Phylogeny and Evolutionary Radiation in Seasonal Rachovine Killifishes: Biogeographical and Taxonomical Implications
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64 (2): 177 – 192 © Senckenberg Gesellschaft für Naturforschung, 2014. 25.7.2014 Phylogeny and evolutionary radiation in seasonal rachovine killifishes: biogeographical and taxonomical implications Wilson J. E. M. Costa Laboratory of Systematics and Evolution of Teleost Fishes, Institute of Biology, Federal University of Rio de Janeiro, Caixa Postal 68049, CEP 21944-970, Rio de Janeiro, Brasil; wcosta(at)acd.ufrj.br Accepted 26.v.2014. Published online at www.senckenberg.de/vertebrate-zoology on 15.vii.2014. Abstract A phylogenetic analysis combining available mitochondrial DNA sequences (total of 3,339 bp) and 161 morphological characters for 22 species of rachovine genera (Aphyolebias, Austrofundulus, Gnatholebias, Llanolebias, Micromoema, Moema, Neofundulus, Pterolebias, Rachovia, Renova, Terranatos, and Trigonectes), and 16 outgroups, supports monophyly of the group containing genera endemic to the Orinoco river basin and adjacent coastal drainages. Results of the present analysis are compared to previous studies. The tree topology indicates that the genera Moema and Rachovia as presently delimited are paraphyletic; consequently, Aphyolebias and Austrofundulus are respectively placed in the synonymy of Moema and Rachovia. This study also indicates that rachovines were in the past geographically restricted to the Amazonas-Paraguay area where diversification in niche exploitation was constrained by competition with sympatric mem- bers of older seasonal fish lineages. Rachovines later reached the Orinoco basin and adjacent coastal drainages by dispersal through the Paleo-Amazonas river basin, when major evolutionary radiation taken place. Key words Amazon Forest, Amazonas river, Orinoco river, Phylogeny, Biogeography. Introduction Independent molecular phylogenies (HRBEK & LARSON, nomenclatural priority over other suprageneric names in- 1999; MURPHY et al., 1999) using mitochondrial DNA volving the group. (mt-DNA) sequences have corroborated a group of sea- The Rachovini, as herein delimited, was not recog- sonal killifishes, endemic to central and northern parts of nised in former phylogenetic analyses, which used only South America, including the present genera Aphyolebias a few informative morphological characters for species COSTA, 1998, Austrofundulus MYERS, 1932, Gnatholebias of this group (PARENTI, 1981; COSTA, 1990b, 1998). All COSTA, 1998, Llanolebias HRBEK & TAPHORN, 2008, Mi species of this group are seasonal fishes, uniquely found cro moema COSTA, 1998, Moema COSTA, 1989, Neo fun in temporary pools formed during the rainy seasons, a dulus MYERS, 1924, Pterolebias GARMAN, 1895, Ra cho unique life style occurring both in American and African via MYERS, 1927, Renova THOMERSON & TAPHORN, 1995, aplocheiloid killifishes (e.g., PARENTI, 1981; COSTA, Terranatos TAPHORN & THOMERSON, 1978, and Tri go 1998). As already noted by COSTA (1998), some mor- nectes MYERS, 1925. This group is herein referred as phological features have independently arisen in differ- tribe Rachovini, a name erected in COSTA (1990a) having ent seasonal fish lineages, generating some ambiguity in ISSN 1864-5755 177 W.J.E.M. Costa: Phylogeny and evolutionary radiation in seasonal rachovine killifishes phylogenetic analyses. Consequently, some rachovines 1991), and Rivulus cylindraceus POEY, 1860. A com- were formerly considered to be more closely related to plete list of material examined appears in COSTA (2012). members of other seasonal fish lineages than to most ra- Fragments of the following mt-DNA genes were ana- chovines, but subsequent morphological phylogenies di- lysed: cytochrome b (cytb), cytochrome oxidase I (cox1), rected to part of rachovines (COSTA, 2005) or to another 12S ribosomal RNA (12S) and 16S ribosomal RNA (16s) rivulid clade (COSTA, 2011a) have reported characters po- first analysed by MURPHY et al. (1999), and, transfer tentially diagnostic for the tribe. On the other hand, mo- RNAs for valine, glutamine, methionine, tryptophan, lecular phylogenetic studies have indicated conflicting alanine, asparagines, cysteine, and tyrosine, and NADH relationships among rachovine genera (HRBEK & LARSON, dehydrogenase subunit II (ND2), first analysed byH RBEK 1999; MURPHY et al., 1999). These studies used slightly & LARSON (1999); protocols for extraction, amplifica- different set of terminal taxa and distinct gene samples tion and sequencing, tests for differential saturation, and of the mitochondrial genome. As a result of incongru- GenBank accession numbers are available in HRBEK & ent phylogenies, relationships among some rachovine LARSON (1999) and MURPHY et al. (1999). Sequences genera are still poorly understood. The primary objective were aligned using Clustal-W (CHENNA et al., 2003) and of the present study is to concatenate mt-DNA available subsequently optimized manually; regions of sequences in those studies in a single analysis, combining them to showing high degree of ambiguity for alignment, mak- morphological taxa in order of to search the best phy- ing homology of sites questionable, were deleted from logenetic tree using a total evidence approach, which is the final aligned sequence, which had a total of 3,339 the basis for a discussion on evolutionary radiation and bp. Morphological characters were obtained from recent biogeography of rachovines. phylogenetic studies involving rachovines (COSTA, 1998, 2005, 2011a), besides new characters derived from the comparative analysis of brain morphology and osteologi- cal and myological structures. Morphological characters with a derived character state occurring in a single ter- Material and methods minal taxon were excluded. The analysis includes a total of 161 characters, listed in Appendix 1, where charac- ter statements are formatted following SERENO (2007); complete descriptions of morphological traits will ap- Terminal taxa were species with mt-DNA sequences avail- pear elsewhere (COSTA, in prep.) Osteological prepara- able in GenBank, including 22 rachovine in-group taxa, tions (c&s) were made according to TAYLOR & VAN DYKE Aphyolebias peruensis (MYERS, 1954), Austrofundulus (1985). Terminology for osteological structures followed guajira HRBEK, TAPHORN & THOMERSON, 2005, Austro COSTA (2006); for frontal squamation, HOEDEMAN (1958); fundulus limnaeus SCHULTZ, 1949, Austrofundulus tran for cephalic neuromast series, COSTA (2001); for brain silis MYERS, 1932, Gnatholebias hoignei (THOMERSON, morphology, EASTMAN & LANOO (2003); and for striated 1974), Gnatholebias zonatus (MYERS, 1935), Llanolebias muscles, WINTERBOTTOM (1974). Distribution of character stellifer (THOMERSON & TURNER, 1973), Micromoema xi states of morphological characters among terminal taxa pho phora (THOMERSON & TAPHORN, 1992), Moema pi appears in Appendix 2. The phylogenetic analysis was riana COSTA, 1989, Moema staecki (SEEGERS, 1987), carried out with maximum parsimony (MP), performed Neo fundulus ornatipinnis MYERS, 1935, Neofundulus with TNT 1.1 (GOLOBOFF et al., 2008), using the ‘tradi- pa raguayesis (EIGENMANN & KENNEDY, 1903), Rachovia tional’ search and setting random taxon-addition rep- brevis (REGAN, 1912), Pterolebias longipinnis GARMAN, licates to 10, tree bisection-reconnection branch swap- 1895, Pterolebias phasianus COSTA, 1988, Rachovia ping, multitrees in effect, collapsing branches of zero- ma culipinnis (RADDA, 1964), Rachovia pyropunctata length, characters equally weighted, and a maximum of TAPHORN & THOMERSON, 1978, Renova oscari THOMERSON 1,000 trees saved in each replicate; branch support was & TAPHORN, 1995, Terranatos dolichopterus (WEITZMAN assessed by bootstrap analysis, using a heuristic search & WOURMS, 1967), Trigonectes aplocheiloides HUBER, with 1,000 replicates. Character states of all morphologi- 1995, Trigonectes balzanii (PERUGIA, 1891), and Tri go cal characters were treated as unordered and genes were nectes rubromarginatus COSTA, 1990, and 16 out-group analysed giving equal weight to all sites. Molecular and taxa, Anablepsoides stagnatus (EIGENMANN, 1909), At morphological data were analysed together and separate- lan tirivulus luelingi (SEEGERS, 1984), Atlantirivulus san ly using MP; molecular data alone were also analysed ten sis (KÖHLER, 1906), Cynodonichthys tenuis (MEEK, with Maximum Likelihood (ML) methods using MEGA 1904), Cynodonichthys weberi (HUBER, 1992), Fun du lo 5 (TAMURA et al., 2011). Independent analyses compris- panchax gardneri (BOULENGER, 1911), Krypto lebias mar ing gene partitions, each encompassing individual genes moratus (POEY, 1880), Laimosemion strigatus (REGAN, or group of contiguous gene sequences were performed 1912), Maratecoara formosa COSTA & BRASIL, 1995, to assess the phylogenetic content of each genetic mark- Maratecoara lacortei (LAZARA, 1991), Melanorivulus er. Habitat preferences were inferred from field observa- punc tatus (BOULENGER, 1895), Nematolebias whitei (MY tion made during 16 collecting trips between 1986 and ERS, 1942), Pituna poranga COSTA, 1989, Pa pi lio lebias 2013 in all the main areas within the geographical range bitteri (COSTA, 1989), Plesiolebias aruana (LAZARA, of rachovines. 178 VERTEBRATE ZOOLOGY — 64 (2) 2014 Fig. 1. Maximum Parsimony (MP) tree of relationships among 22 species of rachovine killifi shes (outgroups not depicted) combining mitochondrial DNA (mt-DNA) sequences (3,339 bp) and 161 morphological characters (tree length 12,728). Numbers near branch are bootstrap values above 50 %; above values for the combined analysis, below values for the Maximum Likelihood analysis of mt-DNA