A new species of the Eleutherodactylus nigrovittatus Group is described from five localities, at elevations of 1800-2760 m in cloud forests in the Cordillera Oriental in central Peru (Distrito de Paucartambo, Departamento de Pasco). The new species is assigned to the Eleutherodactylus nigrovittatus Group, and differs from all described species therein by having a combination of smooth skin on the venter, undilated discs on the digits, Finger I and Finger II of variable length (slightly shorter, slightly longer or of equal length), Toe III and Toe V of variable length (slightly shorter, slightly longer or of equal length), and a snout-vent length up to 48.8 mm in females. In life, dorsum is tan with dark brown blotches, venter flesh to pale gray with small gray blotches, and posterior surfaces of thighs tan. The new species occurs sympatrically with E. lacrimosus, E. peruvianus, E. platydactylus, and Eleutheodactylus cf. rhabdolaemus. Phrynopus lucida and P. nebulanastes are changed to Eleutherodactylus based on morphological and osteological characters and are assigned to the Eleutherodactylus nigrovittatus Group.
We conducted a 13-yr study of Crotalus pricei in Arizona's Chiricahua Mountains, capturing 306 individual snakes and recapturing snakes on 155 occasions. Juveniles shed and fed more frequently and grew more quickly than adults. Spiny lizard (Sceloporus) scales were found in 78% of fecal samples, making Sceloporus the most common prey item for both juveniles and adults. Males became larger than females at 5 yr of age, a year or two after females reached reproductive size. Although 45% of adult females were gravid, reproduction was not typically biennial and larger snakes were more likely to be gravid than smaller adult snakes. Survival rate (mean ± SE) at our most-studied site was 0.707 ± 0.0334 and detectability was 0.309 ± 0.0386; detectability was positively correlated with number of search hours and negatively correlated with dry weather. Mean population size at this site was 67 snakes, and there was no evidence of a population decline over the course of the study. However, age class structure was skewed toward younger snakes at the site, probably due to illegal collection of snakes for the pet trade.
Toads of the genus Melanophryniscus are known since the mid-late 19th Century, and the first skeletal description was made early in 1875. However, it was not until the 1970s that osteological variation was discussed in a more inclusive taxonomic scenario. Derived from this, the first morphological synapomorphies proposed for the genus represented skeletal traits extracted from the few species considered in those studies. In this work, we examined the skeletons of 25 of the 29 currently recognized species of Melanophryniscus, plus three species under description, to examine their osteological variation and discuss the validity of those synapomorphic characters proposed, not only by analyzing their distribution within the genus but also by comparing them with the skeletal data available in the bibliography for other early branching bufonids. Our results show that main variations within the genus are related to changes in absolute body size and some proportions of postcranial elements. Except for M. setiba, an early diverging species that exhibits a number of autapomorphies, most skeletal traits are quite conserved throughout the genus. Members of the Melanophryniscus tumifrons group are distinctive by their nasal region, which tends to be taller than in other species, dome-shaped, and strongly exostosed. Most features considered diagnostic of the genus occur in other early branching bufonids, and are highly polymorphic, and this challenges earlier discussions on putative synapomorphies. For instance, exostosed frontoparietals only occur in M. setiba and M. klappenbachi, and the condition was also recorded for Osornophryne. The frontoparietal fontanelle, if present, may show different shapes and sizes (often similar to those in Osornophryne and some species of Atelopus). The zygomatic ramus of the squamosal may be absent or present as a small process, as described for some species of Atelopus, Osornophryne, and Truebella. Finally, posterolateral processes of the hyoid were observed in some early diverging species and hence we propose an alternative interpretation on its presence and distribution in the genus.
Chironius bicarinatus is a conspicuous colubrid snake species, widely distributed in northeastern, southeastern, central-western,
and southern Brazil, as well as Paraguay, Argentina, and Uruguay. On the basis of new morphological data of individuals from previously
unsampled regions and deoxyribonucleic acid sequences, we reviewed the taxonomy of populations previously referred to as C. bicarinatus, revisiting the species definition with an updated diagnosis, inferring its phylogenetic relationships with closely related lineages in southern Brazil,
herein described as a new species restricted to Pampa forests or grasslands and Atlantic Forest semidecidual forests in southern Brazil. The new species can be readily diagnosed from C. bicarinatus and all other congeners on the basis of internal (hemipenis unilobed, unicalyculate, cylindrical, apex with smooth calyces, with spinules restricted to proximal portion, near the medial area; lacrimal foramen with small projection on the anteroventral margin) and external morphology (ventrals 153–165 [153–165 in males, 155–164 in females]; subcaudals 103–146 pairs [129–142 in males, 103–146 in females]; adult dorsal pattern with dark green background, scales sometimes with light blue margin, two conspicuous black dorsal stripes with light green vertebral stripe between them that gradually dissipates to the tail, ventrals with black margin on its edges) and
The Eurycea quadridigitata complex is currently composed of the nominate species and E. chamberlaini, with no other species recognized. However, recent molecular studies have revealed at least five genetic lineages within this species complex, with one lineage more closely related to the neotenic Eurycea species of central Texas and E. chamberlaini nested within E. quadridigitata sensu lato. We use large-scale geographic sampling in combination with a multilocus species delineation method and morphology to test whether these genetic lineages represent distinct species under the general lineage concept of species. We describe two new species of salamander from this complex, resurrect and elevate a former subspecies to full species status, add to the diagnosis of E. chamberlaini, and redefine E. quadridigitata in the context of this revision. All five species are diagnosable from one another through a number of meristic, morphometric, molecular, and ecological criteria.
The Black-tailed Rattlesnake (Crotalus molossus Baird and Girard, 1853) is a wide-ranging species complex with representatives from the southwestern United States through the highlands of central and southern Mexico. The systematics of this group has received little attention and in the past six decades only two taxonomic changes have been proposed (the transfer of C. basiliscus oaxacus to C. molossus and the elevation of C. m. estebanensis to full species). However, a recent revision of the Neotropical Rattlesnakes (C. durissus and C. simus) recovered a polyphyletic C. molossus. We sequenced data from three mitochondrial genes (ATPases 8 and 6, cyt b, and ND4) and three nuclear genes (c-mos, EXPH5, and RAG1) to examine phylogenetic relationships among C. molossus lineages and the closely related species C. basiliscus and C. totonacus. Results recovered strong support for two deeply divergent northern C. molossus lineages that are morphologically distinct. Biogeographical patterns and divergence dates inferred from mitochondrial data suggest the diversification of C. molossus is the result of a Neogene vicariance event associated with uplift of the Sierra Madre Occidental. Population-level analyses suggest that major lineages of C. molossus have been stable since their initial divergence. On the basis of morphological and molecular evidence we resurrect the name Crotalus ornatus Hallowell, 1854 for Black-tailed Rattlesnake populations in the Chihuahuan Desert and central Texas, USA.
We reassessed the taxonomic status of the xenodontine snake Erythrolamprus bizona Jan (1863) based on a comprehensive review of literature records and comparative material. Our data demonstrate that the original diagnosis does not allow the unambiguous attribution of the name E. bizona to any population of the genus. After a thorough investigation in European institutions, we recovered two syntypes of the E. bizona type-series, confirming its composite nature. To circumvent the problem, we herein designate a lectotype for the species, providing a reformulated diagnosis and a detailed redescription. The lectotype represents one of the rare remaining specimens used in Giorgio Jan's original descriptions during the second half of 19th century, and is housed in the Museo Civico di Storia Naturale di Milano, Milan, Italy. For more than seven decades, herpetologists have assumed that such material had been lost forever due to bombings of World War II. Nonetheless, our finding corroborates recent studies demonstrating that at least some of Jan's snake types still exist for taxonomic research. Finally, we discuss the geographic congruence of the frequency distributions of segmental counts under an integrative approach aiming to maintain nomenclatural stability without ignoring preliminary evidence of taxonomic diversity.
The species of the subfamily Uromastycinae are herbivorous burrowing lizards distributed from the African Sahara Desert to the Asian Thar Desert and across the Arabian Peninsula. Although osteological studies on Uromastycinae have a long history, a detailed description of the complete skeleton is lacking. We investigate the cranial and postcranial osteology of the Mesopotamian Spiny-tailed Lizard (Saara loricata, previously referred to Uromastyx). We studied articulated and disarticulated materials from five specimens and present a complete description of the bones of the species. Our study adds to the growing body of literature on the skeleton of agamid lizards. Unlike Uromastyx sensu stricto, in S. loricata no anterior premaxillary foramina exists on the anterior surface of the premaxilla, no contact exists between the frontal and the maxilla or premaxilla, the anterolateral processes of the frontal are unexposed in dorsal view so that the prefrontal and nasal are attached, and the pterygoid does not contact the vomer anteriorly and the quadrate posteriorly. Unlike its congener S. hardwickii, in S. loricata no anterior premaxillary foramen exists on the anterior surface of the premaxilla, a smaller ethmoidal foramen perforates the nasal, a well-developed, posteriorly extended socket-like notch is formed through anterior bifurcation of the jugal, an L-shaped suture line forms between the jugal and postorbital in dorsal view, and an interlocking suture between the surangular and dentary exists in S. loricata.
With a published multilocus phylogenetic analysis as our guide, we use new data from the external phenotype and genetically defined distributions of evolutionary lineages to resolve species boundaries associated with the southwest Mindanao Stream Frogs, Sanguirana everetti (Boulenger 1882), its junior synonym, Rana mearnsi, Stejneger 1905, and the northeast Mindanao Stream Frogs, Sanguirana albotuberculata (Inger 1954). Consideration of relationships, distributions, type localities, phenotypic data, and type specimens clearly indicates that the names R. mearnsi and S. albotuberculata refer to the same lineage, and we recognize the oldest available name (Sanguirana mearnsi) for this species. We also define the central Philippine lineage (from Negros, Masbate, and Panay islands) as a distinct new species. Long confused with S. everetti, the new taxon is readily diagnosed and biogeographically restricted to the West Visayan faunal region. The new multilocus estimate of phylogeny and our multivariate analysis of morphological variation demonstrate that the new species is closely related and phenotypically most similar to northern Philippine Sanguirana luzonensis, to the exclusion of S. everetti, the southern species with which it previously was confused. Morphological characters distinguishing the new species include body size, the absence of infracloacal tubercles, the presence of smooth dorsal skin without dorsolateral folds or dermal asperities, its degree of sexual size dimorphism, uniquely stratified flank coloration, bright white subarticular tubercles, bold pectoral patches, dark transverse bars on the limbs, and various body proportions. Recognition of this new species further emphasizes the predictable nature of island bank-structured endemism in the Philippines and demonstrates that the country's vertebrate diversity remains underestimated. The new species is relatively rare, patchily distributed and, with so little natural forest remaining in the central Philippines, it constitutes an immediate conservation concern. Management of this problem will require continued, field-based collection of data on the new species, distribution, local abundance, population trends, natural history, reproductive biology, and larval ecology-most of which currently is unknown.
We infer species relationships within Lynchius, a frog genus with four species distributed along the paramos and cloud forests of the Andes of northern Peru and southern Ecuador, and assess species diversity in light of comparative analyses of anatomical traits and inferred relationships. Phylogenetic analyses rely on ~7000 base pairs of mtDNA and nuDNA sequences aligned using similarity-Alignment and tree-Alignment and optimized under maximum likelihood and parsimony criteria. Inferred relationships place Lynchius as the sister group of the widespread genus Oreobates and this clade as the sister group of the high Andean genus Phrynopus. Our analyses corroborate the dissimilar species Lynchius simmonsi as part of this clade and place it as the sister group of the remaining species of Lynchius. Parsimony and maximum likelihood analyses differ in the internal relationships of Lynchius with respect to the placement of L. flavomaculatus, L. nebulanastes, and L. parkeri, but support the existence of two unnamed species. External morphological comparisons provide diagnostic characters for the two new species, which are named and described herein. Lynchius tabaconas is sister to L. flavomaculatus and occurs at ~2800 m in the cloud forests of Santuario Nacional Tabaconas-Namballe, Cajamarca, Peru. Lynchius oblitus occurs in the same area but at a higher elevation (~3300 m) and is sister to a clade formed by L. flavomaculatus and L.Tabaconas in parsimony analyses and to L. nebulanastes in maximum likelihood analyses. We provide a new diagnosis for each of the six species and for the genus, as well as some natural history notes.
Hatchling emergence patterns were studied in a community of six species of freshwater turtles in Lancaster County, Pennsylvania, USA, including: Chelydra serpentina, Chrysemys picta, Clemmys guttata, Glyptemys insculpta, Glyptemys muhlenbergii, and Sternotherus odoratus. Data were collected every year from 1965–1985 on estimated date of emergence, carapace length, April–May precipitation, August–September precipitation, annual precipitation, and low temperature and occurrence of precipitation during the 24 h prior to the time of each hatchling detection (n = 806). Chelydra serpentina, Ch. picta, and Cl. guttata hatchlings have a facultative delayed emergence strategy. The other species (G. insculpta, G. muhlenbergii, and S. odoratus) appear to be obligate early emergers, with the exception of one hatchling G. muhlenbergii that delayed emergence. Early emergence occurred in some species every year. However, the majority of hatchlings delayed emergence until the year following oviposition, except in 1973, the year following intense flooding and nest destruction associated with a major hurricane. Mean estimated calendar day of emergence varied annually in C. serpentina and Ch. picta. The same variable also differed among species for comparisons of both early and delayed emergence. Chelydra serpentina hatchlings emerged earlier than all other species whether they used an early or delayed strategy. Carapace length of Ch. picta hatchlings varied significantly among years, and C. serpentina hatchlings that delayed emergence were significantly larger in carapace length than those that emerged early. Seasonal and previous 24-h precipitation had varying effects on the number of emerging hatchlings, but August–September precipitation in one year had a strong correlation with the number of hatchlings that delayed emergence until the following spring. The number of hatchlings detected peaked at a previous 24-h air temperature of about 12°C for both early and late emergence. Small species like G. muhlenbergii and S. odoratus may emerge early to limit potential hatchling competition in diverse communities of freshwater turtles with primarily delayed emergence.
We review morphology and systematics of Phoxophrys using new specimens of previously rare species. In addition to external characters, we relied heavily on skull morphology visualized using computed tomography data of all currently recognized species in this genus. Phylogenetic analysis of ND4, 12S, and 16S mDNA sequences reveal that Ph. tuberculatais sister to a clade containing Dendragama, Lophocalotes, and insular Pseudocalotes. Phoxophrys tuberculatais only distantly related to Bornean congeners. Phylogenetic analysis of 29 morphological characters scored for all the species of Phoxophry sand a diverse set of 22 outgroup taxa found four well-supported lineages: Ph. tuberculata, a clade of all Bornean congeners, Ph. nigrilabris, and a clade of the four large Bornean species. To resolve paraphyly of Phoxophrys, we revalidate Pelturagonia Mocquard for all Bornean species of this genus. As redefined, Phoxophrys contains a single species: Ph. tuberculata of Sumatra. We describe a new species of Pelturagonia from the Meratus Range of southeastern Kalimantan. The new species is the sister species of Pe. spiniceps. Like that species, it differs from congeners in having large, dorsally projecting scales between the dorsolateral caudal crests and apostorbital process of the frontal bone reaching the postciliary ornament.
Corrected relative abundance patterns demonstrated an extensive area of loggerhead Caretta caretta distribution from near Long Island, New York, along the mid-shelf to near Cape Hatteras, North Carolina. Areas of high relative abundance of leatherbacks Dermochelys coriacea were more scattered, with clusters south of Long Island and in the C and E Gulf of Maine. Loggerheads occurred significantly farther south than leatherbacks, and in significantly warmer waters (mean surface temperatures of 22.2°C and 20.4°C, respectively). The two species did not differ significantly in water depth or bottom slopes at sighting; the modal depth interval for both was 21-40 m. Absolute density estimates ranged from 1.64 × 10-3 to 5.10 × 10-1 loggerheads km-2 and 2.09 × 10-3 to 2.16 × 10-2 leatherbacks km-2. Total study area populations during the summer were estimated at 2200-11 000 loggerheads and 100-900 leatherbacks. These estimates are minimal because they are based on observations of turtles at the surface. -from Authors
The behavior of 10 free-ranging male green anoles A. carolinensis was videotaped in a riparian habitat. Comparisons of breeding versus non-breeding seasons showed dramatic shifts in the percentage of time spent in the various behavioral modes. Over all contexts, the respective breeding versus post-breeding season rates for distance moved and displaying were 26 m/h versus 8 m/h and 100 displays/h versus 6 displays/h. Breeding males were polygynous and defended exclusive, closely monitored home ranges that overlapped an average of 2.8 resident females. Males used all available microhabitats and were considered perch generalists. Males exhibited a wide range of foraging behaviour, reflecting a generalist's mode of prey capture. Males were bright green 75% (breeding season) and 87% (post-breeding season) of the time. Based on the results, the influence of captivity on lizard behaviour is discussed. -from Authors
Jackson's Forest Lizard (Adolfus jacksoni) is widespread throughout the highlands of the Albertine Rift, southern Uganda, western and central Kenya, and northern Tanzania. To understand the population genetics and phylogenetic relationships of this widespread taxon, we sequenced two mitochondrial (16S and cyt b) and two nuclear (c-mos and RAG1) genes from multiple populations. Population genetics analyses suggested a high degree of genetic differentiation among A. jacksoni populations, reflecting the high-elevation montane "islands" that they inhabit. Populations connected by a network of mountain ranges generally showed lower levels of genetic partitioning than those isolated by low-elevation habitat. Results from phylogenetic analyses and additional morphological data indicated that Adolfus jacksoni occurs throughout the Albertine Rift, likely from the Kabobo Plateau to the Lendu Plateau of Democratic Republic of the Congo, as well as southern Uganda, Mt. Elgon, and the highlands of western Kenya on the western side of the Kenyan Rift. Adolfus kibonotensis is removed from the synonymy of the latter taxon, elevated to full species, and recognized from the central Kenyan highlands to northern Tanzania on the eastern side of the Kenyan Rift. A new Adolfus species is described from the Mathews Range in central Kenya.
The widely distributed Common Gartersnake (Thamnophis sirtalis) thrives in a variety of environments and preys upon a diversity of species. Phenotypic plasticity (including learning), as well as genetic diversity, may underlie the success of this species. We examined how different types of feeding experience influence the ontogeny of foraging behavior in garter snakes from two populations with different adult diets (earthworm or amphibian/worm/mammal diets) living on Beaver Island in Lake Michigan. Times to approach, capture, handle, and swallow prey were recorded in controlled laboratory settings. In Experiment I, neonatal snakes reared on fish, earthworms, or a mixed diet were tested for feeding skills at their first feeding, and at 5 subsequent intervals after feeding experience and diet-switching over a period of nearly 8 months. Snakes in all three groups decreased their latencies to consume prey after feeding experience and there were some litter, but no site or sex, differences. Snakes fed initially on worms were slow at consuming fish upon diet switching, whereas snakes that initially fed on fish rapidly consumed worms upon their first feeding. Feeding skills for initial prey were retained following the diet-switching phase. Experiment II determined the effects of long-term feeding experience on the abilities of field-caught adult snakes to detect, capture, and consume frogs, fish, and worms. Most foraging measures differed for all three prey, but there were few site differences and no sex differences. The effects of prior feeding experience appear to be less evident for adults than for neonates, which may be due to the effects of changing predator-prey body size relationships, changes in prey availability, or to constraints of the captive testing environment. Although populations on the island eat different prey, there is little evidence for genetic differentiation in foraging behavior during the several thousand years that the island has existed.
In animals with asymptotic growth after maturity, a variety of factors can lead to inter- and intraspecific variation in sexual size dimorphism (SSD). Growth-based models tailored for a particular taxon provide a useful framework for analyzing questions about the proximate bases, adaptive significance, and evolution of SSD. This paper shows how growth-based models designed for Anolis lizards have been used to study the effects of male territorial and competitive behavior on SSD and adult size distributions. In a comparative study of different species of anoles, indices of SSD based on male and female asymptotic snout-vent length (SVL) have been used to confirm a prediction from territorial theory that SSD should be related to inter-female distance. Within populations of Anolis sagrei and Anolis limifrons, adult size distributions were sometimes skewed in favor of larger males than predicted by null growth-based models, as a result of the underrepresentation of small, young males in samples containing females of the same age. A relative shortage of newly mature males in adult size distributions is consistent with behavioral studies suggesting that young, small males may bear the brunt of aggression from larger territorial males. Hence, growth-based models can be used to suggest and test behavioral and other hypotheses about the factors affecting SSD.
The Horn of Africa supports a unique and rich diversity of squamate reptiles. Among them, the gecko genus Hemidactylus stands out as the most species-rich genus of the region. In this study, we assembled a genetic and morphological data set of 22 Hemidactylus species that form a clade termed the African radiation, which is part of the arid clade of the genus. We reconstructed their phylogenetic relationships using both concatenation-based approaches and species tree inference. Hemidactylus laevis, H. ophiolepoides, and H. somalicus have been sequenced and placed in a phylogenetic context for the first time in this study. Our results confirm the phylogenetic placement of these species within the African radiation of the genus. Early diversification within the clade, however, remains obscure. According to the analysis of concatenated data, H. laevis is sister to the rest of the clade, whereas the species tree analyses inferred the African radiation to be formed by two subclades, northern and southern, and H. laevis belonging to the former. We integrate evidence from multiple sources including genetic differentiation at both mitochondrial and nuclear levels, morphological disparification, and coalescent-based species delimitation to support the existence of two new species of Hemidactylus. We provide a formal description of these two new species, one from northern Ethiopia, Eritrea, and westernmost Somaliland, and one from southern Ethiopia, northern Kenya, and easternmost South Sudan. Furthermore, we found that of the morphological traits examined, the numbers of supralabials and infralabials bear phylogenetic signal and we were able to tentatively infer the phylogenetic placement of species for which genetic data are still missing.
Ten species of Draco are recognized in the Philippines including one described as new. For each species, a diagnosis, description of squamation and color pattern, and summaries of distribution and natural history are provided. Keys to the Draco of the Philippines are also provided. The geographic distributions of Philippine Draco species are largely concordant with aggregate island complexes formed when sea levels were lower in the late Pleistocene. The biogeography of Palawan Island is considered in the context of Draco and found to be inconsistent with the standard model treating Palawan as an extension of the Greater Sunda Shelf.
The development of non-lethal techniques for sexing hatchling and immature desert tortoises is critical to population and ecological studies. Two methods for sexing desert tortoises were evaluated with respect to accuracy, efficiency, and suitability to field application. Laparoscopy was found to be 100% accurate and could be used on hatchlings as small as 28 grams total body mass. Plasma testosterone was 98% accurate for juvenile and immature tortoises ranging from 69-190 mm straight carapace length. Plasma testosterone is the most suitable methodology for field studies in that only a small blood sample is required for sexing purposes. Laparoscopy is 100% accurate; however, it may require holding the animal for an extended period of time.
We examined evaporative water loss of neonate (<1 yr old) tortoises in laboratory experiments designed to evaluate the dependence of evaporation on humidity, and of juvenile (1-4 yr old) tortoises in field experiments designed to reveal the influence of burrow microclimate on water gain and loss. In controlled laboratory conditions, rates of body mass loss which reflect net evaporative water losses, were independent of the difference in vapor density between the animal and its environment. Changes in skin permeability and respiratory parameters may account for this. Sleeping tortoises lost body mass half as fast as did active tortoises and hibernating individuals lost body mass 1/20th as quickly as active animals. Juveniles confined to short (20 cm) or long (70 cm) burrows in the field lost body mass faster in the drier and warmer short burrows. Doubly labeled water was used in tortoises residing in different burrow types to measure total (unidirectional) rates of evaporation, vapor influx and metabolic water production, to partition net water loss (as reflected in body mass loss) into its parts. Total evaporation rate was independent of burrow conditions, but tortoises in the longer, more humid burrows had higher rates of water vapor input and total water input than did those in shorter burrows. Thus, tortoises in long burrows lost body mass more slowly in response to a higher humidity, in contrast to neonates under laboratory conditions. Rates of body mass loss due to evaporation from neonates were relatively high in the laboratory (0.4 to 0.8% of body mass per day) and the field (0.7 to 1.1%/d) compared to those of adults in the laboratory (0.17%/d) or the field (0.1%/d). Thus, young tortoises apparently are obliged to rely on behavioral means (drinking pooled rain, withdrawing into their shell, seeking long, deep burrows) to avoid lethal dehydration in relatively hot, dry seasons.
Mating was observed in the fall (following nesting) and the spring (prior to nesting). Vitellogensis occurred during the fall prior to hibernation. Nesting was observed from May-early July with females producing one or two clutches. Clutches ranged from 2-7 eggs. Both males and females displayed seasonal testosterone cycles. -from Authors
Near times of gestation, oviposition, and parturition, habitat features that facilitate these processes may be specialized and of paramount importance to the fitness of gravid individuals. Additionally, spatial proximity to conspecifics may enhance individual fitness through antipredator, thermoregulatory, or osmoregulatory effects. Furthermore, philopatry and the proximity of littermates, parents, and offspring at the time of parturition of hatching would enhance inclusive fitness effects of mutualistic interactions. Mutual attraction to preferred habitat features as exhibited by gravid squamates may provide a useful model of early stages in the evolution of more complex social systems. Literature concerning aggregation of gravid squamates, communal nesting and birth, and interactions among neonates and postparturient females is reviewed. -from Authors
We review the taxonomic status of Philippine bent-toed geckos previously referred to Cyrtodactylus agusanensis. We delineate four evolutionary lineages within the C. agusanensis complex from the southeastern islands of the archipelago and describe three of these lineages as new species. The new species and true C. agusanensis are identified by numerous, nonoverlapping morphological characters and by allopatric ranges on separate islands. Our morphology-based taxonomic conclusions are bolstered by biogeographic evidence and marked interspecific divergence between monophyletic groups defined by mitochondrial and nuclear DNA sequences. To compliment these descriptions and enable future taxonomic work on Philippine Cyrtodactylus, we rediagnose and redescribe C. agusanensis. Because the holotype of C. agusanensis was destroyed in World War II, we designate a neotype for this species and restrict its geographic range to north central Mindanao Island. Our phylogenetic estimate suggests that the C. agusanensis complex originated in Mindanao and spread progressively north, diversifying incrementally with colonization of successive islands in a south-to-north pattern of biogeographic expansion and allopatric speciation.
On the basis of new material from Colombia, we describe external morphology, the hemipenis, osteology, musculature, and visceral morphology of Tropidodipsas perijanensis, a species previously known from the unique hologype and long assigned to Dipsas. Tropidodipsas perijanensis may be the sister species of all other Dipsadini or the sister species of a clade formed by Dipsas and Sibynomorphus. This distinctive South American species cannot be assigned to Tropidodipsas or to any other genus, and we erect a new genus for it. Our study of cephalic musculature identified a previously unreported division of the m. levator anguli oris and new insertion of the m. intermandibularis posterior superficialis. New characteristics of dispadine hemipenes were visualized by Alizarin staining. Some osteological characters of Dispadini support synonymization of Sibon and most species of Tropidodipsas, whereas visceral characters and published molecular data suggest that Dispas, Sibon, and Sibynomorphus form a clade.
The American Alligator (Alligator mississippiensis) is a crocodilian species that was once listed as endangered in the United States, but is now harvested both recreationally and commercially throughout its range in the southeastern United States. Harvest of alligators typically includes egg collecting and hunting. However, review of scientific literature reveals that the effects of harvest on alligator populations have received little scientific scrutiny. We built a theoretical simulation model to evaluate the impact of several harvest strategies on long-term (i.e., 100 years) alligator population trends. We used system dynamics software to develop the model and acquired data for the model from literature and field studies on alligator ecology. Although widely applicable across the species’ range and for other crocodilians, we used the Texas alligator management program as an example for model use. Results of model simulations showed that current harvest (50% egg harvest, 2% subadult harvest, 2% adult harvest) is sustainable, but alligator populations will stabilize at levels below population potential. The best harvest scenario for a sustainable harvest that maintains alligator populations at a relatively unchanging level is a 38% egg harvest, 2% subadult harvest, and 2% adult harvest. An elevated egg harvest (80%) can be sustained if no hunting harvest occurs. Contrarily, an increased hunting harvest (4% subadult, 4% adult) can be sustained with no egg harvest. This model identifies the function of current alligator harvest within populations and provides a tool for future use in determining the effect of changes in harvest or life-history characteristics on alligator population dynamics.
We studied scutellation and morphometrics in the gymnophthalmid lizards of the genus Alopoglossus. Six species are recognized: Alopoglossus angulatus, A. atriventris, A. buckleyi, A. copii, A. festae, and A. lehmanni. We place the nominal species Alopoglossus andeanus Ruibal in the synonymy of A. angulatus. We provide detailed descriptions and head scalation illustrations of each species, an identification key, and a distribution map. Se estudia la folidosis y morfometría de las lagartijas gymnophthalmidas del género Alopoglossus. Se reconocen un total de seis especies: Alopoglossus angulatus, A. atriventris, A. buckleyi, A. copii, A. festae y A. lehmanni. La especie nominal Alopoglossus andeanus Ruibal es considerada como sinónimo de A. angulatus. Se provee ilustraciones de la escamación de las cabezas, claves de identificación y un mapa de distribución.
Understanding community assembly is a fundamental goal of ecology and evolutionary biology, because it provides insight into how a given landscape changes in a synergistic fashion. With the current background of global environmental change, studies of how habitat alteration affects local communities often focus on species' responses to community-level changes instead of responses to specific ecological factors that elucidate the roles each factor plays in the final synergistic response. Here, we focus on the specific ecological mechanisms that drive changes in community structure. We investigated compositional patterns of lizard communities among natural and altered habitats (vegetatively sparse, natural, and dense) in the desert steppe ecosystem of Inner Mongolia, China. Habitat alteration induced significant changes in community composition of lizards and was associated with significant changes in both biotic and abiotic niches. Our preference (soil, thermal, and prey) and performance (locomotor, antipredator, and competitive) experiments identified many of the biotic and abiotic factors shaping lizard community responses to habitat change. In the natural habitat, where Phrynocephalus frontalis and Eremias multiocellata codominate, P. frontalis experienced low overlap (across lizard species) in preferred prey. Eremias multiocellata preferred the thermal environment of the natural habitat (and dense habitat), but this one factor did not fully explain its codominance. Phrynocephalus frontalis dominated in the sparse habitat, where this lizard species experienced its preferred tight soil and warm thermal environment and experienced low overlap of preferred prey. In the dense habitat, where E. argus dominates, P. frontalis and E. multiocellata exhibited impeded locomotor performance, whereas E. argus was not impeded by vegetation density. Eremias argus also preferred the thermal environment of the dense habitat (and natural habitat). Our results suggest, furthermore, that adult predation risk was not a major determinant of community divergence among habitats and that competition likely plays a more important role. Interspecific competition for microhabitat use may explain the low abundance of E. argus in the natural habitat and the low abundance of P. frontalis in the dense habitat. Overall, our assessment of lizard preferences and performances explained community composition across habitats. Our focus on ecological mechanisms associated with habitat alteration highlights the importance of vegetation conservation in lizard community management.
We redescribe Atractus punctiventris based on the examination of its holotype, two topotypes, and two additional specimens recently collected. We describe two new species of Atractus with 15 dorsal scale rows, previously confused with Atractus insipidus, from the eastern and western portions of Brazilian Amazonia, respectively. The new species are recognized on the basis of unique combinations of morphological characters. We compare Atractus punctiventris and the two new species with all congeners from most lowland provinces of cis-Andean South America. We discuss potential affinities of the three species, mainly by sharing exclusive hemipenial traits with congeners placed in different phenetic groups, and allocate them to distinct species groups of Atractus.
Multivariate analyses of variation in 30 scale characters for specimens of Lepidophyma from 63 Central American localities identify five morphological groups. Univariate comparisons of the groups diagnose four morphospecies. Two of these, L. smithii and L. mayae, appear to be bisexual. The all-female populations on the Pacific versant of Costa Rica are morphologically distinct and comprise L. reticulatum, which is sympatric with members of the L. flavimaculatum complex near Tilaran, Guanacaste Province. The all-female populations found in Panama and most of Caribbean Costa Rica are not distinguishable from northern populations that contain males, and these are retained together in the L. flavimaculatum complex. Within this complex, the available data on morphology, karyotypes, and allozymes suggest that the all-female populations may be of non-hybrid ("spontaneous") origin.
Our study represents the first attempt to describe biogeographic provinces for North American (México, United States, and Canada) turtles. We analyzed three nested data sets separately: (1) all turtles, (2) freshwater turtles, and (3) aquatic turtles. We georeferenced North American turtle distributions, then we created presence-absence matrices for each of the three data sets. We used watershed unit as biogeographic units. We conducted an unweighted pair-group method with arithmetic mean clustering analysis on each Jaccard index distance matrix from our watershed species matrices to delineate biogeographic provinces. Provinces were then tested for significant differences in species compositions in a global model with the use of a one-way analysis of similarity. We conducted a best subset of environmental variables with maximum (rank) correlation with community dissimilarities that determined the best model of abiotic variables explaining province delineation (i.e., climate, topography, and stream channel). To identify which species contributed the most to province delineations, we conducted an indicator species analysis and a similarity-percentage analysis. There were 16 all-turtle provinces, 15 freshwater provinces, and 13 aquatic provinces. Species compositions delineating the provinces were explained by abiotic variables, including mean annual precipitation, mean precipitation seasonality, and diversity of streams. Province delineations correspond closely with geographical boundaries, many of which have Pleistocene origins. For example, rivers with a history of carrying glacial runoff (e.g., Arkansas, Mississippi) sometimes dissect upland provinces, especially for aquatic and semiaquatic turtles. Compared with freshwater fishes, turtles show greater sensitivity to decreased temperature with restriction of most taxa south of the last permafrost maximum. Turtles also exhibit higher sensitivity to climatic, geomorphic, and tectonic instability, with richness and endemism concentrated along the more stable Gulf of México and Atlantic (south of the last permafrost maximum) coasts. Although distribution data indicate two aquatic turtles are most cold tolerant (i.e., Chrysemys picta, Chelydra serpentina), aquatic turtles overall show the most restriction to warmer, wetter climates. Sequential addition of semiaquatic and terrestrial turtles into analyses shows, as expected, that these taxa flesh out turtle faunas in climatically harsh (e.g., grasslands) or remote (e.g., California, Sonoran Desert) regions. The turtle assemblages of southwestern versus southeastern North America are distinct. But there is a transition zone across the semiarid plains of the Texas Gulf Coast, High Plains, and Chihuahuan Desert, including a strong boundary congruent with the Cochise Filter-Barrier. This is not a simple subdivision of Neotropical versus Nearctic taxa, as some lineages from both realms span the transition zone.
We analyze the various populations of frogs of the Eleutherodactylus rugulosus group. This group ranges from Mexico to Panama and most species occur in riparian habitats, although in diverse kinds of forests at elevations ranging from sea level to above 2000 m. In most regions of Middle America, one to several species of these frogs comprise a conspicuous component of the herpetofauna. We recognize 33 species in the E. rugulosus group; in this paper 10 new species are described and six names are removed from synonymy and considered to represent valid species. For each species, we trace the taxonomic history in synonymy, provide a diagnosis and definition, address variation, and summarize the distribution, habits, and habitat. Particularly problematical, E. rugulosus previously was thought to range from Mexico to Panama. As we conceive it, this species is restricted to the Pacific versant of Mexico. We allocate other, more southern populations of frogs previously ascribed to this species to species other than E. rugulosus.
The Leptodactylus latrans species group currently comprises eight medium- to large-sized frog species with a convoluted taxonomic history, particularly related to the specific limits of the L. latrans complex, and the species pair Leptodactylus chaquensis– Leptodactylus macrosternum. Their homogeneous external morphology and continental geographic distribution in South America have posed severe limitations to a comprehensive review, such that taxonomic consensus and species limits remain uncertain. This is further worsened by the presence of chromatic polymorphism among coexisting species that can hardly be distinguished by external morphology. Based on a large-scale geographic sampling including multilocus DNA analyses, and acoustic and morphological data, we provide a comprehensive evaluation of the taxonomic status and species limits of the L. latrans group, focusing on the resolution of the L. latrans complex and the species pair L. chaquensis– L. macrosternum. We gathered 728 mitochondrial sequences from 429 localities, encompassing the entire geographic distribution of the group. Both generalized mixed Yule coalescent and automatic barcode gap discovery species delimitation methods recovered four major mitochondrial evolutionary lineages within the L. latrans complex, also supported by distribution patterns, multilocus molecular, morphological and/or bioacoustic data. One lineage is linked to nominal L. latrans, one revalidated as Leptodactylus luctator, and the other two are formally named and described. Another lineage encompasses all specimens previously assigned to the species pair L. chaquensis–L. macrosternum, clustered as a single evolutionary entity and is now regarded as L. macrosternum. We provide a revised diagnosis for these species based on acoustic data, morphological/chromatic variation, and phylogenetic relationships of all species currently included in the L. latrans group. Our findings reinforce the view that Neotropical diversity is highly underestimated and stress that appropriate geographic sampling in an integrative framework is crucial for the establishment of specific limits among broadly distributed and morphologically cryptic Neotropical frogs.
The endemic amphibian fauna of the Seychelles Archipelago may have originated through a vicariance event in the early Cenozoic when the microcontinent that formed this group of islands rifted away from India. Albumin evolution in the three endemic genera of caecilians (Caeciliaidae: Grandisonia, Hypogeophis, and Praslinia) was examined using the quantitative immunological technique of micro-complement fixation (MC'F). The data obtained and additional DNA sequence data from mitochondrial genes provide further evidence for the monophyly of this group and suggest a time frame for divergences within the group. Praslinia apparently diverged first, approximately 30 million years before the present (mybp), while the separation of Hypogeophis and Grandisonia, as well as speciation within Grandisonia, has occurred within the last 14 million years. Albumins of Seychellean caecilians average 106 units of immunological distance (ID) to the other members of the Caeciliaidae that were examined. Based upon the standard calibration of the albumin clock, this is consistent with the timing of the rifting of the Seychelles from India and suggests that this vicariance event may have been responsible for the isolation of these taxa. Three other members of the Caeciliaidae and one member of the Typhlonectidae were available for this study. Dermophis and Schistometopum cluster (mean ID = 59), and form the sister taxon of the Seychellean genera, while Caecilia and Typhlonectes cluster at a mean ID of 78. Albumin from representatives of two other families examined (Ichthyophiidae and Rhinatrematidae) were so different that measurements were outside the quantitative limits of MC'F; these taxa appear to be distantly related to the Caeciliaidae and Typhlonectidae, as well as to each other.
Plethodontid salamanders of the genus Batrachoseps comprise a clade of morphologically similar, elongate species whose great genetic diversity is being revealed through molecular studies. We used allozymes and mtDNA sequences to study variation in 62 populations from central coastal California, treated most recently as members of the B. pacificus complex. Analyses of mtDNA data identify four lineages that are well differentiated from each other and do not form a monophyletic group. Instead, the central coastal lineages are multiply paraphyletic with respect to the southern California members of the pacificus group. Marked allozymic differences show that these four lineages are strongly differentiated, although some limited gene exchange may have occurred in the past. Each lineage is also morphologically distinctive, but the differences between them are subtle. Because these lineages appear to be evolving independently, we describe them as new species: B. luciae, B. incognitus and B. minor, distributed parapatrically from north to south in the Santa Lucia Mountains of coastal Monterey and San Luis Obispo Counties, and B. gavilanensis, occurring mainly inland from the range of B. luciae, centered on the Gabilan Mountains, but also extending to the Pacific coast at the north end of the range of the complex, along the northern border of Monterey Bay. Although no sympatry is known among any of the new species, B. luciae and B. gavilanensis are narrowly parapatric. Furthermore, all but B. luciae occur in sympatry with other members of the genus in at least a part of their geographic ranges. The new species may have arisen vicariantly with respect both to each other and to related forms in southern California, in part as a result of the dramatic tectonic movements that have characterized the last 15 million years of geological history in western North America.
We investigated patterns of variation at 22 allozyme loci in 53 populations of salamanders currently referred to Desmognathus ochrophaeus Cope. Analyses of genetic distance data revealed that a homogeneous and well-diffentiated form is distributed from New York to southeastern Kentucky, in and northwest of the Ridge and Valley Physiographic Province. To the south, two relatively well-differentiated, genetically homogeneous forms replace each other para-patrically in the Blue Ridge Physiographic Province at Iron Mountain Gap on the Tennessee-North Carolina border and somewhere between Linville Falls and McKinney Gap on the Blue Ridge divide. Farther south, a loose collection of relatively well-differentiated populations occupies the Blue Ridge Physiographic Province south of the Pigeon River. Patterns of isolation by distance are evident for interpopulational comparisons both within and among these forms, and genetic differentiation has been accompanied by various degrees of ethological reproductive isolation. We propose that the application of a single name to this complex of populations is no longer tenable, and name the four forms (from northeast to southwest): ochrophaeus, orestes sp. nov., carolinensis, and ocoee.
The phylogeny of the Gymnophiona is poorly understood and until recently received little attention. Within the past three years, four separate classifications of caecilians were published. Two of these classifications, those of Wake (1985, 1986) and Duellman and Trueb (1986), are conservative and do not differ substantially from the classification of Taylor (1968, 1969a) as modified by Nussbaum (1977, 1979). However, the classifications of Laurent (1986) and Lescure et al. (1986) differ radically from the others and from each other. Laurent's classification is biased by a priori biogeographical considerations and is otherwise difficult to evaluate, because he did not clarify his methodology or justify his dendrogram by explaining his characters and their transformations. Lescure et al. claimed that their analysis of caecilian phylogeny and their classification are based on strict cladistic principles; however, like Laurent, they did not explain their procedures and used distributional data in deriving their phylogeny. There is no logical basis for using non-inherited characters such as geographic distribution to estimate phylogenies, and we disagree with this practice. Lescure et al. relied heavily on their scheme of annular development in determining their cladogram. We demonstrate that their interpretation of the ontogeny and phylogeny of caecilian annuli is wrong. We reject the cladogram of Lescure et al., because (1) many of the characters upon which it is based are poorly defined and incorrectly coded (83% of the transformations are either changes in annulation or geographic distribution) and (2) it is not supported by rigorous cladistic analyses of their own data. The classification of Lescure et al. is based on their seriously flawed cladogram and incorporates dubious classification procedures. Present knowledge does not allow establishment of a robust, phylogenetic classification of caecilians. We present an interim classification of caecilians with diagnoses to the generic level, recognizing six families (Rhinatrematidae, Ichthyophiidae, Uraeotyphlidae, Scolecomorphidae, Caeciliaidae, Typhlonectidae) and 34 genera. The first four families are likely to survive cladistic analysis, but the Caeciliaidae is a paraphyletic subgroup of a monophyletic clade that includes the caeciliaid and typhlonectid genera. Various attempts to subdivide the Caeciliaidae are either clearly wrong or unconvincing and, in all cases, are based on inadequate data and procedures. We recognize no categories of Gymnophiona other than family, genus, and species.
Desmognathus santeetlah and D. fuscus hybridize extensively along the north- western escarpment of the Great Smoky Mountains. Patterns of clinal variation in electromorph frequencies differ between two loci and between different areas along the Great Smokies escarpment. Electromorphic variation is not always concordant with variation in color pattern. Gene exchange seems to diminish toward the southwest. These patterns may reflect historical variation in levels of gene flow. The two species are electrophoretically more similar than most plethodontid species and gene exchange between them may be restricted solely by geographic isolation. Nevertheless, D. santeetlah is a relatively distinctive, homogeneous form. Retention of its current taxonomic status is recom- mended until reproductive isolation between it and D. fuscus has been more thoroughly studied.
Amphibia and its major groups are defined according to principles of phylogenetic taxonomy, and the implications of the definitions for amphibian systematics are discussed. The results of phylogenetic analyses of Amphibia, Anura, Caudata, and Gymnophiona from morphological and molecular studies are compared, based on papers published in the symposium "Amphibian relationships: Phylogenetic analysis of morphology and molecules" at the 1990 meetings of the American Society of Zoologists in San Antonio, Texas. Several issues related to the use of morphological and molecular data sets are discussed briefly: quality and quantity of data, homology assessment, nonindependence of characters, sampling of taxa, and resolution of trees derived from different data sets.
In the past decades, herpetologists have studied intensively the amphibians of Bolivia, increasing dramatically the number of species known for the country. There are currently 266 species recorded, but this number will increase with the addition of many new country records and the description of species new to science, especially within Andean Craugastoridae. Deforestation, habitat destruction (mostly due to agriculture), water pollution, and chytridiomycosis are the main causes of amphibian declines in Bolivia. Andean frogs are much more affected than lowland species. Infection by the chytrid fungus Batrachochytrium dendrobatidis is widespread. Forest species of the Andean genus Telmatobius have disappeared from known sites and some other Andean taxa have declined severely. Here, we revise the International Union for Conservation of Nature conservation status categories for some species of anurans. Public awareness is increasing thanks to different local initiatives addressing projects to protect Bolivian amphibians.
The Rhinella spinulosa group is a clade of toads that inhabit the Andes mountains from northern Ecuador to Patagonia. Its taxonomy was recently revised, and in its new arrangement comprises nine species, including Rhinella gallardoi, traditionally placed in a different intrageneric group. In this work we studied the larval external and internal morphology in this group, by describing for the first time tadpoles of R. achalensis, R. gallardoi, and R. vellardi, and then summarizing morphological data for R. altiperuviana, R. limensis, R. papillosa, R. spinulosa, and R. trifolium. Although we found no diagnostic larval features for the whole clade, two distinct morphs were identified. Most tadpoles were highly pigmented and slender, and their oral discs showed a long gap in the second labial tooth row; conversely, tadpoles of R. limensis and R. vellardi shared a globose body and a very short gap. Buccal and musculoskeletal features were highly conserved within the group and regarding other Rhinella, and included four lingual papillae, nonkeratinized spurs, tripartite suprarostral cartilages, quadrato-orbital commissure, and in musculature, m. subarcualis rectus II–IV invading the branchial septum III and laryngeal muscles reduced or absent.
Gerrhonotus liocephalus is demonstrated to consist of at least three species rather than the single polytypic species currently recognized. Of the seven currently recognized subspecies, G. l. aguayoi, G. l. infernalis and G. l. taylori become G. infernalis; G. l. ophiurus and G. l. loweryi become G. ophiurus; and G. l. austrinus and G. l. liocephalus retain the name G. liocephalus. No subspecies are recognized within any of these three species. Certain populations from western Mexico (Durango, Sinaloa, Jalisco, and Colima) remain of uncertain identity, but are tentatively referred to as G. cf. liocephalus. Evidence for these conclusions is derived from an analysis of scalation, coloration, and morphometric variation. The taxonomic history in Gerrhonotus also is discussed.
Anoles have evolved independently on each island in the Greater Antilles, producing a suite of morphologically-distinct species that utilize different microhabitats. Comparisons among islands indicate that the same set of "ecomorphs" - distantly related species that are similar in morphology, ecology, and behavior - has evolved on each island. Despite considerable work on anoles over the past three decades, much remains to be learned about evolution of the ecomorphs. In particular, previous studies have focused on external measurements of gross limb proportions, tail length, mass, and number of lamellae. Using a variety of techniques, we examined these characters in greater detail and investigated a wide variety of other characters. We found that the ecomorph classes represent distinct entities in morphological space when morphological characters are examined in greater detail (e.g., each limb element was treated separately). In addition, we found that the ecomorphs differ in a variety of characters not previously examined, including toe pad area, pectoral and pelvic girdle dimensions, head dimensions, and tail shape. These differences were apparent regardless of how we defined body size, although comparisons of particular characters were affected by which body size variable was used. This finding indicates that convergence in ecomorph evolution extends beyond traits directly linked to habitat use and locomotion. We also examined a number of other taxa that have not traditionally been considered to be members of any ecomorph class. We found that many descendants of ecomorphs living on small islands near the Greater Antilles no longer belong to the ecomorph class of their ancestor. Many Lesser Antillean anoles appear to be trunk-crown anoles, whereas others do not belong to any ecomorph class. Montane anoles of the Greater Antilles and Chamaelinorops also do not belong to any ecomorph class, but Chamaeleolis, and possibly Phenacosaurus, are twig anoles.
To test the hypothesis that males will more vigorously defend high-value territories (those containing females versus those with no females), male green anoles (Anolis carolinensis) were allowed to establish residency in 50 × 25 × 31-cm terraria with or without a female present. Each male was then removed for 1, 3, 5, or 7 h while an intruder was given access to the terrarium. The original owner was then returned to the terrarium with the intruder present, and the aggressive acts of both males were recorded. An aggression index was calculated for each owner-intruder pair to determine which member "won" the contest. Owners won more contests than intruders after all removal times except 7 h. Aggression did not increase significantly at intermediate removal times, when both males may have perceived themselves as territory owners. When the value of a territory was increased by the presence of a female, aggression by both the owner and the intruder increased significantly after the 3-h owner removal time, and aggression by the intruder (but not owner) increased significantly after the 5-h owner removal time. Winners of territorial contests in male green anoles seem to be determined by the resource holding potential of the contestants, the value of a contested territory, and particularly the ability of males to assess each other.
Skull characters were examined and combined with posteranial osteological, external, allozyme, DNA sequence, and chromosome data from the literature to estimate the phylogenetic relationships of the Hispaniolan dwarf twig Anolis (A. sheplani, A. insolitus, and A. placidus). A survey of most species of Anolis species for which skeletons are available found two osteological character states unique to these species, a convex parietal roof and crenulated parietal edges, thus suggesting that the Hispaniolan twig dwarfs form a monophyletic group. To assess this hypothesis of monophyly and to estimate the phyletic placement of these species in the genus Anolis, parsimony analyses were undertaken including all proposed close relatives of the Hispaniolan twig dwarfs and a taxonomically and geographically diverse sample of congeners. Diagnostic synapomorphies found in this analysis were surveyed more widely in Anolis. Characterization difficulties of the skull data were addressed by using three coding methods to differentially code intraspecific and continuous variation. Confidence in the Hispaniolan twig dwarf relationships was assessed with the bootstrap, the test of Templeton, and the agreement between results from the three coding methods. The monophyly of the Hispaniolan twig dwarfs was strongly supported. The nearest relatives of the Hispaniolan twig dwarfs appear to be twig species from Hispaniola (A. darlingtoni), Puerto Rico (A. occultus), and South America (tigrinus group, i.e., A. solitarius), and Phenacosaurus. Wider taxonomic and character sampling is needed to assess the robustness of these clades, but present evidence suggests an invasion of Hispaniola or Puerto Rico from South America and, counter to the usual opinions of ecomorph occurrence by intra-island adaptive radiation, a clade of twig species on three different land masses.