The Mohave Rattlesnake (Crotalus scutulatus) is a highly venomous pitviper inhabiting the arid interior deserts, grasslands, and savannas of western North America. Currently two subspecies are recognized: the Northern Mohave Rattlesnake (C. s. scutulatus) ranging from southern California to the southern Central Mexican Plateau, and the Huamantla Rattlesnake (C. s. salvini) from the region of Tlaxcala, Veracruz, and Puebla in south-central Mexico. Although recent studies have demonstrated extensive geographic variation in venom composition and cryptic genetic diversity in this species, no modern studies have focused on geographic variation in morphology. Here we analyzed a series of qualitative, meristic, and morphometric traits from 347 specimens of C. scutulatus and show that this species is phenotypically cohesive without discrete subgroups, and that morphology follows a continuous cline in primarily color pattern and meristic traits across the major axis of its expansive distribution. Interpreted in the context of previously published molecular evidence, our morphological analyses suggest that multiple episodes of isolation and secondary contact among metapopulations during the Pleistocene were sufficient to produce distinctive genetic populations, which have since experienced gene flow to produce clinal variation in phenotypes without discrete or diagnosable distinctions among these original populations. For taxonomic purposes, we recommend that C. scutulatus be retained as a single species, although it is possible that C. s. salvini, which is morphologically the most distinctive population, could represent a peripheral isolate in the initial stages of speciation.
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The sprightly little sphaerodactyl: Systematics and biogeography of the Puerto Rican dwarf geckos Sphaerodactylus (Gekkota, Sphaerodactylidae)
Studies of the Caribbean herpetofauna (amphibians and reptiles) have made significant contributions to our knowledge of evolutionary patterns and processes. A prerequisite for these studies are accurate taxonomies and robust phylogenetic hypotheses. One notable Caribbean radiation lacking such data are dwarf geckos of the genus Sphaerodactylus. Systematics of the Puerto Rican Sphaerodactylus have been turbulent since the initial species descriptions and no molecular phylogenies exist that include complete or near-complete taxon sampling. Here, we combine a multi-locus molecular phylogeny with extensive morphological information to investigate the current diversity of Sphaerodactylus geckos from the Puerto Rican Bank, with a large number of species from Hispaniola as an outgroup. In particular, we focus our efforts on resolving the taxonomy of the Sphaerodactylus macrolepis Günther species complex. We find S. macrolepis sensu lato (currently two nominal species with nine subspecies) is made up of at least four diagnosable species within two clades: (1) the sister species Sphaerodactylus macrolepis sensu stricto from the Virgin Islands (including St. Croix) and Culebra, and S. parvus King from islands in the northern Lesser Antilles; and (2) all other Sphaerodactylus macrolepis subspecies from Puerto Rico, Vieques, and Culebra. We resurrect Sphaerodactylus grandisquamis Stejneger from synonymy to refer to all subspecies from Puerto Rico and elevate the subspecies Sphaerodactylus inigoi Thomas & Schwartz for geckos from Vieques and western Culebra. The resulting phylogeny and revised taxonomy will be a useful tool for subsequent research into Sphaerodactylus conservation and evolution.
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- Award ID(s):
- 1657662
- NSF-PAR ID:
- 10149238
- Date Published:
- Journal Name:
- Zootaxa
- Volume:
- 4712
- Issue:
- 2
- ISSN:
- 1175-5326
- Page Range / eLocation ID:
- 151 to 201
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The butterfly tribe Candalidini is geographically restricted to Australia and mainland New Guinea and its adjacent islands. With 60 species and subspecies, it represents a large radiation of Papilionoidea in the Australian region. Although the species‐level taxonomy is relatively well understood, the number of genera is uncertain, varying from two to eight. We reconstructed the phylogeny of the Candalidini based on a 13‐locus hybrid enrichment probe set (12.8 Kbp: COI, Thiolase, CAD, CAT, DDC, EF1‐a, GAPDH, HCL, IDH, MDH, RPS2, RPS5, Wingless), including all previously recognized genera and 76% (28/37) of the species‐level diversity of the tribe. Maximum likelihood analysis recovered the Candalidini as a strongly supported monophyletic group. In conjunction with morphological characters, the phylogeny provided a robust framework for a revised classification in which we recognize four genera, 37 species and 23 subspecies. The genus
Nesolycaena Waterhouse & R.E. Turner is considered in synonymy withCandalides Hübner, and four other genera are not recognized, namely,Holochila C. Felder,Adaluma Tindale,Zetona Waterhouse andMicroscena Tite. Of the four valid genera, theabsimilis group (23 species) is placed in the newly described genusEirmocides Braby, Espeland & Müllergen. nov. (type speciesCandalides consimilis Waterhouse). Theerinus group (six species) is assigned toErina Swainson, which is reinstated.Chrysophanus cyprotus Olliff is assigned toCyprotides Tite, which is also reinstated as a monotypic genus. The remaining seven species are placed inCandalides sensu stricto . Overall, we propose 47 new nomenclatural changes at the species and subspecies levels, including the synonymy ofHolochila biaka Tite asEirmocides tringa biaka (Tite)syn. nov. et comb. nov. and recognition ofCandalides hyacinthinus gilesi M.R. Williams & Bollam as a distinct speciesErina gilesi (M.R. Williams & Bollamstat. rev. et comb. nov. A dated phylogeny using Bayesian inference in BEAST2 and biogeographical and habitat analyses based on the DEC model in BioGeoBEARS indicated that the ancestor of the Candalidini most likely evolved in rainforest habitats of the mesic biome in situ on the Australian plate of Southern Gondwana during the Eocene (c. 43 Ma). A major period of diversification occurred in the Miocene, which coincided with aridification of the Australian continent, followed by a further episode of radiation in montane New Guinea during the Plio‐Pleistocene.This published work has been registered on ZooBank by the authors: Michael Braby:
http://zoobank.org/urn:lsid:zoobank.org:author:4D3A7605‐EBD0‐40F6‐A5F2‐7F67F59E3D60 ;Marianne Espeland:
http://zoobank.org/urn:lsid:zoobank.org:author:00D6F9F9‐3902‐4A8B‐846F‐720AB32922A6 ;Chris Müller:
http://zoobank.org/urn:lsid:zoobank.org:author:15FE5F26‐7596‐46C2‐9697‐1FD92A692D0D ;http://zoobank.org/urn:lsid:zoobank.org:pub:47D5CA34‐C294‐4FBD‐84B6‐1C2A82B7CADF . -
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Abstract Since the first Spanish settlers brought horses to America centuries ago, several local varieties and breeds have been established in the New World. These were generally a consequence of the admixture of the different breeds arriving from Europe. In some instances, local horses have been selectively bred for specific traits, such as appearance, endurance, strength, and gait. We looked at the genetics of two breeds, the Puerto Rican Non-Purebred (PRNPB) (also known as the “Criollo”) horses and the Puerto Rican Paso Fino (PRPF), from the Caribbean Island of Puerto Rico. While it is reasonable to assume that there was a historic connection between the two, the genetic link between them has never been established. In our study, we started by looking at the genetic ancestry and diversity of current Puerto Rican horse populations using a 668 bp fragment of the mitochondrial DNA D-loop (HVR1) in 200 horses from 27 locations on the island. We then genotyped all 200 horses in our sample for the “gait-keeper”
DMRT3 mutant allele previously associated with the paso gait especially cherished in this island breed. We also genotyped a subset of 24 samples with the Illumina Neogen Equine Community genome-wide array (65,000 SNPs). This data was further combined with the publicly available PRPF genomes from other studies. Our analysis show an undeniable genetic connection between the two varieties in Puerto Rico, consistent with the hypothesis that PRNPB horses represent the descendants of the original genetic pool, a mix of horses imported from the Iberian Peninsula and elsewhere in Europe. Some of the original founders of PRNRB population must have carried the “gait-keeper”DMRT3 allele upon arrival to the island. From this admixture, the desired traits were selected by the local people over the span of centuries. We propose that the frequency of the mutant “gait-keeper” allele originally increased in the local horses due to the selection for the smooth ride and other characters, long before the PRPF breed was established. To support this hypothesis, we demonstrate that PRNPB horses, and not the purebred PRPF, carry a signature of selection in the genomic region containing theDMRT3 locus to this day. The lack of the detectable signature of selection associated with theDMRT3 in the PRPF would be expected if this native breed was originally derived from the genetic pool of PRNPB horses established earlier and most of the founders already had the mutant allele. Consequently, selection specific to PRPF later focused on allels in other genes (includingCHRM5, CYP2E1, MYH7, SRSF1, PAM, PRN and others) that have not been previously associated with the prized paso gait phenotype in Puerto Rico or anywhere else. -
Abstract Metacercariae of the genus Posthodiplostomum are often recorded in freshwater fish hosts. While the diversity and taxonomy of this genus are receiving increasing attention in molecular phylogenetic studies, available data remain geographically biased. Most molecular studies of Posthodiplostomum and morphologically similar (neascus) worms originate in North America and Europe and Asia (more than 60% of DNA sequences are from USA and Canada), with few data currently available from the Neotropics, where high host diversity suggests high and under-sampled parasite diversity. In this study, we report molecular and morphological data from metacercariae of Posthodiplostomum in fish in Puerto Rico, where only a single species has been previously reported. Partial sequences of cytochrome c oxidase subunit 1 from metacercariae from Dajaus monticola (native to Puerto Rico) and the introduced fishes Poecilia reticulata , Parachromis managuensis , Lepomis macrochirus and Micropterus salmoides revealed 7 genetically distinct species-level lineages, of which 4 were novel. We report novel molecular life-cycle linkages in Posthodiplostomum macrocotyle (metacercariae in muscle of the cichlid Pa. managuensis ), a species previously known only from adults in birds from South America; and in Posthodiplostomum sp. 23 (metacercariae in poeciliids), which has recently been found in Ardea herodias in Georgia, USA. We also report the first molecular data from Posthodiplostomum sp. 8 in M. salmoides in the Caribbean. Metacercariae of most species were morphologically distinguished and all displayed narrow specificity for fish hosts, with no indication of parasite sharing among introduced and native fishes.more » « less
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Premise The Caribbean islands are in the top five biodiversity hotspots on the planet; however, the biogeographic history of the seasonally dry tropical forest (SDTF) there is poorly studied.
Consolea consists of nine species of dioecious, hummingbird‐pollinated tree cacti endemic to the West Indies, which form a conspicuous element of the SDTF. Several species are threatened by anthropogenic disturbance, disease, sea‐level rise, and invasive species and are of conservation concern. However, no comprehensive phylogeny yet exists for the clade.Methods We reconstructed the phylogeny of
Consolea , sampling all species using plastomic data to determine relationships, understand the evolution of key morphological characters, and test their biogeographic history. We estimated divergence times to determine the role climate change may have played in shaping the current diversity of the clade.Results Consolea appears to have evolved very recently during the latter part of the Pleistocene on Cuba/Hispaniola likely from a South American ancestor and, from there, moved into the Bahamas, Jamaica, Puerto Rico, Florida, and the Lesser Antilles. The tree growth form is a synapomorphy ofConsolea and likely aided in the establishment and diversification of the clade.Conclusions Pleistocene aridification associated with glaciation likely played a role in shaping the current diversity of
Consolea , and insular gigantism may have been a key innovation leading to the success of these species to invade the often‐dense SDTF. This in‐situ Caribbean radiation provides a window into the generation of species diversity and the complexity of the SDTF community within the Antilles.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.11646/zootaxa.4712.2.1
