Search

El milpiés mexicano Euryurus flavocarinatus Daday, 1889, ha permanecido como incertae sedis por más de un siglo. El examen del holotipo demuestra que la especie pertenece al género Amplinus dentro de la amplia familia Aphelidesmidae, orden Polydesmida. En el presente trabajo presentamos una redescripción completa del holotipo de Amplinus flavocarinatus (Daday, 1889) comb. nov. Por otro lado, Euryurus flavocarinatus Silvestri, 1899 (actualmente cosiderada dentro del género Pycnotropis) es un homónimo primario más reciente de E. flavocarinatus Daday, 1889, por lo que proponemos el nombre Pycnotropis silvestrii Recuero & Aguado- Aranda nom. nov. para sustituir el nombre de Silvestri y resolver la homonimia.

nostraca are known by their ability for long-distance dispersal, but the existence in several spe-cies of deep, geographically structured mtDNA lineages suggests their populations are subjectedto allopatric differentiation, isolation, and prevalence of local scale dispersion.Tanymastix stagna-lisis one of the most widespread species of Anostraca and previous studies revealed an uncleargeographical pattern of mtDNA genetic diversity. Here, we analyze populations from the Iberianand Italian Peninsulas, Central Europe, and Scandinavia, with the aim to characterize the patternsof genetic diversity in a spatio-temporal framework using mtDNA and nuclear markers to test geneflow among close populations. For these aims we built a time-calibrated phylogeny and carried outBayesian phylogeographic analyses using a continuous diffusion model. Our results indicated thatT. stagnalispresents a deeply structured genetic diversity, including 7 ancient lineages, some ofthem even predating the Pleistocene. The Iberian Peninsula harbors high diversity of lineages, withstrong isolation and recent absence of gene flow between populations. Dispersal at local scaleseems to be the prevailing dispersal mode ofT. stagnalis, which exhibits a pattern of isolation-by-distance in the Iberian Peninsula. We remark the vulnerability of most of these lineages, giventhe limited known geographic distribution of some of them, and the high risk of losing importantevolutionary potential for the species., This work was supported by the Project Grant CGL2015-66571-P (MINECO/FEDER) of Spain.

Millipede diversity in tropical regions, and in Mexico in particular, is still mostly unknown. A modest but recurrent source of new Mexican species is the colonization of exotic species, due to human activity. The invasive speciesCylindrodesmus hirsutusPocock, 1889 has spread from its area of origin in Indonesia or Melanesia and become a virtually pantropical species. Although long known from South and Central America, reports from the Caribbean are sparse and limited to some eastern islands and southern Central America. On 9 March 2016, two adult specimens were found on Cozumel Island, Quintana Roo, in an area of medium semideciduous tropical forest. This paper comprises the first record of this species from Mexico and the northern Caribbean. Given the intense commercial activity in the region, the presence of more populations both in Cozumel Island and in the mainland coast is highly probable.

Este artículo contiene 11 páginas, 5 figuras, 1 tabla., Dolistenus Fanzago, 1874 is a widespread Mediterranean millipede genus of the order Platydesmida, currently including three valid species, each with relict distributions. Here we describe a fourth species of Dolistenus, and characterize it using morphological and molecular (mitochondrial DNA) characters. We provide an updated key to the species of Dolistenus and the first COI barcode sequences for the new species and several other European representatives of the Andrognathidae (Platydesmida).

Facultative or obligate paedomorphosis has evolved several times in Mexican populations of the salamander genus Ambystoma, leading to increased genetic divergence among populations with alternate life histories and contributing to population divergence in this species complex. In the present study, we surveyed the genetic diversity of Ambystoma populations in lakes of the Cuenca Oriental, a high elevation closed drainage basin that encompasses permanent crater lakes harbouring salamander populations. We genotyped individuals from five populations aiming to better understand population dynamics and the evolution of paedomorphosis in this system. Specifically, we tested the hypotheses that the evolution of paedomorphosis in Ambystoma taylori resulted in reduced genetic exchange with populations of Ambystoma velasci in neighbouring lakes. Second, we tested whether the populations in brackish lakes of the Cuenca Oriental, Lake Atexcac, and Lake Alchichica show restricted gene flow across the basin, possibly as a result of local adaptation to those microhabitats. Using various indices of population genetic diversity, Bayesian assignment, and approximate Bayesian computation methods, we show that genetic exchange between brackish lakes and freshwater lakes is negligible, despite continued gene flow among freshwater lakes. We show that the first divergence among populations occurred between Alchichica and the remaining populations and that the evolution of paedomorphosis in A. taylori was likely favoured by local adaptation to saline conditions, thus increasing its genetic isolation. An apparently similar process appears to be in progress independently in lake Atexcac, showing that local adaptation may play an important role in population isolation and, ultimately, in speciation.

Currently with 85 named species, the family Platyrhacidae in America is still poorly studied, particularly regarding Barydesmus Cook, 1896, the most diversified among the American genera. The center of diversification of Barydesmus lies in the northern third of the Andes Mountains, a megadiverse region where surely more species of these large, conspicuous diplopods await description. Here we present a new species, Barydesmus nangaritza sp. nov., easily diagnosable by the shape of the paranota, unique among the American Platyrhacidae. We provide also an updated bibliographical, annotated checklist of the whole family in America, with the aim of encouraging further studies in the group. The checklist includes the following new combinations under the genus Barydesmus: Barydesmus acanthopleurus (Hoffman, 1960) comb. nov., B. acanthosternus (Brölemann, 1900) comb. nov., B. acompus (Chamberlin, 1941) comb. nov., B. aequinoctius (Attems, 1914) comb. nov., B. affinis (Brölemann, 1919) comb. nov., B. andinus (Cook, 1896) comb. nov., B. azulae (Kraus, 1956) comb. nov., B. balsapuertus (Chamberlin, 1941) comb. nov., B. bifasciatus (Silvestri, 1897) comb. nov., B. bombonus (Chamberlin, 1941) comb. nov., B. broelemanni (Attems, 1914) comb. nov., B. brunnior (Chamberlin, 1941) comb. nov., B. celinus (Chamberlin, 1941) comb. nov., B. chuncho (Chamberlin, 1941) comb. nov., B. clathratus (Gervais, 1847) comb. nov., B. comptus Cook, 1896 comb. nov., B. contayus (Chamberlin, 1941) comb. nov., B. dunalii (Gervais, 1847) comb. nov., B. exsul (Cook, 1896) comb. nov., B. festae (Silvestri, 1897) comb. nov., B. fuscatus (Chamberlin, 1941) comb. nov., B. helophorus (Attems, 1899) comb. nov., B. incus (Chamberlin, 1941) comb. nov., B. javarynus (Schubart, 1950) comb. nov., B. leucus (Chamberlin, 1941) comb. nov., B. loretus (Chamberlin, 1941) comb. nov., B. manserichus (Chamberlin, 1941) comb. nov., B. medius (Chamberlin, 1941) comb. nov., B. obscurus (Kraus, 1955) comb. nov., B. orellanus (Chamberlin, 1941) comb. nov., B. pococki (Brölemann, 1911) comb. nov., B. retentus (Chamberlin, 1941) comb. nov., B. riparius (Carl, 1902) comb. nov., B. rufipes (Koch, 1847) comb. nov., B. scaber (Koch, 1847) comb. nov., B. socius (Chamberlin, 1941) comb. nov., B. strenuus (Silvestri, 1897) comb. nov., B. tambonus (Chamberlin, 1952) comb. nov., B. tapichus (Chamberlin, 1941) comb. nov., B. trichotypus (Chamberlin, 1941) comb. nov., B. utoquinius (Chamberlin, 1941) comb. nov. and B. zygethus (Chamberlin, 1941) comb. nov.

Author(s): Rovito, SM; Parra-Olea, G; Recuero, E; Wake, DB | Abstract: The Neotropical bolitoglossine salamanders represent an impressive adaptive radiation, comprising roughly 40% of global salamander species diversity. Despite decades of morphological studies and molecular work, a robust multilocus phylogenetic hypothesis based on DNA sequence data is lacking for the group. We estimated species trees based on multilocus nuclear and mitochondrial data for all major lineages within the bolitoglossines, and used our new phylogenetic hypothesis to test traditional biogeographical scenarios and hypotheses of morphological evolution in the group. In contrast to previous phylogenies, our results place all Central American endemic genera in a single clade and suggest that Central America played a critical role in the early biogeographical history of the group. The large, predominantly Mexican genus Pseudoeurycea is paraphyletic, and analyses of the nuclear data place two lineages of Pseudoeurycea as the sister group of Bolitoglossa. Our phylogeny reveals extensive homoplasy in morphological characters, which may be the result of truncation or alteration of a shared developmental trajectory. We used our phylogenetic results to revise the taxonomy of the genus Pseudoeurycea.

European tree frogs ( Hyla ) characterized by short temporal parameters of the advertisement call form six genetically differentiated but morphologically cryptic taxa, H. arborea sensu stricto, H. orientalis and H. molleri from across Europe to western Asia (together referred to as H. arborea sensu lato), two putative taxa within H. intermedia (Northern and Southern) from the Italian Peninsula and Sicily, and H. sarda from Sardinia and Corsica. Here, we assess species limits and phylogenetic relationships within these ‘short-call tree frogs’ based on mitochondrial DNA and nuclear protein-coding markers. The mitochondrial and nuclear genes show partly incongruent phylogeographic patterns, which point to a complex history of gene flow across taxa, particularly in the Balkans. To test the species limits in the short-call tree frogs and to infer the species tree, we used coalescent-based approaches. The monophyly of H. arborea sensu lato is supported by the mtDNA as well as by the all-gene species tree. The Northern and Southern lineages of H. intermedia have been connected by nuclear gene flow (despite their deep mtDNA divergence) and should be treated as conspecific. On the contrary, the parapatric taxa within H. arborea sensu lato should be considered distinct species ( H. arborea , H. orientalis , H. molleri ) based on the coalescent analysis, although signs of hybridization were detected between them ( H. arborea × H. orientalis ; H. arborea × H. molleri ). A mitochondrial capture upon secondary contact appears to explain the close mtDNA relationship between the geographically remote Iberian H. molleri and H. orientalis from around the Black Sea. Introgressive hybridization occurred also between the Balkan H. arborea and northern Italian H. intermedia , and between the Minor Asiatic H. orientalis and Arabian H. felixarabica (the latter belonging to a different acoustic group/clade). Our results shed light on the species limits in the European short-call tree frogs and show that introgression played an important role in the evolutionary history of the short-call tree frogs and occurred even between taxa supported as distinct species.

Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular interest regarding evolutionary potential. Even in well-studied regions such information is lacking for the majority of species, including many endemic species with reduced distribution ranges. We investigate the phylogeographic pattern of the Iberian frog Rana iberica, an endemic amphibian restricted to Central and North-Western Iberian Peninsula. Using mitochondrial sequences, we reconstruct the phylogeographic history of the species to test the effect of Quaternary climate changes on the evolutionary diversification of lineages, that is, the differentiation of mitochondrial lineages and the formation of genetic diversity melting pots, and integrate phylogeographic evidence for future conservation planning. Our results indicate the existence of 3 main mitochondrial lineages differentiated during the Upper Pleistocene. Both historical demographic analyses and climatic niche modeling show a strong effect of glacial climate changes, suggesting recurrent range contractions and expansions. Under such circumstances, differentiation took place most likely by isolation in allopatric interglacial refugia. Secondary lineage admixture in northern Portugal generated a broad mixed zone with highest nucleotide diversity. Given its particular evolutionary potential, its reduced distribution and eventual threats under current climate change scenario, conservation priorities should focus on the isolated lineage from Sierra de Guadalupe., This work was supported by the Portuguese Foundation for Science and Technology (FCT) through post doc grants (SFRH/BPD/27173/2006 to J.T.) and (SFRH/BPD/26555/2006 to H.G.). Currently, H.G. is supported by a postdoctoral Grant from FCT (SFRH/BPD/102966/2014). Additional support was provided from project CGL2015-66571-P by Spanish Ministerio de Economía y Competitividad (MINECO/FEDER).

El isópodo terrestre Armadillidium mateui Vandel, 1953 constituye un endemismo de la Península Ibérica poco común y prácticamente desconocido. La especie presenta una distribución fuertemente disyunta, con solo ocho registros publicados de tres regiones diferentes en el sureste, este y norte de España. Viendo este extraño patrón de distribución, la identidad de parte de la información publicada ha sido cuestionada. En este trabajo presentamos nuevos registros en la península ibérica y discutimos sobre la distribución conocida y potencial del isópodo endémico A. mateui, aparentemente mayor de lo previamente esperado.

The Common toad Bufo bufo sensu lato is a widespread, morphologically conserved taxon. Recent studies have uncovered deep genetic differentiation between population groups, highlighting the need to revise the current taxonomy of the group and recognize additional species. Here we investigate patterns of variation in molecular (a mitochondrial DNA restriction enzyme assay and sequence data for two nuclear DNA fragments totalling 979 bp) and 17 morphological variables in Northern France where two of these groups meet (B. bufo sensu stricto and B. spinosus), in order to delineate their contact zone and uncover characters that would allow discrimination of the two taxa. Mitochondrial DNA data show an abrupt transition from areas where B. bufo is present to those inhabited by B. spinosus, with a narrow area of overlap east of the city of Caen. Morphometric characters, particularly those related to the positioning of the parotoid glands and metatarsal tubercle shape and size, proved useful in discriminating between species (AUC ≥ 0.97, kappa ≥ 0.79). We then used the differentiating character states to allocate over 300 museum specimens from Western Europe to either species with consistent results, including comparable values of AUC and kappa of the identification models, indicating that models could successfully be applied across datasets. We summarize available evidence relevant to the delineation of the distribution of B. bufo and B. spinosus in France and discuss the characters differentiating both species in an evolutionary context. In view of the observed morphological and genetic differentiation and the absence of unequivocal evidence for widespread hybridization we support the view that B. bufo and B. spinosus are best considered different species. Finally, we propose that ‘parotoids in parallel position’ and a thin and smooth skin are derived character states for B. bufo over the northern part of its range.

We investigated the recent evolutionary history of the Danube crested newt, Triturus dobrogicus through reconstructions of: (1) the number and position of refugia at the last glacial maximum, (2) the role of major central European rivers in pattern of post-glacial dispersal, and (3) the present-day distribution pattern. We analysed sequences of mitochondrial DNA (ND2, 1065 bp) and six microsatellite loci in 363 T. dobrogicus individuals from 58 populations covering the range of the species. Our analyses suggested that T. dobrogicus survived the last glacial maximum in two separate refugia positioned in northwestern Pannonia and in Southern Pannonia from where its range expanded along the Danube and Tisza Rivers. Our findings also confirmed that rivers played an important role in shaping the evolutionary history of amphibian species in Central Europe. We compared the T. dobrogicus range with another lowland amphibian, the fire-bellied toad Bombina bombina, using species distribution modelling. In line with these models, the isolated mountains inside Pannonia are occupied not by B. bombina, but by its mountain-dwelling sister-species B. variegata. However, in contrast to the model, crested newts (including T. dobrogicus) are absent from these mountains. We attribute this biogeographical discrepancy to the positioning of the species’ refugia at the last glacial maximum., JV was supported by the project Faunagenezis of the National Office for Research and Technology, Hungary (NKFP 3B-02304), the Hungarian Scientific Research Fund (OTKA K84071), and the Bolyai János Research Scholarship of the Hungarian Academy of Sciences. ER was supported by a DGAPA-UNAM postdoctoral fellowship. A research permit was provided by the Ministry of Environment and Water, Hungary (KJHF-848/3/2005).

The Pleistocene was characterized by climatic changes that greatly altered the distribution of organisms. Population extinctions, bottlenecks, isolation, range expansions and contractions were often associated with glaciations, leaving signatures in the spatial patterns of genetic diversity across species. Lissotriton helveticus belongs to a Pan-European lineage of newts that were strongly affected by glaciations and represent an excellent model to analyse the effect of generalized climatic changes in phylogeographic patterns. We studied the genetic diversity of the species using data from two mitochondrial and three nuclear genes analyzed in a Bayesian phylogenetic framework to investigate the historical processes shaping spatial patterns of genetic diversity. Mitochondrial haplotypes cluster in four different groups present in the Iberian Peninsula and of Pleistocene origin, probably by allopatric fragmentation. Nuclear genes present no obvious geographic structure patterns, suggesting gene flow and generalized incomplete lineage sorting. Populations north of the Pyrenees are closely related to those from northeastern Iberia, suggesting recent range expansion from this region. Historical demographic analyses indicate a demographic expansion starting about 100,000 years ago and more recent population declines. Compared to other Lissotriton species, L. helveticus includes only relatively young genetic lineages, suggesting a Central European pre-Pleistocene distribution followed by complete extirpation of the species during glaciations in that area. Historical demographic trends in the Iberian Peninsula are reversed with respect to the more Mediterranean species Lissotriton boscai , indicating different responses of both species to climate changes. Diversity patterns among Lissotriton species seem to be defined by four main factors: ancestral distributions, colonization capabilities, interactions with other species and effective population sizes. Differences in these factors define two types of species, referred to as “R” (refugia) and “S” (sanctuaries) that explain part of the diversity in patterns of genetic diversity created by glaciations in Western Europe.

13 páginas, 3 figuras, 2 tables et al.., Aim To study the patterns of genetic variation and the historical events and processes that influenced the distribution and intraspecific diversity in Hyla meridionalis Boettger, 1874. Location Hyla meridionalis is restricted to the western part of the Mediterranean region. In northern Africa it is present in Tunisia, Algeria and Morocco. In southwestern Europe it is found in the south of France, north-western Italy and northeastern and south-western Iberian Peninsula. There are also insular populations, as in the Canaries and Menorca. Methods Sampling included 112 individuals from 36 populations covering the range of the species. We used sequences of mitochondrial DNA Cytochrome Oxidase I (COI) for the phylogeographical analysis (841 bp) and COI plus a fragment including part of tRNA lysine, ATP synthase subunits 6 and 8 and part of Cytochrome Oxidase III for phylogenetic analyses (2441 bp). Phylogenetic analyses were performed with paup*4.0b10 (maximum likelihood, maximum parsimony) and MrBayes 3.0 (Bayesian analysis). Nested clade analysis was performed using tcs 1.18 and GeoDis 2.2. A dispersal-vicariant analysis was performed with diva 1.0 to generate hypotheses about the geographical distribution of ancestors. Results We found little genetic diversity within samples from Morocco, southwestern Europe and the Canary Islands, with three well-differentiated clades. One is distributed in south-western Iberia and the High Atlas, Anti-Atlas and Massa River in Morocco. The second is restricted to the Medium Atlas Mountains. The third one is present in northern Morocco, north-eastern Iberia, southern France and the Canaries. These three groups are also represented in the nested clade analysis. Sequences from Tunisian specimens are highly divergent from sequences of all other populations, suggesting that the split between the two lineages is ancient. diva analysis suggests that the ancestral distribution of the different lineages was restricted to Africa, and that an explanation of current distribution of the species requires three different dispersal events. Main conclusions Our results support the idea of a very recent colonization of south-western Europe and the Canary Islands from Morocco. South-western Europe has been colonized at least twice: once from northern Morocco probably to the Mediterranean coast of France and once from the western coast of Morocco to southern Iberia. Human transport is a likely explanation for at least one of these events. Within Morocco, the pattern of diversity is consistent with a model of mountain refugia during hyperarid periods within the Pleistocene. Evaluation of the phylogenetic relationships of Tunisian haplotypes will require an approach involving the other related hylid taxa in the area., Support during part of the development of this project for A.I. was provided by an Aranzadi fellowship and for E.R. by an I3P grant of the CSIC.

Widespread species with morphologically and ecologically differentiated populations are key to understand speciation because they allow investigating the different stages of the continuous process of population divergence. The alpine newt, Ichthyosaura alpestris, with a range that covers a large part of Central Europe as well as isolated regions in all three European Mediterranean peninsulas, and with strong ecological and life-history differences among populations, is an excellent system for such studies. We sampled individuals across most of the range of the species, and analyzed mitochondrial (1442 bp) and nuclear (two nuclear genes -1554 bp- and 35 allozyme loci) markers to produce a time-calibrated phylogeny and reconstruct the historical biogeography of the species. Phylogenetic analyses of mtDNA data produced a fully resolved topology, with an endemic, Balkan clade (Vlasina) which is sister to a clade comprising an eastern and a western group. Within the former, one clade (subspecies I. a. veluchiensis) is sister to a clade containing subspecies I. a. montenegrina and I. a. serdara as well as samples from southern Romania, Bosnia-Herzegovina, Serbia and Bulgaria (subspecies I. a. reiseri and part of I. a. alpestris). Within the western group, populations from the Italian peninsula (subspecies I. a. apuana and I. a. inexpectata) are sister to a clade containing samples from the Iberian Peninsula (subspecies I. a. cyreni) and the remainder of the samples from subspecies I. a. alpestris (populations from Hungary, Austria, Poland, France, Germany and the larger part of Romania). Results of (∗)BEAST analyses on a combined mtDNA and nDNA dataset consistently recovered with high statistical support four lineages with unresolved inter-relationships: (1) subspecies I. a. veluchiensis; (2) subspecies I. a. apuana+I. a. inexpectata; (3) subspecies I. a. cyreni+part of subspecies I. a. alpestris (the westernmost populations, plus most Romanian populations); and (4) the remaining populations, including subspecies I. a. serdara, I. a. reiseri and I. a. montenegrina and part of subspecies I. a. alpestris, plus samples from Vlasina. Our time estimates are consistent with ages based on the fossil record and suggest a widespread distribution for the I. alpestris ancestor, with the split of the major eastern and western lineages during the Miocene, in the Tortonian. Our study provides a solid, comprehensive background on the evolutionary history of the species based on the most complete combined (mtDNA+nDNA+allozymes) dataset to date. The combination of the historical perspective provided by coalescent-based analyses of mitochondrial and nuclear DNA variation with individual-based multilocus assignment methods based on multiple nuclear markers (allozymes) also allowed identification of instances of discordance across markers that highlight the complexity and dynamism of past and ongoing evolutionary processes in the species.

Species delineation remains one of the most challenging tasks in the study of biodiversity, mostly owing to the application of different species concepts, which results in contrasting taxonomic arrangements. This has important practical consequences, since species are basic units in fields like ecology and conservation biology. We here review molecular genetic evidence relevant to the systematics of toads in the Bufo bufo species group (Anura, Bufonidae). Two studies recently published in this journal (Recuero et al., MPE 62: 71-86 and García-Porta et al., MPE 63: 113-130) addressed this issue but reached opposing conclusions on the taxonomy of the group (four versus two species). In particular, allozyme data in the latter paper were interpreted as evidence for hybridization across species (between B. bufo-B. spinosus and B. bufo-B. verrucosissimus). We tested claims for hybridization through re-analysis of allozyme data for individuals instead of populations, to be able to distinguish between sympatry with and without admixture, and found no evidence of hybridization across taxa. We propose alternative explanations for the observed patterns that García-Porta et al. (2012) failed to consider. In the absence of unequivocal evidence for hybridization and introgression, we reject the proposal to downgrade Bufo spinosus and Bufo verrucosissimus to the subspecies level., IMS is a "Ramón y Cajal" postdoctoral fellow supported by the Spanish Ministerio de Ciencia e Innovación and the Universidad de Castilla la Mancha. Partial funds for this work were provided by grants CGL2008-04271-C02-01/BOS and CGL2011-28300 (Ministerio de Ciencia e Innovación, Ministerio de Economía y Competitividad, FEDER) and PPII10-0097-4200 (Junta de Comunidades de Castilla la Mancha) to IMS.

12 páginas, 5 figuras y 2 tables.., The Baja California populations of Pseudacris regilla, a widespread species in Western North America ranging from British Columbia to southern Baja California, are characterized by extensive geographic fragmentation. We performed phylogeographic and historical demographic analyses on 609 bp of the cytochrome b mitochondrial gene of 110 individuals representing 28 populations to determine the relative influences of current and historical processes in shaping the present distribution of genetic diversity on the Baja California Peninsula. Haplotypes from this area were nested in a clade with three well-differentiated groups. Two of these groups are from Baja California Sur and another is from California and Baja California. The estimated date for the split of these groups, between 0.9–1 Ma, fits with previously proposed hypotheses of vicariance due to diVerent transpeninsular seaways, although successive population fragmentation and expansion due to climatic oscillations during Pleistocene glaciations cannot be discarded. Historical demographic analyses detected signs of past population expansions, especially in the southernmost group. With respect to populations north of this region, two older clades were identified, one with haplotypes mainly distributed in central California, and the other corresponding to the northern half of the species range, in what apparently is a recurrent pattern in the Pacific coast of North America. Based on the concordance between mt-DNA and available allozyme data indicating that these species have a long independent evolutionary history, we propose to consider the three major clades as distinct species: P. regilla, P. pacifica, and P. hypochondriaca., We thank D. Buckley, S. Crews, and A. Leaché for helpful comments on the manuscript. Thanks to the Museum of Vertebrate Zoology, University of California, Berkeley for samples from the Tissue Collection. E.R. is sponsored by a fellowship CSIC-postgrado (Ref.: I3P-BPG2004) and I.M.-S. is funded by a postdoctoral Grant from the Spanish Ministerio de Educación y Ciencia (Ref. EX2004-0921). SEMARNAT provided collecting permits. Studies were financed in part by the Grants UC_Mexus-Conacyt CN-02-74 and PAPIIT-UNAM No. IN226605 to G.P.-O. and by a travel grant (“Marina Bueno”) to I.M.-S. This research has also benefited upon the resources provided by the Grant CGL2004-04680- C10-10/BOS (Ministerio de Educación y Ciencia, Spain).

The genus Myrmecodesmus was created by Silvestri (1910) to accommodate a small, myrmecophilous polydesmid from central Veracruz. It includes mainly fossorial species and several forms have been collected in caves or associated with ant nests (Silvestri 1911; Shear 1977). Silvestri (1911) described a second species in this genus from the same locality. During subsequent decades several new genera were created as new pyrgodesmid species were described from Mexico, but Myrmecodesmus included only two species until Hoffman (1973) proposed a synonymy with Ilyma Chamberlin, 1941, increasing to seven the number of species referable to Myrmecodesmus . By this time the characters traditionally used to define genera in this family (mostly pore presence and distribution, presence of ozophores, number of segments and ornamentation) started to be questioned (Hoffman 1973; Shear 1973). Finally, a partial taxonomic revision of Pyrgodesmidae from Mexico (Shear 1977) drastically simplified the generic composition of this family and up to 11 genera were introduced into the synonymy of Myrmecodesmus . Including the new combinations, Shear (1977) listed a total of 25 species under this genus, but he missed including a few. This was partly corrected by Hoffman (1999), raising the number to 28 species. However, both authors missed an additional species that implies some nomenclatural issues.