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Herein we briefly provide a background context for and summary overview of the articles comprising this special issue of the Southeastern Naturalist on Macrochelys spp. (alligator snapping turtles). We also make a case for standardization in collecting and reporting morphometric data on these species, clarify the current taxonomic status within the genus, provide updated information on the distribution of Macrochelys in the US, and include a current bibliography and categorical analysis over time of the rapidly growing collection of literature focused on these iconic turtles. [ABSTRACT FROM AUTHOR]

The lingual lures of Macrochelys (alligator snapping turtles) are believed to be the only prey-capturing lures within the mouths of modern reptiles. To date, no formal assessment of lure condition in Macrochelys has been published, and few researchers record lure data. Herein, we report damaged or missing lures from 25 Macrochelys temminckii (Alligator Snapping Turtle; 7 adults, 18 juveniles) from a sample of more than 2000 lure assessments in 4 states, indicating this is a rare occurrence. We also describe lingual lure color observed in these assessments and introduce standardized terminology and color categories. We suggest researchers record data on the condition and coloration of the lingual lure to further our understanding of this ecological and evolutionary adaptation. [ABSTRACT FROM AUTHOR]

Alligator snapping turtles (genus Macrochelys) are the largest freshwater turtles in North America. Despite strong interest in their conservation, we still lack a comprehensive understanding of their natural history, including behaviors associated with terrestrial activity. We reviewed the literature and solicited unpublished observations of terrestrial movements of these highly aquatic turtles. We compiled 206 observations of terrestrial activity from 9 states. The majority of observations were associated with nesting behavior. Observations expanded our knowledge regarding the spatial extent and timing of terrestrial movements and the nesting season. In addition, we compiled observations of terrestrially foraging animals, as well as males and juveniles traveling overland and crossing roads. Collectively, this information clarifies the extent of terrestrial movement by Macrochelys, behaviors that should be considered in conservation plans. [ABSTRACT FROM AUTHOR]

We report nest success for 16 Alligator Snapping Turtle nests oviposited at Black Bayou Lake National Wildlife Refuge in 2008 and 2009. We split each clutch into 2 portions for field and laboratory incubation. The field portion was protected from mammalian depredation. For each nest, we report both pipping and hatching success. Our total observed levels of pipping and hatching success were 55.9% and 47.7%, respectively. We obtained a hatching success rate of 85.8% in the lab. Reasons for the difference in hatching success between the field and lab included both abiotic and biotic factors in the nest environment, such as flooding, temperature, and invertebrate predators. [ABSTRACT FROM AUTHOR]

We collected reproductive data from six female Deirochelys reticularia miaria in northeastern Louisiana that were collected in January 1999, June 2001, and May of both 2002 and 2003. One female collected in late January was dissected and found to contain two size classes of enlarged ovarian follicles. Five additional females collected on land in May or June were all gravid; three of them were caught while digging a nest. Mean clutch size was 10.6 and mean egg size was 37.68 × 22.88 mm, with a mass of 11.69 g. The mean incubation period for 32 eggs was 84 days, and hatchling measurements were mean carapace length of 31.67 mm and mass of 8.32 g. [ABSTRACT FROM AUTHOR]

We describe the subsistence exploitation of an entire turtle fauna in Esmeraldas Province, Ecuador. We collected firsthand accounts and witnessed a number of capture techniques used by rural Afroecuadorian and Chachi inhabitants of the Cayapas-Santiago river basin. The diversity of techniques indicated a practical knowledge of the ecology of the species. Chelydra acutirostris, Kinosternon leucostomum, Rhinoclemmys annulata, melanosterna, and R. nasuta were captured and eaten. Poziando involved cleaning pools in a stream bed during the relatively dry season by removing live plants, organic detritus, and then seining with baskets; we observed R. melanosterna and K. leucostomum captured in this way. Pitfall traps baited with fruit were used to catch R. melanosterna during forays on land. Basket traps ("canasto tortuguero") with a wooden slat funnel across the opening are floated with balsa lashed to the sides. Banana or Xanthosoma leaf bait in the basket traps caught R. melanosterna, R. nasuta, and K. leucostomum. Marshy areas were probed for R. melanosterna and K. leucostomum. Direct capture by hand was also common. Turtles were relished as food items; all turtles captured were consumed, usually in soup or stew. Use of turtles for food in the region was pervasive, perhaps because fish and game populations were depleted. [ABSTRACT FROM AUTHOR]

Nest depredation is a major source of mortality in many turtle populations. Although turtle life histories may have evolved with relatively high levels of nest depredation, present-day levels may be negatively impacting populations that are already declining. This degree of depredation may be problematic for species such as Macrochelys temminckii (Alligator Snapping Turtle), which has relatively low reproductive output for a large turtle, yet little is known about depredation of M. temminckii nests. We constructed 90 artficial M. temminckii nests in 2008 and 2009 at Black Bayou Lake National Wildlife Refuge in Louisiana to identify nest predators and elucidate patterns of nest depredation. All artficial nests were depredated, with Procyon lotor (Raccoon), and Dasypus novemcinctus (Nine-banded Armadillo) being the two most common nest predators. Other predators included Lontra canadensis (Northern River Otter), Didelphis virginiana (Virginia Opossum), and Lynx rufus (Bobcat). Nest depredation is a major threat to Alligator Snapping Turtles at this site and may be limiting recruitment in this population. [ABSTRACT FROM AUTHOR]

The Alligator Snapping Turtle (Macrochelys temminckii) is a species of conservation concern across its range due to past commercial harvest for consumption. Northern Louisiana was originally surveyed in the 1980s, but the survey data were not compiled and published. After almost 40 years, we resurveyed the region to validate the historic data as well as provide current data on the distribution of Alligator Snapping Turtles. From the 1980s, we provide demographic data for 300 Alligator Snapping Turtles collected from 17 Louisiana parishes. From 2018–2020, we captured and measured 62 Alligator Snapping Turtles from 19 trapping sites. We recommend continued surveying and monitoring efforts in Louisiana to track populations during the post-commercial–harvest period. [ABSTRACT FROM AUTHOR]

We report emergence dates for 38 alligator snapping turtle (Macrochelys temminckii) hatchlings from 6 naturally incubated nests laid during the 2008 and 2009 nesting seasons in northeastern Louisiana. Per capita emergence success for 2008 and 2009 combined was 19.5%. Hatchling emergence occurred from 28 August to 25 September and was asynchronous for 80% of nests that had multiple hatchlings emerge, with emergence duration as long as 12 days. We found no evidence of delayed emergence; some hatchlings may remain in the nest for up to 3 weeks before successfully emerging. [ABSTRACT FROM AUTHOR]

I describe terrestrial foraging behavior in Trachemys scripta elegans (Red-eared Slider) and Graptemys pseudogeographica kohnii (Mississippi Map Turtle) two species of semiaquatic turtles. I observed specimens of Red-eared Slider on two occasions in two different locations climbing onto the bank of a stream and consuming grass blades (Luziola fluitans [Southern Watergrass] and Eragrostis hypnoides [Teal Lovegrass]), which were swallowed when the turtles returned to the water. These observations included both adult males and females. In addition, I observed on one occasion two juvenile Mississippi Map Turtles leave the water and forage on plants on a stream bank also used by Red-eared Sliders. Individuals of Mississippi Map Turtles passed by grass and consumed the sprouts of a dicot (Ludwigia decurrens [Wingleaf Waterprimrose] and/or Pentodon pentandrus [Hale's Pentodon]). [ABSTRACT FROM AUTHOR]

Between 1997 and 2001, we observed nesting behavior following oxytocin-induced oviposition in 10 three-toed box turtles. Oviposition preceded nesting behavior by 0.5-17 days. Three turtles oviposited subsequent clutches (without oxytocin induction) a mean of 30 days after the oxytocin injections but only 22 days after they constructed empty nests. The mean internesting interval was 21 days between consecutive ovipositions without oxytocin induction by these 3 females in the same and subsequent seasons. [ABSTRACT FROM AUTHOR]

Larvae of the phorid fly Megaselia scalaris were in eggs in a naturally incubated nest of an alligator snapping turtle (Macrochelys temminckii). It appears that these larvae contributed to failure of this nest. Infestation by phorid larvae has been reported previously for eggs and nests of multiple species of turtles, but has not been reported from M. temminckii. [ABSTRACT FROM AUTHOR]

Few long-term demographic studies have been conducted on freshwater turtles of South America, despite the need for this type of inquiry to investigate natural variation and strengthen conservation efforts for these species. In this study, we examined the variation in demography of the Chocoan River Turtle (Rhinoclemmys nasuta) based on a population from an island locality in the Colombian Pacific region between 2005 and 2017. We calculated survival, recapture, and transition probabilities, and the effects of stream substrate and El Niño–Southern Oscillation (ENSO) phases (El Niño, Neutral, La Niña) on these variables using a multi-state model. We found differences in survival probabilities between ENSO phases, likely as a consequence of an increase in flood events. In addition, we found support for survival being greater in muddy streams than rocky streams, possibly because it is easier to escape or hide in mud substrates. Recapture probabilities varied by life stages; differences in the probability of recapture between size classes were associated with the high fidelity to territories by adults. The present increases in frequency and severity of El Niño and La Niña may exacerbate the consequences of climatic regimes on natural populations of turtles by increasing the mortality caused by drastic phenomena such as floods. [ABSTRACT FROM AUTHOR]

Macrochelys temminckii (Alligator Snapping Turtle) were commercially harvested for consumption, and Louisiana was the last state to ban this commerce. There are no demographic studies on healthy populations within the state. We conducted trapping surveys at Black Bayou Lake National Wildlife Refuge near Monroe, LA, from 2004 to 2020. We captured 90 individual Alligator Snapping Turtles over 17 years. We compared survey data between the 2004–2005 survey period and the 2019–2020 survey period to estimate changes in demography. We found the population to be stable, but the low number of juveniles captured raises concerns for the future of the population. Continued monitoring is recommended to evaluate the stability of the population. [ABSTRACT FROM AUTHOR]

With the conservation status of Macrochelys (alligator snapping turtles) being examined at the national level, our objective was to compile categorical data on threats from anthropogenic interactions. We included information from (1) author-collected anecdotes on human–turtle interactions and (2) radiographs to assess the prevalence of ingested fishing hooks. We placed 173 interactions involving 192 incidents into 9 IUCN threat categories and found bycatch involving fish hooks to be 4 times more numerous than the second-most numerous threat, turtle persecution. Fishing bycatch resulted in a high proportion of turtle mortalities (39%), and bycatch incidents in several cases preceded the highest-mortality threat (53%), persecution of individuals involving shooting or blunt trauma. We recommend fishing bycatch-mitigation measures and educational efforts to help conserve Macrochelys. [ABSTRACT FROM AUTHOR]

The article offers information on geographical distribution of several species of turtles located in northern Louisiana. Species discussed include Apalone Mutica, Apalone Spinifera, and Chelydra Serpentina. It mentions that a number of distributional reports with specific localities have been published that have significantly filled in our parish-level understanding of herpetofaunal distribution within the state.

Chicken turtles (Deirochelys reticularia) are generally characterized as having atypical reproductive characteristics relative to other sympatric emydids. However, the comparatively understudied western chicken turtle (D. r. miaria) has been shown to exhibit some reproductive characteristics that differ from the other subspecies. Therefore, we examined clutch and egg sizes from six D. r. miaria (13 clutches) in Oklahoma and compared the results to values that have been reported for the other two subspecies. Females nested up to three times per year, with clutches ranging from 8-13 eggs per clutch (mean = 10.9). The eggs were 19.4-25.3 mm wide (mean = 22.2 mm). These values are greater than the means reported for the other subspecies, but the differences were not statistically significant. [ABSTRACT FROM AUTHOR]

We collected data on several aspects of the reproductive biology of the Chocoan River Turtle (Rhinoclemmys nasuta) as part of a long-term demographic study (2005-2015), along the Pacific coast of the department of Valle del Cauca in Colombia. We palpated 659 females and found 77 gravid, with two peaks in the proportion of females gravid, one between May and June, and another from October to December; there was a significant correlation between the monthly proportion gravid and the monthly amount of precipitation (Spearman rank correlation rs = 0.60, P < 0.05). We obtained 13 eggs (mean length = 63.8 mm, mean width = 35.4 mm, mean weight = 45.8 g). Using egg volume as a general indicator of size, there was no significant relationship with female size. To induce oviposition, oxytocin, prostaglandin, or a combination of the two was injected into 37 gravid females with a success rate of 48.6%. We determined the duration of incubation for two individuals as 133 and 135 days. With this information, we fill some gaps in the knowledge of reproductive ecology of this species; however, the sample size is very low and primarily comes from a single insular population and therefore it is important to continue studies on aspects of reproductive ecology such as those evaluated in this study and other topics like sex determination. [ABSTRACT FROM AUTHOR]

The article reports on the distribution records for herpetofauna of Louisiana as of December 2015. These include Brown Anole at Buckhorn Wildlife Management Area (WMA), Rio Grande Chirping Frog found at Alexander State Forest WMA, Mole Salamander at Boeuf WMA, and Timber Rattlesnake at Sicily Island Hills WMA.

Dunns' mud turtle Kinosternon dunni is recognized only from a few localities in the drainages of the San Juan, Baudó and Docampadó Rivers in Chocó, Colombia. We report on the occurrence of the species in three new localities in a different drainage, two in the Atrato River drainage, which flows into the Caribbean Sea, and a third locality in the Gulf of Urabá, in the Colombian Caribbean. These new records extend the range of the species approximately 367 km to the north of the closest previous confirmed record. [ABSTRACT FROM AUTHOR]