cerataspis monstrosa (Gray 1828) is an armored crustacean larva whose adult identity has remained a mystery for over 180 years. Our phylogenetic analyses, based in part on recent collections from the Gulf of Mexico, provide definitive evidence that the rare, yet broadly distributed larva, C. monstrosa, is an early developmental stage of the globally distributed deepwater aristeid shrimp, Plesiopenaeus armatus. Divergence estimates and phylogenetic relationships across five genes confirm the larva and adult are the same species. Our work demonstrates the diagnostic power of molecular systematics in instances where larval rearing seldom succeeds and morphology and habitat are not indicative of identity. Larval–adult linkages not only aid in our understanding of biodiversity, they provide insights into the life history, distribution, and ecology of an organism.

Extreme morphologies of mantis shrimp larvae

“…Lewis, 1951;Johnson, 1971;Palero et al, 2014) or polychelid decapods (Williamson and Rice, 1996;Martin, 2014;Torres et al, 2014;Eiler et al, 2016) or also the slightly smaller larva formerly known as "Cerataspis monstrosa" (aristeid shrimp; Bracken-Grissom et al, 2012). Four types of mantis shrimp larvae have generally been distinguished, two early larval types and two later larval types ( Fig.…”

The identity of juvenile Polynoidae (Annelida) in the Southern Ocean revealed by DNA taxonomy, with notes on the status of Herdmanella gracilis Ehlers sensu Augener

“…Monaghan et al, 2006;Vogler and Monaghan, 2007;Hamilton et al 2011). Additionally, DNA barcoding has proved successful in linking different developmental stages of the same species in a wide range of animal taxa, such as shrimps (Shank et al, 1998), beetles (Ahrens et al, 2007), marine invertebrates (Webb et al, 2006;Heimeier et al, 2010;Bracken-Grissom et al, 2012) and fish (Pegg et al, 2006;Valdez-Moreno et al, 2010).…”

“…In the marine environment, plankton and nekton collections commonly include larval and juvenile developmental stages that differ from their adult counterparts in their morphology. Early taxonomists, often unaware of the existence of the larval stages, sometimes misidentified these morphologies as independent adult lineages (Bracken-Grissom et al, 2012). Past approaches to these problems included rearing experiments in aquaria (Richards and Saksena, 1980;Haynes, 1982) or in situ (Haynes, 1979).…”

Molecular phylogeny of the deep‐sea penaeid shrimp genus Parapenaeus (Crustacea: Decapoda: Dendrobranchiata)

“…DNA barcoding has been particularly useful in identifying the different stages or morphotypes of the same species in crustaceans (e.g. Tang et al 2010;Bracken-Grissom et al 2012;Chang et al 2014;Palero et al 2014). More genetic data and sampling from P. ruberoculatus males as well as the different forms in P. australiensis will confirm whether the present interpretation is accurate.…”