Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study Gérard Dubost To cite this version: Gérard Dubost. Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study. Comptes Rendus Biologies, Elsevier Masson, 2017, 10.1016/j.crvi.2017.02.001. hal-01485153 HAL Id: hal-01485153 https://hal.sorbonne-universite.fr/hal-01485153 Submitted on 8 Mar 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives| 4.0 International License G Model CRASS3-3495; No. of Pages 10 C. R. Biologies xxx (2017) xxx–xxx Contents lists available at ScienceDirect Comptes Rendus Biologies ww w.sciencedirect.com Ecology/E´ cologie Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study Caracte`res convergents entre un rongeur, le paca d’Ame´rique du Sud et un ruminant, le chevrotain aquatique d’Afrique : l’e´tude d’un cas exemplaire Ge´rard Dubost Muse´um national d’histoire naturelle, EGB–UMR 7204 MNHN–CNRS–UPMC, Me´nagerie du Jardin des plantes, 57, rue Cuvier, 75231 Paris cedex 05, France A R T I C L E I N F O A B S T R A C T Article history: The level of convergence between a rodent, the South American lowland paca Cuniculus Received 19 September 2016 paca, and a ruminant, the African water chevrotain Hyemoschus aquaticus, is analysed Accepted after revision 3 February 2017 using 231 characteristics belonging to different biological sectors. A convergence index is Available online xxx established based on the degree of rarity of each characteristic in each species compared to other members of its zoological group. Although the divergent characteristics are as Keywords: numerous as the convergent ones, the two species are globally similar. Convergent Lowland paca characteristics occur in all biological categories, but their rate varies a great deal among Water chevrotain them. From internal anatomy and osteology, through behaviour and ecology to the South America external appearance of the body, convergent characteristics are all the more frequent since Africa the biological category is directly implicated in the adaptation of animals to their external Convergence environment (lowland rainforest). However, only the individuals’ characteristics are Tropical rainforest concerned and not those of their population or social organisation. This could be due to differences between the communities of terrestrial mammals to which they belong. C 2017 Acade´mie des sciences. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/). R E´ S U M E´ Mots cle´s : Le niveau de convergence entre un rongeur, le paca Cuniculus paca d’Ame´rique du Sud, et Paca un ruminant, le chevrotain aquatique Hyemoschus aquaticus d’Afrique, a e´te´ analyse´ a` Chevrotain aquatique partir de 231 caracte`res relevant des diffe´rents secteurs de la biologie. Un indice de Ame´rique du Sud convergence a e´te´ e´tabli en fonction du degre´ de rarete´ de chaque caracte`re conside´re´ au Afrique sein du groupe zoologique auquel appartient chacune des espe`ces. Bien que les caracte`res Convergence divergents soient aussi nombreux que les convergents, les deux espe`ces sont dans Foreˆt tropicale humide l’ensemble convergentes. Les caracte`res convergents se rencontrent dans toutes les cate´gories biologiques, mais a` des degre´s tre`s divers. De l’anatomie interne et de Email address: [email protected]. http://dx.doi.org/10.1016/j.crvi.2017.02.001 C 1631-0691/ 2017 Acade´mie des sciences. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: G. Dubost, Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study, C. R. Biologies (2017), http:// dx.doi.org/10.1016/j.crvi.2017.02.001 G Model CRASS3-3495; No. of Pages 10 2 G. Dubost / C. R. Biologies xxx (2017) xxx–xxx l’oste´ologie jusqu’a` l’aspect externe du corps, en passant par le comportement et l’e´cologie, ils sont d’autant plus nombreux qu’ils sont directement implique´s dans l’adaptation des individus a` leur environnement exte´rieur (foreˆt tropicale). Cependant, les caracte´ristiques des individus sont les seules concerne´es, et non celles de leurs populations ou de leur organisation sociale. Cela pourrait eˆtre duˆ aux diffe´rences existant entre les communaute´s animales terrestres auxquelles appartiennent ces deux espe`ces. C 2017 Acade´mie des sciences. Publie´ par Elsevier Masson SAS. Cet article est publie´ en Open Access sous licence CC BY-NC-ND (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction This is due to the fact that changes are less obvious among the latter as a result of what are probably less restrictive Convergence between organisms is a widespread living conditions. phenomenon that has been known for a long time From the end of the Eocene to the Pliocene (from 34 to [1,2]. It concerns populations as well as species that 7 Myr ago), South America remained completely isolated belong to different classes and orders. Over the last from the rest of the world and evolved as an island. The 20 years, numerous debates have arisen about the validity nototrogomorph rodents present on this continent pro- of molecular data for proving a common origin of taxa and duced many cursorial species in the absence of other large for estimating the age at which they separated from one terrestrial mammals [14]. Even now, a number of South another [3]. However, a consensus exists concerning the American species are exceptional among rodents. A good fact that convergences are a priori the result of external example of this is the caviomorph lowland paca Cuniculus constraints. When species occur on different continents, it paca L., 1766 (Rodentia, Hystricomorpha), which inhabits must be supposed that the environmental conditions were the tropical forests of South America and appears to be comparable on these continents and have remained very similar to the African tragulid water chevrotain essentially unchanged until the present time. The conver- Hyemoschus aquaticus Ogilby, 1841 (Cetartiodactyla, gence is clear when two species have acquired the same Ruminantia) [15] (Fig. 1). Both species are medium-sized particularities that are infrequent or unique within their terrestrial species, typical of their tropical mammal respective group. Likewise, a species can show characte- communities. Because of their great similitude, it seems ristics that are infrequent or unique in its group but particularly interesting to see how the different biological common in that of another species. Despite the fact that characteristics of the paca are comparable to those of the convergences constitute an important question in biology water chevrotain, all the more so since the Rodentia are and evolution, few detailed studies have been undertaken thought to be separate from the Cetartiodactyla since the on this subject. For example, authors have made compa- Cretaceous, 66–78 Myr ago [16,17]. This should provide risons between populations or communities of mammals useful information about the extent and the limits of the based on apparent similarities in external features or diets convergence between two species. To my knowledge, a [4,5]. Other authors have analysed convergences between detailed study has never been undertaken on this point. clades or orders in morphology or metabolism, depending Over the last 40 years, several studies have focused on on the diet [6–9]. Fisher et al. [10] studied convergences in the diet, reproduction, ecology and behaviour of these two maternal care according to habitat characteristics. How- mammals. The goal of this work consists in comparing ever, these studies were conducted at a general level and their different characteristics and in analysing the often limited to a simple statement concerning a few biological sectors where convergences appeared. Given features. Overall, the most spectacular examples of the fact that these species live in a particular environment convergences among mammals are to be found among (lowland tropical rainforest), it might be expected that, aquatic, arboreal, gliding and subterranean species above all else, many physical characteristics would be [5,11–13] and, to a much lesser degree, terrestrial species. convergent. However, considering that the species must be Fig. 1. The hystricomorph rodent Cuniculus paca (a) and the ruminant artiodactyl Hyemoschus aquaticus (b). Please cite this article in press as: G. Dubost, Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study, C. R. Biologies (2017), http:// dx.doi.org/10.1016/j.crvi.2017.02.001 G Model CRASS3-3495; No. of Pages 10 G. Dubost / C. R. Biologies xxx (2017) xxx–xxx 3 adapted to their habitat, other categories of characteristics anatomy (31 characteristics), ecology (28 characteristics) should also be concerned, contrary to what could be and behaviour (59 characteristics). External appearance assumed (e.g., the ecology, as well as the behaviour, encompasses all of the external body features: shape, structure and organisation of the populations).