New Genera and a New Species of Central American Salamanders, with a Review of the Tropical Genera (Amphibia, Caudata, Plethodontidae)
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NEW GENERA AND A NEW SPECIES OF CENTRAL AMERICAN SALAMANDERS, WITH A REVIEW OF THE TROPICAL GENERA (AMPHIBIA, CAUDATA, PLETHODONTIDAE) David B. and Paul Elias' ABSTRACT. A new genus and species of plethodontid bolitoglos- Chiropterotriton se seiiala como polifilttico y por lo tanto dos nuevos sin: salamander is described from material collected in northwestern generos se describen. Nototriton, nuevo gtnero, incluye el grupo Guatemala. Bradytriton silus new genus, new species, is unique in a picadoi de Chiropterotriton beta. Dendrotriton. nuevo gtnero, inclu- cornbination of structural characteristics that includes a laterally ye el grupo hromeliacia de Chiropterotriton beta. Las especies pre- cornpressed tail, stocky body with no clearly defined neck, and short, viamente incluidas en Chiropterotriton alfa permanecen como las slender limbs bearing syndactylous hands and feet. To diagnose the unicas representantes de este ghero. Ocho de 10s once generos neo- new genus, an analysis of the entire neotropical assemblage of pleth- tropicales se seiialan como monofiltticos. De 10s tres generos res- od(intid salamanders was undertaken. Approximately 138 species tantes, tanto Dendrotriton como Nototriton son monofiltticos en bel Jng to the supergenus Bolitoglossa and 1 1 genera are recognized. relacion a todos 10s gtneros except0 Oedipina, aunque Dendrotriton Th: genus Chiropterotriton is shown to be polyphyletic; thus, two es facilmente distinguible de Oedipina. Nototriton podria ser para- new genera are described. Nototriton new genus, includes the picadoi filt'tico en relacion a Oedipina, pero estos dos gtneros pueden ser group of Chiropterotriton beta. Dendrotriton new genus, includes the rapidamente reconocidos en base a sus marcadas diferencias en eco- hrc meliacia group of Chiropterotriton beta. Those species formerly logia y forma corporal. Pseudoeurycea comprende especies morfo- cal ed Chiropterotriton alpha remain as the sole representatives of Iogicamente generalizadas que podrian estar no muy alejadas de la the genus. Eight of the eleven neotropical genera are shown to be morfologia del grupo ancestral del ensamble neotropical analizado. monophyletic. Of the three exceptional genera, both Dendrotriton Solo Nyctanolis y Chiropterotriton son mas plesiom6rficos que Pseu- and Nototriton are nonparaphyletic relative to all genera except Oed- doeurycea. Listas de las especies asignadas a cada gtnero se presen- ipiaa. but Dendrotriton is easily distinguished from Oedipina. No- tan. Tambih se discuten las potenciales relaciones dentro del su- tot,iton may be paraphyletic relative to Oedipina, but the two genera pergknero Bolitoglossa, pero paralelismos y convergencias han sido car be readily distinguished on the basis of major differences in tan prevalentes que ninguna opinion definitiva puede plantearse en ecc logy and shape. Pseudoeurycea comprises morphologically gen- cuanto a afinidades genericas. eralized species that may not be far removed from the morphology off he ancestral stock ofthe entire neotropical group. Only Nyctanolis INTRODUCTION and Chiropterotriton are more plesiomorphic than Pseudoeurycea. Lists of species assigned to the genera are provided. Potential rela- In the summer of 1974, the junior author collected several tio iships within the supergenus Bolitoglossa are discussed, but par- species ofsalamanders in a remote area in northwestern Gua- alldism and convergence have been so extensive that no definitive temala. Included in this collection were three species that sta ement concerning generic affinities is possible. obviously were undescribed. Subsequent morphological analysis showed that two of the new species have combi- RESUMEN. Un nuevo gCnero y especie de salamandra plethodon- nations of traits that require them to be placed into two new tid.1 bolitoglossina se describe en base a material recolectado en el genera. One of these (Nyctanolis) has been described else- no1 oeste de Guatemala. Bradytriton silus, nuevo genero, nueva es- where (Elias and Wake, 1983). In this paper we describe the pec ie, es peculiar por su combinacion de caracteres que incluye una second new genus. We also report the results of a detailed col I comprimida lateralmente, un cuerpo macizo con cuello esca- sariente definido, y patas delgadas y cortas provistas de manos y pies syndactilos. Para diagnosticar este nuevo ghero se realizo un 1. Museum of Vertebrate Zoology and Department of Zoology, an: lisis del grupo completo de salamandras plethodontidas neotro- University of California, Berkeley, California 94720. picdes. Las aproximadamente 138 especies pertenecen al supergt- 2. Research Associate in Herpetology, Natural History Museum neio Bolitoglossa, en el cual se reconocen 1 I generos. El genero of Los Angeles County, Los Angeles, California 90007. Contributions in Science, Number 345, pp. 1-19 Natural History Museum of Los Angeles County, 1983 lSSll0459-8113 analysis of all of the currently recognized genera of tropical undescribed species, and a number of described species- salamanders. As a result of this analysis, which was a nec- including some crucially important ones-are known from essary background for the description of the new genera and only one or a very few individuals. Nevertheless, we believe species, two additional new genera are erected. These are that the broad outlines of relationship are sufficiently clear described herein, and diagnostic characters are given for all to justify the substantial revision we undertake here. existing genera of tropical salamanders. In addition, all rec- ognized species of tropical salamanders are referred to a ge- MATERIALS AND METHODS nus, and relationships among the genera are examined. This We have not considered in detail the species of Bolitoglossa, analysis reinforces previous views (Wake, 1966; Wake and Oedipina, and Thorius, all large, monophyletic genera, which Lynch, 1976) that there has been very extensive parallelism are either under intense study presently (Bolitoglossa by D.B. and convergence during the adaptive radiation of pletho- Wake, P. Alberch, A. Larson, and colleagues, Thorius by J. dontid salamanders in the New World tropics. Hanken), or have been analyzed recently (OedLpinaby Brame, 1968). Instead, we have emphasized apparently polyphyletic BACKGROUND and paraphyletic groups, as well as newly discovered species that do not easily fit into any existing genus. In these critical Although several genera of New World tropical salamander cases, we have analyzed doubly cleared and stained speci- species were described in the nineteenth century, and some mens, histological sections, and dissections of fixed material. knowledge of the diversity of the group was available at that As a point of departure for the choice and analysis of char- time, the most authoritative taxonomic work on these sal- acters, we have relied on the literature, which will be cited amanders during the early part ofthe twentieth century (Dunn, where appropriate. 1926) placed all tropical species in a single plethodontid ge- We have had access to adequate samples of most of the nus, Oedipus. Dunn considered Oedipus to be “a large, mod- species. Important species for which we have lacked sufficient ein genus of some 30 species. The extremes are quite different material but nevertheless can offer useful information include but there are many connecting links.” There was little in- (present generic designation used): Chiropterotriton barbouri, crease in knowledge of tropical salamanders until the mid- C. richardi, and Parvirnolge praecellens. These are discussed 1930’s, when Schmidt, Taylor, and other workers began pub- in appropriate places in the following account. lishing their results (for historical summary, see Wake, 1972, As noted above, one of the new genera has recently been and Smith and Smith, 1976). Taylor (1940) showed that described (Elias and Wake, 1983). We begin this work with Oedipus was a preoccupied name, and substituted the old an account of the characters that are used in our generic name Bolitoglossa for the entire assemblage, except for a revision. We then describe a newly discovered genus and group of diminutive species, which he placed in Cope’s (1 869) species and erect two new generic names to encompass pre- oid genus Thorius. Shortly thereafter, Taylor (1944) under- viously known species. Finally, we present a preliminary took a radical revision of all the neotropical salamanders, in phylogenetic analysis. which he described four new genera (Chiropterotriton, Par- vimolge, Magnadigita, Pseudoeurycea), resurrected Oedi- CHARACTERS USED FOR ANALYSIS pjna and Haptoglossa, and continued to recognize Bolito- g!ossa and Thorius. Since that time, there has been relative A necessary first step in the process of phylogenetic recon- stability in the generic classification of the group. Lineatriton struction is the identification of monophyletic taxa (sensu mas established by Tanner (1 950), Magnadigita was placed Eldredge and Cracraft, 1980). Our goal is to deduce mono- in the synonymy of Bolitoglossa by Wake and Brame (1 963), phyletic groups from a matrix of morphological character and Haptoglossa was placed in the synonymy of Oedipina states. There are incomplete data for too many species to by Brame (1968). The entire assemblage was characterized justify an extensive analysis at the species level. Accordingly, and the genera defined by Wake (1966), who established the we have relied on the literature and our own previous work supergenus Rolitoglossa for this group.