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Populations of the green turtle (Chelonia mydas), a mega-herbivore that consumes seagrasses, are recovering worldwide. Understanding green turtle adaptations to herbivory and responses to changes in seagrass availability will be critical to interpreting plant–herbivore interactions as green turtle populations continue to rebound. Ingesta particle size and diet composition of two green turtle foraging aggregations (Bermuda, 32.3° N, 64.8° W; U.S. Virgin Islands [USVI], 17.8° N, 64.6° W) in the Northwest Atlantic (NWA) were evaluated to assess the prevalence of herbivory across foraging sites and life stages, determine if there is an optimum ingesta particle size, and evaluate green turtle responses to changes in seagrass availability. Both aggregations were herbivorous (> 90% seagrass/algae) across size classes (straight carapace length, SCL). Ingesta particle size (mean ± SD) did not differ between Bermuda (2.6 ± 1.4 cm) and the USVI (2.3 ± 1.2 cm). Of seagrass leaves ingested, 20–30% were 1.7 cm in length, indicating a potential optimum for maximizing digestion rates. Turtle size (SCL) had a significant effect on particle size in Bermuda (p = 0.01, R2 = 0.16) (35.1 ± 9.9 cm SCL) but not in the USVI aggregation, which was comprised of larger turtles (49.0 ± 6.1 cm SCL). In Bermuda, there was no apparent response to the declines in seagrass availability. Ingesta particle size and volume of seagrass leaves did not decline from 2015 to 2019, nor was there an increase in volume of seagrass roots and rhizomes. These results indicate herbivory is prevalent across size classes at two NWA foraging sites and ingesta particle size has important implications for optimizing the green turtle grazing strategy and facilitating ontogenetic diet shifts to herbivory in juveniles. Ingesta particle size is a valuable tool for assessing green turtle responses to seagrass declines that should be interpreted within the context of population demographics.

The conservation and management of endangered species, including sea turtles, require consistent long-term monitoring of productivity (e.g., number of hatchlings emerged per nest, per female, per nesting site, per population). In sea turtle species, some of the relevant data are obtained by estimating the number of hatched eggs from fragments found in the nest after hatching. Yet, no formal assessment of the associated error has been published. Here we provide an estimation of the error associated with the most widespread method used to determine sea turtle productivity (count of shell fragments > 50% of the egg size) using a large dataset (n = 8539) of actual and estimated clutch sizes of four sea turtle species (Caretta caretta, Chelonia mydas, Dermochelys coriacea, Eretmochelys imbricata). The data are analyzed through linear mixed models with several explanatory variables. Results show that the error can be large in certain cases and, when the associated error rate is not adequately considered, may represent a serious problem in studies on reproductive parameters such as clutch size. Some significant explanatory variables suggest that some sources of error are linked to species-specific biological traits (e.g., clutch size, egg size, nest depth), and others imply human error. Other biotic and abiotic factors may also be involved. We recommend that—whenever possible—errors be assessed and adequately reported by studies that estimate clutch size, hatching and emergence success, or hatchling production.

Longevity patterns in most vertebrates suggest that females benefit most from maintenance investment. A reversed longevity pattern in loggerhead musk turtles (Sternotherus minor) allowed us to test trade-offs between maintenance and survivorship. We tested the hypothesis that the sex with greater longevity has greater maintenance than the sex with shorter longevity. We also compared the following parameters between sexes: Bactericidal ability (BA) and heterophil:lymphocyte ratios (HLR). Baseline blood samples were collected from turtles in the field; a subset of turtles was returned to a laboratory for experiments of acquired immune responses to sheep red blood cells (SRBC). We found no support for the original hypothesis of reversal in sex-dependent immune trade-offs (difference between sex SRBC titers: p = .102; interaction between treatment and sex: p = .177; difference between treatments: p

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.

Marine turtles are challenging species to protect because they occur over large geographic scales. Tagging individual turtles at nesting beaches and foraging areas, and the resulting mark-recapture data sets have gradually enabled us to understand marine turtle migratory behaviour and dispersal. Within the Caribbean region, several turtle tagging projects have led to longer-term evaluations and assessments of connectivity. Thus, marine turtle mark-recapture data is important for developing conservation strategies at regional-scale. In this study, we analyse turtle tagging data from the Gulf of Venezuela to determine regional (Caribbean and Atlantic geographic level) and local (within the Gulf of Venezuela) links. To achieve this, we retrieved, compiled, and analysed multiple databases with records of marine turtles that were tagged and then recaptured in the Gulf of Venezuela. Sixty-six tag return records were evaluated, 43 from animals initially tagged outside of the Gulf of Venezuela and then recaptured inside, plus 23 records retrieved from turtles that were tagged and recaptured within the Gulf of Venezuela. We found evidence of connectivity between 12 different locations where initial tagging events occurred, eight from other feeding areas and four from nesting beaches. We described four different movement patterns for 23 turtles tagged and re-captured within the Gulf of Venezuela. Most of the recapture records we obtained occurred after the turtles were known, or presumed, to have been killed by local fishers. Hence, knowing patterns of dispersal and connectivity are crucial to improving local and regional conservation and threat mitigation.

The understanding of developmental and reproductive migrations of sea turtles is essential for effective protection and conservation efforts. Flipper tags remain a valuable method for detecting movements and migrations because they are cost-effective and conspicuous, allowing the detection of a tagged animal by any person worldwide. Here we report 13 flipper-tag recoveries for Brazilian hawksbill (Eretmochelys imbricata) turtles that augment the body ofinformation on the migratory nature of this species and provide new growth-rate data.

The Bocas del Toro region of Panama (Bocas del Toro Province and the Comarca Ngobe-Bugle) has been known as an important area for sea turtles since at least the 17th century. Four species occur in the region: the hawksbill (Eretmochelys imbricata), green turtle (Chelonia mydas), loggerhead (Caretta caretta), and leatherback (Dermochelys coriacea). Multiple life stages of these species are supported by the diverse marine habitats and beaches in the region. We summarize the evidence for stages present and their known distributions in the Bocas region. Annual nest numbers, location, and monitoring status are given for 17 nesting beaches. These beaches support regionally significant numbers of leatherback and hawksbill nests, small numbers of green turtle nests and, rarely, loggerhead nests. We review the history of sea turtle use in the Bocas region and describe “velacion,” a government-organized system that facilitated the extraction of hawksbills from nesting beaches throughout the Bocas region du...

In response to a call from the US National Research Council for research programs to combine their data to improve sea turtle population assessments, we analyzed somatic growth data for Northwest Atlantic (NWA) loggerhead sea turtles (Caretta caretta) from 10 research programs. We assessed growth dynamics over wide ranges of geography (9–33°N latitude), time (1978–2012), and body size (35.4–103.3 cm carapace length). Generalized additive models revealed significant spatial and temporal variation in growth rates and a significant decline in growth rates with increasing body size. Growth was more rapid in waters south of the USA (

Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long‐lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio‐temporal effects on hawksbill growth dynamics over a 33‐yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio‐temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region‐wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0‐ or 1‐yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs.

We describe isolation and characterization of 14 polymorphic tetranucleotide loci from the hawksbill turtle (Eretmochelys imbricata). We identified an average of 14.5 alleles per locus based on screening of 36 individuals captured on foraging grounds in Bocas del Toro Province, Panama, and 9.6 alleles in 13 individuals captured on foraging grounds in Bermuda. Observed heterozygosity ranged from 0.67 to 1.00, with a mean of 0.85 for the Panama foraging aggregation and 0.83 for the Bermuda foraging aggregation. This microsatellite suite has a combined non-exclusion probability of identity of 8.26 × 10–23. These markers should be informative in individual and population-focused analyses.

The existence of ontogenetic shifts in habitat by marine turtles, and of immature-dominated assemblages in “developmental habitat,” were important concepts first proposed by Archie Carr in 1956. Results of long-term, in-water capture programs in Caribbean Panama (17 yr) and Bermuda (37 yr) allow the testing and refinement of these ideas, in particular the developmental habitat hypothesis for Chelonia mydas, Eretmochelys imbricata, and Caretta caretta. A literature survey reviews worldwide studies on these species, and also incorporates Lepidochelys kempii. The studies in Panama and Bermuda reported in this paper use netting, mark/recapture, laparoscopy, and satellite telemetry to investigate size distributions, maturity status, residency, site fidelity, and developmental migrations of three species of sea turtles at three study sites. Characteristics of benthic developmental habitat of C. mydas, E. imbricata, L. kempii, and, to a lesser extent, C. caretta in the Atlantic Ocean usually include ben...

The family Podocnemididae consists of 20 genera and 30 species considered here as valid and diagnosable by cranial characters. Three of these genera and eight species persist into the Recent fauna, barely reflecting the evolutionary diversity and distribution of the group. The family extends from the Late Cretaceous to the Recent and occurs in North and South America, Europe, Asia, and Africa. A phylogenetic analysis utilizes 31 podocnemidid taxa (30 named and one unnamed; a total of 37 taxa analyzed includes outgroups) in the Podocnemididae that are analyzed using PAUP. The resulting consensus of nine equally parsimonious cladograms is the basis for a new classification of the family. The family Podocnemididae is reconfirmed as monophyletic, using the unique possession of a cavum pterygoidei formed by the basisphenoid, pterygoid, prootic, and quadrate, underlain by the pterygoid and basisphenoid, among other characters. Much of our resolution agrees with that of Franca and Langer (2006), which c...

Despite intense interest in conservation of marine turtles, spatial ecology during the oceanic juvenile phase remains relatively unknown. Here, we used mixed stock analysis and examination of oceanic drift to elucidate movements of hawksbill turtles (Eretmochelys imbricata) and address management implications within the Caribbean. Among samples collected from 92 neritic juvenile hawksbills in the Cayman Islands we detected 11 mtDNA control region haplotypes. To estimate contributions to the aggregation, we performed 'many-to-many' mixed stock analysis, incorporating published hawksbill genetic and population data. The Cayman Islands aggregation represents a diverse mixed stock: potentially contributing source rookeries spanned the Caribbean basin, delineating a scale of recruitment of 200-2500 km. As hawksbills undergo an extended phase of oceanic dispersal, ocean currents may drive patterns of genetic diversity observed on foraging aggregations. Therefore, using high-resolution Aviso ocean current data, we modelled movement of particles representing passively drifting oceanic juvenile hawksbills. Putative distribution patterns varied markedly by origin: particles from many rookeries were broadly distributed across the region, while others would appear to become entrained in local gyres. Overall, we detected a significant correlation between genetic profiles of foraging aggregations and patterns of particle distribution produced by a hatchling drift model (Mantel test, r = 0.77, P < 0.001; linear regression, r = 0.83, P < 0.001). Our results indicate that although there is a high degree of mixing across the Caribbean (a 'turtle soup'), current patterns play a substantial role in determining genetic structure of foraging aggregations (forming turtle groups). Thus, for marine turtles and other widely distributed marine species, integration of genetic and oceanographic data may enhance understanding of population connectivity and management requirements.

In Parham and Irmis’s (2008) commentary on our article “Assessing Concordance of Fossil Calibration Points in Molecular Clock Studies: An Example Using Turtles” (Near et al. 2005), these authors address three areas of concern with respect to fossil calibration analyses in general and our article in particular: (1) absolute age estimates for fossil calibration points, including the accuracy of the reporting of age information and the inclusion of stratigraphic error; (2) the use of fixed calibration points in clock calibration studies; and (3) the phylogenetic placement of fossil taxa in our article. Before we discuss the points raised by Parham and Irmis, it is important to emphasize that the primary goal of our article was to provide a new methodological approach for incorporating uncertainty and error into molecular clock calibration estimates. In that article, we developed a new method, based on cross-validation with multiple calibration points, to identify outlier fossils that may have been inaccurately dated or phylogenetically misplaced or that had otherwise been providing inaccurate dates for clade divergences. We applied that method to turtles because they have an excellent fossil record and have been

Chiriqui Beach, in the Comarca Ngobe-Bugle on the Caribbean coast of Panama, is the most important nesting beach for leatherback turtles (Dermochelys coriacea) in Caribbean Central America. Beach surveys during the 2003 and 2004 nesting seasons documented 3077 leatherback nests in one season and a minimum of 234 individual leatherbacks. Monitoring of nest fate revealed that predation by dogs represents the greatest human-related survival threat to leatherbacks at Chiriqui Beach, although the killing of leatherbacks from the same nesting population on beaches near the Panama–Costa Rica border also is of concern.

Determining sex ratios of endangered populations is important for wildlife management, particularly species subject to sex-specific threats or that exhibit temperature-dependent sex determination. Sea turtle sex is determined by incubation temperature and individuals lack external sex-based traits until sexual maturity. Previous research utilized serum/plasma testosterone radioimmunoassays (RIA) to determine sex in immature/juvenile sea turtles. However, there has been a growing application of enzyme-linked immunosorbent assay (ELISA) for wildlife endocrinology studies, but no study on sea turtles has compared the results of ELISA and RIA. This study provides the first sex ratio for a threatened East Pacific green sea turtle (Chelonia mydas) foraging aggregation, a critical step for future management of this species. Here, we validate a testosterone ELISA and compare results between RIA and ELISA of duplicate samples. The ELISA demonstrated excellent correspondence with the RIA for providing testosterone concentrations for sex determination. Neither assay proved reliable for predicting the sex of reproductively active females with increased testosterone production. We then applied ELISA to examine the sex ratio of 69 green turtles foraging in San Diego Bay, California. Of 45 immature turtles sampled, sex could not be determined for three turtles because testosterone concentrations fell between the ranges for either sex (females: 4.1-113.1 pg/mL, males: 198.4-2,613.0 pg/mL) and these turtles were not subsequently recaptured to enable sex determination; using a Bayesian model to predict probabilities of turtle sex we predicted all three 'unknowns' were female (> 0.86). Additionally, the model assigned all turtles with their correct sex (if determined at recapture) with 100% accuracy. Results indicated a female bias (2.83F:1M) among all turtles in the aggregation; when focusing only on putative immature turtles the sex ratio was 3.5F:1M. With appropriate validation, ELISA sexing could be applied to other sea turtle species, and serve as a crucial conservation tool.

Although pleurodires have been considered significantly less diverse than their sister group, the cryptodires, current discoveries show that pleurodires had a more complex and extensive evolutionary history than had been realized. Previously unknown radiations, particularly in the near-shore marine realm, are revealed by taxa with diverse cranial morphology, indicating many different feeding and sensory strategies. The pleurodire group that is changed the most by the new discoveries is its largest group, the hyperfamily Pelomedusoides. The hyperfamily Pelomedusoides now consists of the families Pelomedusidae, Podocnemididae, Bothremydidae, Araripemydidae, and Euraxemydidae, new family. The families Bothremydidae, Araripemydidae, and Euraxemydidae, new family, are documented with descriptions of skulls, lower jaws, and shells. The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily ...

Although still controversial, estimation of divergence times using molecular data has emerged as a powerful tool to examine the tempo and mode of evolutionary change. Two primary obstacles in improving the accuracy of molecular dating are heterogeneity in DNA substitution rates and accuracy of the fossil record as calibration points. Recent methodological advances have provided powerful methods that estimate relative divergence times in the face of heterogeneity of nucleotide substitution rates among lineages. However, relatively little attention has focused on the accuracy of fossil calibration points that allow one to translate relative divergence times into absolute time. We present a new cross-validation method that identifies inconsistent fossils when multiple fossil calibrations are available for a clade and apply our method to a molecular phylogeny of living turtles with fossil calibration times for 17 of the 22 internal nodes in the tree. Our cross-validation procedure identified seven inconsistent fossils. Using the consistent fossils as calibration points, we found that despite their overall antiquity as a lineage, the most species-rich clades of turtles diversified well within the Cenozoic. Many of the truly ancient lineages of turtles are currently represented by a few, often endangered species that deserve high priority as conservation targets.

We conducted a 13-year study of a stream community of eight turtle species in a west-central Florida spring-run. A major shift towards smaller species is apparent when this study is compared to another made at the same locality six decades earlier. Over the duration of our study, sizes of Pseudemys concinna and P. floridana populations appeared to increase, though not to the levels of six decades previously. Average adult size for both species also increased significantly; these changes may reflect enhanced levels of protection. Growth rates of P. concinna and P. floridana vary throughout life and appear to be strongly seasonal. In light of constant water temperature and abundant food, we suggest that basking behaviors may limit growth, and the availability of basking sites may be critical to the health of the population. Data on sexual dimorphism in P. concinna and P. floridana are also presented.

Hawksbill Seaturtles have temperature-dependent sex determination. As such, the resulting sex ratios are of conservational and ecological significance. Buck Island Reef is an interesting location for sex ratio studies since it represents a natural and unexploited foraging ground for hawksbills in the Caribbean. To examine sex ratios, blood samples were obtained from juvenile Hawksbill Seaturtles captured on Buck Island Reef over a four-year period. We used a radioimmunoassay to determine testosterone levels in those samples and compared those values to testosterone levels of juvenile hawksbills from the Caribbean whose sex has been verified by laparoscopy. The results of this study reveal a significantly female-biased sex ratio (approximately 80% female) occurs in this juvenile aggregation inhabiting Buck Island Reef.

The Cenomanian redbeds of southern Morocco have yielded skulls of a new genus and two new species of side-necked turtles, Galianemys whitei and Galianemys emringeri. The genus is based on a series of nine well-preserved skulls and three partial skulls. Galianemys is a pelomedusoid pleurodire belonging to the family Bothremydidae Baur, 1891, because it has: (1) precolumellar fossa absent, (2) foramen stapedio-temporale facing anteriorly, (3) eustachian tube separated from stapes by bone, and (4) exoccipital-quadrate contact. Within the Bothremydidae Galianemys is best resolved as the sister group to Cearachelys because both have the jugal retracted from the orbital margin and a small, slitlike fenestra postotica. Galianemys emringeri has a deep fossa pterygoidei, ventrally exposed prootic, foramen nervi facialis and foramen nervi vidiani, a thicker labial ridge, and the jugal not exposed on the triturating surface, while Galianemys whitei has a shallow fossa pterygoidei, covered prootic and forame...

The known material of the side-necked turtle Dacquemys paleomorpha Williams, 1954, consists of the type skull and a new skull from the late Eocene of Egypt. Dacquemys is reaffirmed as a member of the Podocnemididae because of its well-developed cavum pterygoideus. Within the Podocnemididae Dacquemys uniquely possesses a fully roofed temporal region produced by a posteriorly extensive parietal and wide supraoccipital, a very wide interorbital area, and two accessory maxillary ridges meeting anteriorly to form an enclosed trough.

Maximum likelihood mixed stock analysis was used to identify the natal origin of immature loggerhead turtles (Caretta caretta) in a tropical developmental habitat in Caribbean Panama. Approximately 65‐70% of the loggerhead turtles in Chiriqui Lagoon originate from South Florida nesting beaches, and the other 30‐35% originate from Mexico. Haplotype frequencies of the Chiriqui Lagoon loggerhead population are significantly different from those observed in the pelagic environment in the eastern Atlantic, and estimated nesting beach contributions to Chiriqui Lagoon are significantly different from values expected if recruitment were based solely on the size of nesting populations. These observations suggest that dispersal of loggerheads into benthic developmental habitats from the pelagic environment is not random. The occurrence of US and Mexican loggerheads in tropical developmental habitats has not been previously recognized. Exploitation and other mortality factors operating in the Caribbean area must be taken into account in demographic models and management plans for these two populations. This exploitation could be particularly important for the small, demographically vulnerable Mexican population and for other small populations for which no genetic data are currently available.

Acid preparation, at the Natural History Museum, London, of a turtle skull and jaw presented to the Museum of Geology, Sandown, Isle of Wight, England, by R. W. Harris in 1931, has revealed extremely derived palatal morphology previously undescribed in turtles. The specimen is described as a new genus and species, Sandownia harrisi, and is superficially similar to certain soft-shelled turtles (family Trionychidae) although the extensive secondary palate and extensive skull roof are previously unknown for this family. Other features of the skull suggest that it is not a trionychid but can be assigned to the Trionychoidea and that its closest affinities are with the members of the Trionychia (Carettochelyidae and Trionychidae). This specimen is one of the oldest known cryptodiran turtles that nests within the living families (the Polycryptodira). It suggests that the deep divergences among the living families of the Cryptodira occurred more than 110 million years ago.

A recently discovered fossil land tortoise (Testudines: Testudinidae) is described from the Pleistocene of Bermuda. Its morphology is sufficiently well preserved to allow assignment to the extinct North American genus Hesperotestudo . However, several features of this tortoise are unique and it is named Hesperotestudo bermudae sp. nov. A review of the phylogenetic relationships of the better known genera of the Testudinidae suggests that the affinities of Hesperotestudo lie with other North American tortoises ( Gopherus ) and not with Geochelone or other testudinines; thus, Hesperotestudo is reassigned to the Xerobatinae. This is at least the fifth documentation of a testudinid dispersing over open ocean to an oceanic island (the first for Hesperotestudo ) and it corroborates the hypothesis that members of this family are well suited to over-water dispersal.

We present phylogenetic analyses of both molecular and morphological data for the 23 major lineages of living turtles and seven key fossil taxa. Nearly 1 kilobase of cytochrome b sequence, 325 base pairs of 12S ribosomal DNA, and 115 morphological characters contained similar phylogenetic information, although each provided unique information on different nodes of chelonian history. A character-based combinability test (implemented in PAUP*) and a non- parametric test of taxonomic congruence indicated no strong evidence for heterogeneity among data sets, and we used a combined approach to estimate a final phylogeny of the major lineages of living turtles. This approach resulted in a very well-resolved tree, with only a few of the deep branches within the Cryptodira left as an unresolved polytomy. The addition of six relatively complete fossils chosen to help resolve this basal polytomy provided little added resolution to the tree and resulted in a sharp decline in bootstrap proportions for nodes near the fossils. Branch- length analysis and independent dates from the fossil record suggest that these unresolved nodes may represent a rapid radiation of the major cryptodiran lineages 90-120 million years ago. (Combined molecular and morphological data; fossil and recent phylogeny; mitochondrial DNA; starburst phylogeny; Testudines; total evidence.)

Thirteen new specimens in the collection of the American Museum of Natural History allow redescription of the lower Cretaceous side-necked turtle, Araripemys barretoi Price 1973. Araripemys is one of the three oldest pleurodires known for which the skeletal morphology can be completely described. The genus is incorporated into a phylogenetic analysis of pelomedusid (sensu lato) turtles. Examination of 35 skeletal characters in six living and nine extinct taxa suggest that there are four distinct clades in the Pelomedusidae (sensu lato). These are the Araripemydidae (including Araripemys and an undescribed genus from the same locality), the Pelomedusidae (restricted to the living genera Pelusios and Pelomedusa), the Bothremydidae (including at least five extinct genera) and the Podocnemidae (including the living genera Podocnemis, Peltocephalus and Erymnochelys, and a series of extinct genera). The hyperfamily name Pelomedusoides is available and accommodates these four families.

The first cryptodiran turtle with a pitted palate, Brachyopsemys tingitana gen. et sp. nov., is described on the basis of skulls and a lower jaw from the early Paleocene (Danian) of the Ouled Abdoun Basin, Morocco. The new taxon shares a number of apomorphic features with Sandownia harrisi from the Aptian of the Isle of White, England, Angolachelys mbaxi from the Turonian of Angola, and an unnamed turtle from the Albian Glen Rose Formation in Texas. A phylogenetic analysis provides evidence that they form a monophyletic clade which we name the Sandownidae fam. nov. The phylogenetic relationships of Sandownidae are problematic. Their affinities among the Eucryptodira remain uncertain; a well-preserved shell of a member of the family may be useful in determining relationships. The family appears to be a bottom-dwelling group that occurred in near-shore marine environments along the coast of the Atlantic across the Cretaceous-Tertiary boundary. Its evolutionary history is connected to the development of the Atlantic Ocean.

A new genus and species of podocnemidid pleurodire, Caninemys tridentata, is described on the basis of a skull collected by L.I. Price in 1962 from the late Miocene of Acre, Brazil. It is unique among podocnemidids (and all other turtles) in having greatly inflated maxillae, each with a ventral, toothlike process. Along with a midline process of the premaxillae, these processes form a tridentate condition in the upper triturating surface, also unique among podocnemidids but comparable to the condition in the kinosternid Claudius. This skull has previously been identified as the shell-based genus Stupendemys, but there are no associations supporting this assignment. The type specimens are separated by over 2000 km, and other large podocnemidid taxa are known from this time and region. Although relatively large with a condylobasal skull length of about 17 cm, Caninemys was probably about half the size of Stupendemys. Phylogenetic analysis of 63 skeletal characters provides evidence that this new ta...

— A character matrix of 39 characters for 14 supregeneric categories of living and extinct turtles was examined using PAUP 2.41 and 3.0L. The Branch and Bound algorithm found a single most parsimonious cladogram of 55 steps, consistency index of 0.709, retention index of 0.848 and a rescaled consistency index of 0.601. The cladogram is identical to that proposed by Gaffney and Meylan (1988). The Pleurodira and Cryptodira are each shown to be monophyletic and are supported by synapomorphies involving complex structures of the basicranium and adductor musculature. These synapomorphies are judged to be relatively well-tested homologies. A paraphyletic Cryptodira occurs in 18% of 38 equally parsimonious trees 57 steps in length, but these trees are based on characters, such as absence of pterygoid teeth, that are susceptible to homoplasy in amniotes. We re-iterate the notion that it is better to choose fewer, well-analysed characters than large numbers of poorly analysed characters.

The hawksbill turtle (Eretmochelys imbricata), listed since 1996 by the IUCN as Critically Endangered and by the Convention on International Trade in Endangered Species (CITES) as an Appendix I species, has been the subject of attention and controversy during the past 10 years due to the efforts of some nations to re-open banned international trade. The most recent debate has centred on whether it is appropriate for Cuba to harvest hawksbills from shared foraging aggregations within her national waters. In this issue of Molecular Ecology, Bowen et al. have used molecular genetic data to show that such harvests are likely to have deleterious effects on the health of hawksbill populations throughout the Caribbean.

Testudines is an order of reptilian tetrapods commonly called turtles (including tortoises and terrapins). All fossil and living members of the group have a shell that encloses both of the limb girdles. The group has its origins in the Triassic and is now represented by 13 living families, many of which contain species in danger of extinction. Keywords: turtles; tortoises; terrapins; chelonians; Testudinata

A fragmentary radius of Hesperotestudo bermudae from an underwater cave deposit in Bermuda is only the second known specimen of the species. The exact provenance and age of the specimen have been lost, but the record provides additional evidence that there was a population of endemic tortoises on Bermuda in the Pleistocene.

The hawksbill turtle (Eretmochelys imbricata), listed since 1996 by the IUCN as Critically Endangered and by the Convention on International Trade in Endangered Species (CITES) as an Appendix I species, has been the subject of attention and controversy during the past 10 years due to the efforts of some nations to re-open banned international trade. The most recent debate has centred on whether it is appropriate for Cuba to harvest hawksbills from shared foraging aggregations within her national waters. In this issue of Molecular Ecology, Bowen et al. have used molecular genetic data to show that such harvests are likely to have deleterious effects on the health of hawksbill populations throughout the Caribbean.

Fossil soft-shelled turtles (family Trionychidae) are described from three localities in the Lake Turkana Basin, Kenya. Data on trionychid specimens from these three localities, Pliocene of Kanapoi and Lothagam, and Pleistocene of Koobi Fora, are supplemented with data from Karungu and Chemeron, Kenya, Omo, Ethiopia, and the Chiwondo Beds of Malawi. With the exception of three specimens from Koobi Fora, which probably represent Trionyx triunguis, all of these East African fossil trionychids can be referred to the subfamily Cyclanorbinae. Three of four living cyclanorbine species in Africa, Cyclodermafrenatum, Cyclanorbis elegans and C. senegalensis, are preserved as fossils in the Lake Turkana basin. Additionally, three extinct species are now known from the Neogene of East Africa. Cycloderma victoriae Andrews was described from the Miocene Karungu beds of Kenya in 1914. Two additional cyclanorbines, C. debroinae and Cyclanorbis turkanensis, both from Pliocene localities in the Lake Turkana basin, are described in this report. Identification of these two new fossil species brings to seven the total number of cyclanorbines known from Africa. Five of these occur in the Lake Turkana Basin. This high diversity may reflect the historical association of this basin with both other Rift Valley lakes and with the greater Nile drainage system, and periodic transgressions and regressions within the basin itself. The distribution of cyclanorbine trionychids in Africa is congruent with those of freshwater fishes and is completely explained using a vicariant hypothesis.

The described fossil testudinids from the Miocene of Africa are reviewed. Geochelone stromeri sp. nov. is described from Lower Pliocene (Langebaanweg) and Miocene (Namib) specimens. Kinixys erosa, an extant species, is reported from Songhor Hill. Chersina sp. is reported from Arrisdrift. Impregnochelys pachytectis gen. et sp. nov. is described from Rusinga Island, Kenya, and is unique in having the anterior shell opening orientated ventrally and in having struts on the internal surface of the neurals, but shares with Kinixys a unique epiplastron shape, a high number of axillary scutes and unique orientation of the head of the femur.