A Mysterious World Revealed: Larval-Adult Matching of Deep-Sea Shrimps from the Gulf of Mexico

Abstract

The identification of deep-sea (>200 m) pelagic larvae is extremely challenging due to the morphological diversity across ontogeny and duration of larval phases. Within Decapoda, developmental stages often differ conspicuously from their adult form, representing a bizarre and mysterious world still left to be discovered. The difficulties with sampling and rearing deep-sea larvae, combined with the lack of taxonomic expertise, argues for the use of molecular methods to aid in identification. Here, we use DNA barcoding combined with morphological methods, to match larval stages with their adult counterpart from the northern Gulf of Mexico and adjacent waters. For DNA barcoding, we targeted the mitochondrial ribosomal large subunit 16S (16S) and the protein coding cytochrome oxidase subunit 1 (COI). These data were combined with previous sequences to generate phylogenetic trees that were used to identify 12 unknown larval and two juvenile species from the infraorder Caridea and the suborder Dendrobranchiata. Once identified, we provide taxonomic descriptions and illustrations alongside the current state of knowledge for all families. For many groups, larval descriptions are missing or non-existent, so this study represents a first step of many to advance deep-sea larval diversity.

Rare yet everywhere: phylogenetic position of the enigmatic deep-sea shrimp Physetocaris microphthalma Chace, 1940 (Decapoda, Caridea)

“…The transportation could also occur during the larval phases (Shanks 2009). Little is known about deep-sea pelagic larvae, especially the total number of larval phases of a determined species and the morphological variations along the multiple stages (Varela and Bracken-Grissom 2021 b ). The only description of a gravid P. microphthalma female indicated three large eggs attached to the female’s pleopods (Foxton and Herring 1970).…”

DNA barcoding of crustacean larvae with two new records of Caridina gracilipes and Ptychognathus altimanus in the Western Region of Segara Anakan lagoon in Indonesia

“…Another constraint is the limited morphological characteristic of the crustacean larvae that can easily be used to diagnose the various crustacean species (Haug et al 2016). DNA barcoding has successfully solved these constraints using a short fragment of the cytochrome c oxidase 1 (COI) gene (Brando et al 2016;Rahman et al 2019;Palecanda et al 2020;Varela and Bracken-Grissom 2021). Several studies showed that the gene is a reliable barcode for crustacean barcoding (Raupah and Radulovici 2015;Matelatto et al 2016;Bhagawati et al 2020), including crustacean larvae (Palecanda et al 2020;Kusbiyanto et al 2020).…”