We follow a biological invasion model that consists of a series of five consecutive obligatory stages, concluding with stages 4a and 5 (i.e., widespread = invasive species). The State of Florida is infamous for having the most introduced (stages 2–5) amphibians and reptiles in the United States. However, there is disagreement regarding their numbers as well as identification in some cases. Unverified claims of species being introduced (stage 2), or established (stages 3–5) without evidence (i.e., a voucher specimen or photograph) are prevalent in the literature. It is crucial to provide data on all known non-indigenous herpetofaunal species via vouchers to help keep numbers of species consistent, accurately identify species, document when and where a particular species is found, and identify the invasion pathway and current invasion stage of each species. In this study, we use vouchers to confirm interceptions and introductions of all known non-indigenous amphibians and reptiles in Florida from 1863 through 2010, provide a list of these species along with their invasion pathways and current ecological status (i.e., invasion stage), and provide a species account for each newly confirmed species. We include species that were previously reported in the literature but lacking an associated voucher and provide greater details on previously reported species and those species whose invasion stage has been upgraded to established (stages 3–5). Based on nearly two decades of field work along with examination of museum records and literature, we confirm three intercepted and 137 introduced amphibian and reptile taxa in Florida. Of these, 56 are established (i.e., reproducing; stages 3–5), including three frogs, four turtles, one crocodilian, 43 lizards, and five snakes. Of 149 total independent introduction pathways (i.e., including a different pathway one time only for each taxon) for the 140 total non-indigenous taxa above, two (1.34%) are related to the biological control pathway, four (2.68%) to the zoo pathway, 18 (12.08%) to the cargo pathway, and 125 (83.89%) to the pet trade pathway. Florida now ranks as having the largest number of established non-indigenous herpetofaunal species in the entire world. Despite current state laws that make it illegal to release any non-indigenous animal in Florida without first obtaining a permit from the Florida Fish and Wildlife Conservation Commission, enforcement is difficult, and no person has ever been prosecuted for the establishment of a non-indigenous animal species in Florida. Because current state and federal laws have not been effective in curtailing the ever-increasing number of illegal introductions, laws need to be modified and made enforceable. At the very least, those responsible for introductions should be held accountable for compensation to clean up (= extermination) of those species for which they are responsible. Lastly, we strongly support the creation of an Early Detection and Rapid Response program to quickly identify newly found introduced species for eradication attempts. This paper will also serve as a baseline to document future introductions.

No abstract

For primates and other mammals moving on relatively thin branches, the ability to effectively adopt both above-and below-branch locomotion is seen as critical for successful arboreal locomotion, and has been considered an important step prior to the evolution of specialized suspensory locomotion within our Order. Yet, little information exists on the ways in which limb mechanics change when animals shift from above-to below-branch quadrupedal locomotion. This study tested the hypothesis that vertical force magnitude and distribution do not vary between locomotor modes, but that the propulsive and braking roles of the forelimb change when animals shift from above-to below-branch quadrupedal locomotion. We collected kinetic data on two lemur species (Varecia variegata and Lemur catta) walking above and below an instrumented arboreal runway. Values for peak vertical, braking and propulsive forces as well as horizontal impulses were collected for each limb. When walking below branch, both species demonstrated a significant shift in limb kinetics compared with above-branch movement. The forelimb became both the primary weight-bearing limb and propulsive organ, while the hindlimb reduced its weight-bearing role and became the primary braking limb. This shift in force distribution represents a shift toward mechanics associated with bimanual suspensory locomotion, a locomotor mode unusual to primates and central to human evolution. The ability to make this change is not accompanied by significant anatomical changes, and thus likely represents an underlying mechanical flexibility present in most primates.

Vertical climbing is an essential behavior for arboreal animals, yet limb mechanics during climbing are poorly understood and rarely compared with those observed during horizontal walking. Primates commonly engage in both arboreal walking and vertical climbing, and this makes them an ideal taxa in which to compare these locomotor forms. Additionally, primates exhibit unusual limb mechanics compared with most other quadrupeds, with weight distribution biased towards the hindlimbs, a pattern that is argued to have evolved in response to the challenges of arboreal walking. Here we test an alternative hypothesis that functional differentiation between the limbs evolved initially as a response to climbing. Eight primate species were recorded locomoting on instrumented vertical and horizontal simulated arboreal runways. Forces along the axis of, and normal to, the support were recorded. During walking, all primates displayed forelimbs that were net braking, and hindlimbs that were net propulsive. In contrast, both limbs served a propulsive role during climbing. In all species, except the lorisids, the hindlimbs produced greater propulsive forces than the forelimbs during climbing. During climbing, the hindlimbs tends to support compressive loads, while the forelimb forces tend to be primarily tensile. This functional disparity appears to be body-size dependent. The tensile loading of the forelimbs versus the compressive loading of the hindlimbs observed during climbing may have important evolutionary implications for primates, and it may be the case that hindlimb-biased weight support exhibited during quadrupedal walking in primates may be derived from their basal condition of climbing thin branches.

The Alligator Snapping Turtle, Macrochelys temminckii, is a large, aquatic turtle limited to river systems that drain into the Gulf of Mexico. Previous molecular analyses using both mitochondrial and nuclear DNA suggested that Macrochelys exhibits significant genetic variation across its range that includes three distinct genetic assemblages (western, central, and eastern = Suwannee). However, no taxonomic revision or morphological analyses have been conducted previously. In this study, we test previous hypotheses of distinct geographic assemblages by examining morphology, reanalyzing phylogeographic genetic structure, and estimating divergence dating among lineages in a coalescent framework using Bayesian inference. We reviewed the fossil record and discuss phylogeographic and taxonomic implications of the existence of three distinct evolutionary lineages. We measured cranial (n=145) and post-cranial (n=104) material on field-captured individuals and museum specimens. We analyzed 420 base pairs (bp) of mitochondrial DNA sequence data for 158 Macrochelys. We examined fossil Macrochelys from ca. 15-16 million years ago (Ma) to the present to better assess historical distributions and evaluate named fossil taxa. The morphological and molecular data both indicate significant geographical variation and suggest three species-level breaks among genetic lineages that correspond to previously hypothesized genetic assemblages. The holotype of Macrochelys temminckii is from the western lineage. Therefore, we describe two new species as Macrochelys apalachicolae sp. nov. from the central lineage and Macrochelys suwanniensis sp. nov. from the eastern lineage (Suwannee River drainage). Our estimates of divergence times suggest that the most recent common ancestor (MRCA) of M. temminckii (western) and M. apalachicolae (central) existed 3.2-8.9 Ma during the late Miocene to late Pliocene, whereas M. temminckii-M. apalachicolae and M. suwanniensis last shared a MRCA 5.5-13.4 Ma during the mid-Miocene to early Pliocene. Examination of fossil material revealed that the fossil taxon M. floridana is actually a large Chelydra. Our taxonomic revision of Macrochelys has conservation and management implications in Florida, Georgia, and Alabama.

The living sloths are the most suspensory of all extant mammals, and therefore represent ideal models for investigating the effects that suspensory behaviours have on bone and joint morphology. While the anatomy and kinematics of sloths are well known, no research has reported kinetic patterns of sloth locomotion. This study examines peak force patterns generated by the two‐toed sloth Choloepus didactylus during below branch quadrupedal walking to infer how kinetic patterns of sloths compare to data reported on non‐human primates. Values for vertical, fore‐aft, and mediolateral peak forces were collected for the forelimb and hind limb, and analyses between the magnitude and timing of these peaks were compared between forelimbs and hind limbs. Patterns and timing of fore‐aft peak forces were similar between sloths and non‐human primates, and were characterized by first a propulsive force as the limb first made contact with the support followed by braking force prior to lift‐off. Similarly, both sloths and primates demonstrate a medially directed force bias onto the substrate during below branch quadrupedal locomotion, although the magnitude observed in sloths exceeds values reported in primates. Peak vertical forces applied by the forelimbs and hind limbs of sloths were not statistically different in magnitude from each other. Data from this study indicate the forelimbs and hind limbs of sloths are functioning similarly to each other during below branch quadrupedal locomotion, and that forelimb‐biased weight support, the pattern typical of primates, is not a mechanical requirement of suspensory locomotion across all mammals. These findings provide important information about the mechanical necessities of below branch movement, and data from this study should be used when considering mechanical convergence among suspensory taxa and the interpretation of suspensory limb adaptations in the fossil record.

During quadrupedal walking, most primates utilize diagonalsequence diagonal-couplet gaits, large limb excursions and hindlimb-biased limb loading. These gait characteristics are thought to be basal to primates, but the selective pressure underlying these gait changes remains unknown. Some researchers have examined these characteristics during vertical climbing and propose that primate quadrupedal gait characteristics may have arisen due to the mechanical challenges of moving on vertical supports. Unfortunately, these studies are usually limited in scope and do not account for varying strategies based on body size or phylogeny. Here, we test the hypothesis that the spatiotemporal gait characteristics that are used during horizontal walking in primates are also present during vertical climbing irrespective of body size and phylogeny. We examined footfall patterns, diagonality, speed and stride length in eight species of primates across a range of body masses. We found that, during vertical climbing, primates slow down, keep more limbs in contact with the substrate at any one time, and increase the frequency of lateral-sequence gaits compared with horizontal walking. Taken together, these characteristics are assumed to increase stability during locomotion. Phylogenetic relatedness and body size differences have little influence on locomotor patterns observed across species. These data reject the idea that the suite of spatiotemporal gait features observed in primates during horizontal walking are in some way evolutionarily linked to selective pressures associated with mechanical requirements of vertical climbing. These results also highlight the importance of behavioral flexibility for negotiating the challenges of locomotion in an arboreal environment.

Locomotor diversity has meant many different things depending on the subject area or investigator. While no concrete definition of locomotor diversity is currently available, this has not stopped researchers from making a number of assertions about the underlying mechanisms that determine whether a species will have high or low locomotor diversity. Some of these claims include that: (1) arboreal primates demonstrate higher locomotor diversity than terrestrial species; (2) anatomically generalized and small‐bodied primates demonstrate higher locomotor diversity than anatomically specialized and large‐bodied taxa; and (3) primates demonstrate higher locomotor diversity compared to non‐primate mammals. None of these claims have been tested in any sort of comparative framework. Using previously published locomotor repertoire data from 110 mammalian species, this study co‐opted the Shannon–Wiener diversity index to calculate a singular measure of locomotor diversity. Phylogenetic analyses of these locomotor diversity indices reveal that within primates, small‐bodied species demonstrate greater locomotor diversity than large‐bodied taxa. However, this effect becomes non‐significant when accounting for differences in substrate‐use (i.e. arboreal vs. terrestrial). Anatomical specialization has no effect on locomotor diversity in primates. Furthermore, primates do not inherently have greater locomotor diversity than other mammalian taxa. Findings from this study suggest that movement on arboreal substrates requires all mammals, regardless of taxonomic affiliation, to demonstrate high locomotor diversity. These data further highlight the challenges faced by arboreal animals and raise the possibility that being able to switch fluidly and frequently between many different locomotor modes may be advantageous for animals moving in an arboreal milieu.