Deep-Sea Pycnogonids and Crustaceans of the Americas Michel E. Hendrickx Editor Deep-Sea Pycnogonids and Crustaceans of the Americas Editor Michel E. Hendrickx Inst Ciencias del Mar y Limnología National Autonomous University of Mexico Mazatlán, Mexico ISBN 978-3-030-58409-2 ISBN 978-3-030-58410-8 (eBook) https://doi.org/10.1007/978-3-030-58410-8 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifcally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microflms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. 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This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland This book is the result of a large effort by many American scientists and some of their overseas colleagues. Participation of academics from Latin America is particularly important as it throws new light on the deep-sea communities occurring off their countries’ coasts or, in some cases, in much larger areas within the geographic limits of the Americas. In this context, we wish to dedicate this book to two of our colleagues who actively participated in the early edition of this book but passed away while this process was taking place. Our Chilean colleague, Marco Antonio Retamal, was certainly a founding architect for the investigation in marine biology in Chile. Local expert in crustaceans, Marco Antonio was involved in a wide series of projects in his homeland, successfully forming and advising many students and young scientists during his career. Jorge López, from El Salvador, shared his interest between the fshery activities in Central America and a genuine, strong desire of studying the deep-water fauna in the region. An expert in fsheries and conservation issues, he often participated in regional meetings and local advisory panels. Marco Antonio and Jorge were not only distinguished academics with a profound interest in the biology and ecology of crustaceans and deep-water communities in Latin America, they were also dear friends to many of us. Their contribution to this book will remain forever a contribution to our knowledge of the deep-sea fauna of the Americas. Both true gentlemen, they will be remembered with respect, affection, and admiration. Preface Biogeography is a synthesis science integrating all the knowledge from geography, climatology, paleontology, zoology, and phylogenetic. The frst step to obtaining all this knowledge is a good sampling. Taxonomy is also essential to compare species between geographies. Nowadays, the knowledge acquired from diverse sources is collected in computer databases, and the largest ones in zoology and marine ecol- ogy are OBIS and WoRMS. However, before it can be integrated inside these data- bases, regional revisions are necessary to clarify the data. During the last decades, knowledge about the Arthropoda from the deep sea, especially Pycnogonida and Crustacea, increased considerably. The increase in marine deep-sea cruises with a mixture of boats, manned submersibles, or even ROVs brought several new species to light and more information about the way of life of these animals. Surprisingly, some areas on the planet remained very poorly known. It is the case for the coast of the Americas, more precisely South America, where a large gradient of latitudes offers a great diversity of ecosystems. The present volume is a very successful attempt to fll the gap in the knowledge on America’s crustacea. Crustaceans are present in all ecosystems and at any depths, from the pelagic to the benthic zones, and play a critical role in the food web. There are scavengers such as amphipods or isopods, plankton eaters like copepods, sus- pension feeders like cirripeds, and even carnivores such as lobsters or hermit crabs. At any given place in the oceans, these species they are essential to the functions of the ecosystems. The American continent, which extends from the Arctic to the Antarctic waters, separates the fauna between the Atlantic Ocean and the Pacifc Ocean. Very few benthic species, if any, can be found on both sides of the Americas. Furthermore, it is still unclear why the west American coast fauna is so different from the Indo-­ Pacifc one. The closing of the Isthmus of Panama, only 2.8 million years ago, explains partially this point as well as the long distances and strong currents separat- ing the East from the West Pacifc Ocean. Surprisingly, only 120 deep-sea species of decapods are known from the pacifc coast of the Americas considering that we fnd more than ten times this number in the Western Pacifc. Perhaps, the hypoxic conditions found along a large part of America’s coastlines, with the oxygen vii viii Preface ­minimum zone found within a large bathymetric range, could well be responsible for this poor fauna diversity. Besides the scientifc value, this kind of “regional” cataloguing of crustacea is important for the history of marine biology, drawing up a list of oceanographic ves- sels and expeditions undertaken along the American coasts. It is also an opportunity to acknowledge the dedicated work of community experts such as taxonomists or ecologists. Some articles are very original and precious considering that they describe very light and fragile animals diffcult to discover. They were collected in the deep sea, near the bottom or inside of the upper layer of the sediments, which required the use of sledge-dredges with micrometric meshes or box-corer. The catalogue of Pycnogonida from the Uruguayan continental slope has been enriched with several new deep-sea species. The groups of peracarid crustacea are insuffciently sampled anywhere in the world. It is well known that the harpacticoid copepods are very rich in species, present in all the benthic habitats and sometimes forming huge biomass. However, surprisingly, the review of the species from the Americas is only comprised of 22 families and 169 species. For the larger peraca- rids animals, the knowledge is a little bit better: 27 families and 118 species of amphipods for western Mexico only. The biology of the pelagic species living in the largest ecosystems of the world is still poorly known. Therefore, the observations about the reproduction and bathy- metric repartition of Nematocarcinu species in the Gulf of California are very use- ful. This group is present in all the oceans, characterized by their very long legs. For the frst time, the sex ratio has also been evaluated. A large sampling in the Gulf of Mexico by numerous oceanographic cruises brings good data on the 4 families and 14 species of Penaeoid shrimps. On the other side of South America, different cruises have collected 78 species of pelagic shrimps, Dendrobranchiata and Pleocyemata, between Peru and Tierra del Fuego. A large part of these is associated with the Nazca and Salas y Gomez Ridge sea- mounts. The lobsters are also included with the Nephropidae and Polychelidae of the Gulf of Mexico. The very large group of Galathoidea, one of the best-studied group of crustaceans in the world, has been studied on the Brazilian coast with the help of molecular tools. Fisheries in the deep sea are problematic. Generally, the growth rate of the tar- geted species is unknown as well as the generations turnover. In the case of crusta- cea, there is another diffculty: the halieutic models are validated for fsh, with linear growth, and not for crustacea with several moults. Studies on Lithodids from the Peruvian coast are bringing new useful data on species of Parolomis and Lithodes. In several places, the deep-sea populations of crustacea are already being overexploited. Other chapters bring interesting comments on decapod fsheries concerning 79 species in Uruguay and 181 species along the Brazilian coast, mainly on shrimps and geryonid crabs. For each species, an updated synonymy is given. The sampling of deep-sea crustacea along the Chilean coast is showing a change in the diversity between the warm waters in the north and sub-Antarctic waters south of Chiloé Preface ix Island brought by the Humbolt Current. The pacifc coast of Central America was also sampled from Guatemala to Panama. Conservation strategies are proposed to keep an equilibrium between healthy ecosystems and sustainable fsheries in the deep sea. In these environments, the biological conditions are different from the shallow-water fsheries, and the stocks are easily overexploited because the species have extreme longevity, slow growth rates, late maturity, and low fecundity. This volume highlights the ambitious exploration sampling programs in the deep sea to increase our knowledge of the fauna from North, Central, and South America. This knowledge could help to protect the deep-sea environment essential for the sustainability of our planet. MNHN-Nouméa Bertrand Richer de Forges Paris, France Prologue Although investigation in the Latin America part of the Americas’ deep waters has signifcantly increased in the last decades, there is still a profound gap between what we know about this environment in most of the northern hemisphere and in the southern hemisphere.