Current Herpetology

This study investigated the frequency and distribution of reports of free-living green iguanas (Iguana iguana), a Neotropical lizard, in Hong Kong. We found 44 reports of I. iguana, of which 93% were removed from the wild. Thirty-nine reports were records kept by one non-government organization, one report from a government agency, and four reports from community members. Reports were sporadic between 2002 and 2011, but have occurred in every calendar year since 2012, predominately during March, July and October. Report locations were distributed broadly across 16 administrative districts, including heavily developed city areas, indicative of released or escaped pets being the source. Although there was evidence of two individuals living in one locality, we found no major concentrations of reports to indicate established populations. Nevertheless, these data should not be assumed benign since some established populations of I. iguana elsewhere have only become evident following prolonged periods of sporadic reports. It is therefore plausible that emerging reports in Hong Kong may represent a contemporary invasion presently under way. Public reporting of I. iguana plays an important role in preventative invasive species management. However, we also found cases where I. iguana reported as free-living were more likely the same captive I. iguana, highlighting potential errors with community science.

This study provides the first morphological data from a female specimen of the recently described Stoliczkia vanhnuailianai from Mizoram, Northeast India. Based on a new individual collected from a stream habitat around 80 km northwards from the type locality, we provide an expanded summary of diagnostic key characters of the species, additional notes on the habitat, and new genetic data for this rare snake.

In the Ogasawara Islands adhesive traps are the primary means of controlling non-native Anolis carolinensis. If the types of tree trunks most frequently used by this lizard are identified, trapping efficiency can be improved by concentrating traps at such points. To analyze selectivity by trunk diameter, the diameters of 270 tree trunks used by the lizards and 1,024 tree trunks in the study area were measured. The analysis indicated the lizards avoided trunks of 1 cm or less in diameter. On the other hand, trunks with diameters over 2 cm appeared to be used randomly, regardless of diameter size. The diameter class distribution of trees varies by region and by forest. The range of tree trunk diameters commonly used by lizards is thus expected to vary by location. It would be advantageous to develop a capture technique that is effective for trunks and branches of various diameters.

Oral morphological features and the diet of the tadpoles of Polypedates maculatus were described in this study. The tadpoles were collected from various water bodies of the state of Odisha over three consecutive breeding seasons (2018–2020). Oral and internal buccal characters were analysed independently for Gosner developmental stages 25 to 46. The upper labium has four labial tooth rows with a medial gap in the three rows proximal to the mouth, whereas the lower labium has three rows with a medial gap in the row proximal to the mouth. The order of length of denticle rows is A2>P1>P2>A1>P3>A3>A4 with a dental formula of A4(3)/P3(1). The food spectrum of the tadpoles included mostly phytoplanktons (represented by six classes and 51 genera) followed by zooplankton (two classes and four genera). Three Bacillariophyceae genera (Navicula, Pinnularia, and Synedra) contributed most of the gut contents. Scenedesmus was the major food items in Chlorophyceae family and had the highest numeric frequency (7.63%) among all the food items. Other prevalent food items included Zygnematophyceae, Cyanophyceae, Euglenophyceae, Rotifera, Ulvophyceae and Copepoda.

Hynobiid salamanders of the genus Onychodactylus are known to possess palmar and tarsal black tubercles or asperities during the breeding season, which were once considered male-specific characters used for spawning activity. However, such tubercles and asperities have also been observed in females and are not always developed in breeding individuals; thus, their functions remain unclear. In this study, we investigated the developmental process of the tubercles and asperities in two Onychodactylus species in the Chugoku Mountains. We found that these traits appear rapidly immediately before the start of spawning. Tubercles and asperities were also observed in females, in which they showed a similar temporal developmental pattern to that observed in males; thus, they may be adaptive traits for migration to underground spawning sites or for breeding activity at these sites. In the Chugoku Mountains, O. kinneburi and O. japonicus are known to share breeding sites for spawning, but their reproductive isolation mechanism remains unknown. In the course of our survey, we found a temporal gap in breeding season between the two species, which may be involved in premating reproductive isolation.

The Taiwan beauty snake, Elaphe taeniura friesi, has established a stable population in the central part of Okinawajima Island, and there are concerns about the negative effects of the snakes' predation on the native fauna. Thus, we examined the stomachs of 239 E. t. friesi specimens collected on Okinawajima Island from July 2018 to November 2019. Stomach contents were identified to the species level whenever possible based on morphological observations and/or DNA analyses. Of the 239 snake specimens, 39 (12 males, 16 females, and 11 juveniles) had contents in their stomach, including 67 prey items, 75% of which were mammals (Muridae and Soricidae) and the rest of which were birds (Pycnonotidae, Cisticolidae, and Columbidae). Rattus rattus occurred most frequently; 25 of the 39 snakes examined had this species in their stomachs. All avian prey items detected were nestlings and eggs. Twelve snakes had multiple prey items in their stomach, including in most cases either nestlings of passerine birds or infants or subadults of R. rattus. Therefore, E. t. friesi is an endotherm consumer that occasionally preys on nestlings and infant rats. These food habits suggested that E. t. friesi uses various habitats, from the humus layer on the ground to the branches of trees, for foraging. Several endangered endemic rodent and bird species exist in the northern area of Okinawajima Island; thus, our results provide a warning about potential negative impact on such animals when E. t. friesi expands its range to the northern part of the island.

Duttaphrynus hololius is an uncommon species of toad presumably endemic to peninsular India. Since the original description, no records originated from the type locality “Malabar” or the Western Ghats. At the same time, several authors reported it from the other parts of peninsular India and the Eastern Ghats. This led to confusion and made previous workers question the true origin of the type locality of D. hololius. Some works also predict the distribution of this species based on niche modelling techniques. This work provides new records from the Western Ghats and vicinity for the first time after its description with new molecular data. We also discuss pre-colonial and colonial “Malabar” and predict the suitable range of D. hololius under different climatic scenarios based on the further analysis carried out herein using the species distribution modelling approach.

In the Kitayama-region of Kyoto city, two types of the brown frog Rana tagoi occur syntopically. They are populations of small and large frogs that do not overlap in adult body size and proved to be heterospecific genetically. In order to clarify the cause and significance of this body size difference, we studied the growth pattern in the two populations. For comparison, we also examined an allopatric population of R. tagoi from Shishiga-tani, Kyoto, which is genetically very close to the large type, and occurs without co-inhabiting different sized individuals. We examined sections of periosteal bones, and counted the number of LAGs in the bone to determine ages of individuals. We used logistic model and estimated instantaneous growth rate and asymptotic size, to describe growth pattern. Each of the two types from Kitayama exhibited unique growth pattern, and the Shishiga-tani population showed a growth pattern intermediate between those of the two types in asymptotic size. Difference in size of two types is discussed with relation to the character displacement.

Studies of elevational variation in diets in lizards have often found shifts in diet composition among elevations. Herein, we studied the diets of Sceloporus variabilis from six populations found in a variety of habitats along an elevational gradient (3–1900 m) in Puebla and Veracruz, Mexico. Diets of S. variabilis for the six populations were similar at the order level, with hymenopterans and coleopterans being the most important prey items. However, the specific taxa at the family or genus level varied among the six populations. The presence of plant material in diets varied among the six populations, with the two lowest elevation populations and the highest elevation population containing the most of this material.

Observations of the osteological features of malformations in lizards are currently limited. In examinations of ca. 1,300 Scincella specimens, one Scincella lateralis specimen and three S. boettgeri specimens were observed to have malformed digits, i.e., ectrodactyly. Each of these specimens had a malformation in only one limb. One S. lateralis specimen lacked digits I–III of manus, and three S. boettgeri specimens lacked digits I, II, or I and II of pedes. Micro-computed tomography scanning revealed that the phalanges and metacarpals of digits I–III were absent in the malformed S. lateralis specimen, whereas the malformed S. boettgeri specimens lacked all phalanges for externally absent toes but had five metatarsals, despite these being shorter in the absent toes than those in normal toes. Although malformed limbs have been reported previously in lizards, this is the first report based on osteological descriptions. Some genera of Scincidae include species that have undergone phylogenetic reduction of their digits. In such species, the developmental order of the phalanges and metacarpals/metatarsals is well-known from embryological studies. With reference to this developmental mechanism, we also discuss the assumed development of the malformed specimens observed in this study.