A Mysterious World Revealed: Larval-Adult Matching of Deep-Sea Shrimps from the Gulf of Mexico
Mary Wicksten
Round 1
Reviewer 1 Report
Review for the paper "A bizarre and mysterious world revealed: Larval-adult matching of deep-sea decapods from the Gulf of Mexico and adjacent waters" by Carlos Varela and Heather Bracken-Grissom submitted to "Diversity".
General comment.
Overall, there is an increasing interest to measure marine biodiversity and revealing the rate at which it is changing. Zooplankton communities are a critical link between primary producers and the higher trophic levels. To monitor their responses to environmental change a list of taxa consisting of a zooplankton assemblage is required. Understanding zooplankton biodiversity is hindered by a crucial problem to detect correctly the species present. The taxonomy and identification of marine zooplankton have traditionally been based on morphometry and descriptive characteristics assessed with a light microscope. However, due to the similar morphology and restricted diagnosis of many zooplankton taxa, positive identification is frequently complicated, challenging and time consuming. A lot of juvenile instars and larvae can be morphologically identified with ease to only Phylum or Class, and rarely to Order or Family. Molecular techniques based on DNA sequencing may be a useful tool in such cases. One of the less studied zooplankton group is larval Decapoda inhabiting deepwater regions of the Gulf of Mexico. The authors have undertaken the case study to reveal the diversity pattern of planktonic stages of decapod crustaceans using DNA barcoding. To distinguish the taxa they used the mitochondrial ribosomal large subunit 16S (16S) and the protein coding cytochrome oxidase subunit 1 (COI). Previous sequences and original data were used to generate phylogenetic trees of 16 developmental stages from the infraorder Caridea and the suborder Dendrobranchiata. Data were collected during 8 cruises. The authors used standard sampling devices (a Multiple Opening/Closing Net, Environmental Sensing System (MOC-10), a 9m2 Tucker trawl with a cod-end) and standard processing procedures. The authors provided a list of illustrations and a taxonomical guide for many larval groups of Decapoda from the Gulf of Mexico. Novel data based on DNA barcoding expand our knowledge about the diversity of larval Decapoda in the Gulf of Mexico. I can recommend this paper for publication in Diversity after minor revisions.
Specific remarks.
L120. Please, provide a map of the study area with sampling stations.
L130. Please, note that MOCNESS plankton net was used to collect large zooplankton.
L137. Please, provide the total number of samples collected.
L196. Please, provide the total number of individuals analyzed in the study.
Fig. 3. Please, increase the resolution of the Figure for better presentation of the phylogeny.
Author Response
All the response alre in the file attached.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
After a quick reading of the manuscript, I compared the illustrations with a sampling of the many midwater decapod larvae taken in midwater trawls by the ship "Alaminos" in the northern and western Gulf of Mexico in 1964-69. These old larval specimens are not suitable for genetic analysis but match some previous descriptions at least to genus. I was puzzled that there were no matches among the described larvae to Acanthephyra purpurea or Systellaspis debilis, of which our university has hundreds of specimens; nor to Stylopandalus richardi or Plesionika martia, both common midwater carideans. But there are matches to Alvinocaris and Eugonatonotus, both benthic species. As best as I can tell, the genetic matches are good but I would like further speculation about why the latter two species showed up in the collections while far more common species did not.
The Introduction could stand some shortening. The text of the paper concerns shrimp-like decapods: Pleocyemata and Dendrobranchiata, not any crabs or lobsters. While there is a great deal of information on life histories of crabs and lobsters, there also is a good amount of information on commercial shrimps (Penaeidae, Pandalidae). Information on the larval stages in the Gulf of Mexico in general is scanty. The attractive opening figures (1 and 2) are pretty but do not pertain to the work, especially figure 2. Do the authors have some sharp photographs of the larval stages in life, or perhaps a comparative figure showing the larva and the adult?
Author Response
All the responses are in the file attached.
Author Response File: Author Response.pdf
Reviewer 3 Report
See attached file.
Comments for author File: Comments.pdf
Author Response
All the responses are in the attached file.
Author Response File: Author Response.pdf
