The British Herpetological Society

The Herpetological Journal is the Society's prestigious quarterly scientific journal. Articles are listed in Biological Abstracts, Current Awareness in Biological Sciences,Current Contents, Science Citation Index, and Zoological Record.

 ISSN 0268-0130

2020 Impact Factor for the Herpetological Journal is 0.862

Early Publication Early Publication

This folder contains papers which have been formatted ready for publication but which have not yet been compiled into an HJ edition.

pdf 01.Potential distribution of hybrids between Crocodylus acutus and Crocodylus moreletii on the Mexican Pacific coast outside the natural hybridisation zone


Open Access

pp. 93-101


Authors:  Gerardo J. Soria-Ortiz, Patricia G. García-Navarrete, Leticia M. Ochoa-Ochoa & Armando Rincón-Gutiérrez


Abstract: In Mexico, Crocodylus acutus is widely distributed along the Pacific coast, while C. moreletii occurs on the Gulf of Mexico. Both species converge in the Yucatán peninsula where natural hybridisation is reported, and later it was also reported in the Gulf of Mexico. Unfortunately, due to translocations and stochastic events, currently there are hybrids of both species on the coast of Oaxaca and Guerrero. In this study, we evaluated the potential colonisation areas of the hybrids on the Pacific coast through ecological niche analyses. The results indicate that the hybrid crocodiles and the parent species share preferences in at least three climatic variables: average temperature range, isothermality, and minimum temperature of the coldest month. Furthermore, it was found that the climatic niche of the hybrids is more similar to that of the C. moreletii leaving reminiscent areas for C. moreletii in Nuevo León, San Luis Potosí and small areas far from the coast in Veracruz, coinciding with what was previously reported by molecular analysis. On the other hand, the climatic niche of the hybrid crocodiles is also sufficiently similar to that of C. acutus, having the possibility to colonise the Pacific coast extensively, leaving reminiscent small areas for C. acutus on the northern coast of Sinaloa, southern of Sonora, central coast of Oaxaca and small inland areas of the Pacific coast.

Keywords: Crocodilians, ecological niche, hybrids, species model distributions, conservation, Mexico

pdf 02.Factors contributing to the biodiversity value of an archaeological landscape in Jordan


Subscription / purchase required

pp. 102-108


Authors: Omar Attum, Sufian Malkawi, Nashat Hamidan


Abstract: Archeological landscapes are important places because they protect areas of historical importance, shape cultural and national identity, are recreational spaces, and vital sources of tourism revenue. Archaeological landscapes have the potential to assist in reptile conservation. The objective of this study was to compare the diurnal reptile richness of an archaeological site to the reptile richness of a nature reserve (treatment control for biodiversity value) and a modern olive grove (treatment control for poor biodiversity value). Our results suggest that archaeological landscapes provide valuable reptile habitat, as our archaeological site supported similar reptile richness as the natural site, with both sites having higher species richness than the modern olive tree farm. The high reptile richness and densities were the result of high potential food availability and habitat mosaic of relatively low tree density and open areas with exposed, tall, rocky ruins. Reptile richness had a negative relationship with tree density. The ruins and high food availability of the archaeological site supported higher densities of saxaphilic lizard species as the density of these species increased as mean maximum rock height and percentage of green ground vegetation cover increased. Promoting the reptile richness of archaeological sites provides another justification for the protection and visitor appreciation for archaeological sites as places of historical, cultural and biodiversity importance.

Keywords: Stellagama stellio, Ptyodactylus puiseuxi, reptile richness, rock outcroppings, vegetation greenness indices


pdf 03.Egg retention in wild-caught Python bivittatus in the Greater Everglades Ecosystem, Florida, USA


Open Access

pp. 109-113


Authors: Gretchen E. Anderson, Frank N. Ridgley, Jillian M. Josimovich, Robert N. Reed, Bryan G. Falk, Amy A. Yackel Adams & Andrea F. Currylow


Abstract: Retention of eggs in oviducts beyond the normal oviposition period is a common problem for captive reptiles, but the occurrence of egg retention in wild populations is largely unknown. The Burmese python (Python [molurus] bivittatus; Kühl 1820) is an oviparous snake native to south-eastern Asia that is now established in southern Florida. From 2011–2019, invasive Burmese pythons were opportunistically removed from Everglades National Park and Big Cypress National Preserve, humanely euthanised, and necropsied to determine reproductive condition. A total of 258 females of reproductive size were found to exhibit various stages of oviposition which generally aligned with purported annual reproductive timing. However, we encountered five pythons during the post-ovulatory period (Aug–Feb) showing signs of recent oviposition with retained eggs. Most of these cases comprised a small number of retained eggs, likely representing some portion of the total clutch. Because this condition is nearly absent in wild animal literature, our observations suggest retained eggs in wild snakes may be more common than previously assumed, possibly slowing or otherwise impacting population growth. However, we recognise that for an invasive species like the Burmese python in Florida, the egg retention rate may be higher in the non-native range compared to the native range due to maladaptation to novel habitats or environmental conditions. Additional research is needed to determine the exact causes of egg retention and investigate the implications for population dynamics on this and other snake species.


Keywords: invasive species, dystocia, snakes, Burmese, reproduction


pdf 04.A revised system for interpreting great crested newt habitat suitability indices


Open Access

pp. 114-119

Authors: Andrew S. Buxton & Richard A. Griffiths

Abstract: A widely used system for assessing habitat for the great crested newt uses five categories ranging from ‘poor’ to ‘excellent’ based on thresholds for the Habitat Suitability Index (HSI). However, how these categories relate to pond occupancy, at an England-wide scale, is unknown. Equally, the Habitat Suitability Index system has so far only been validated using traditional direct observation methods rather than environmental DNA protocols that are becoming commonplace. Without further validation on a national scale, misleading decisions may be made concerning the likely presence or likely absence of great crested newts. Using environmental DNA data collected from over 5300 ponds distributed across much of England, we show that the existing scoring system underestimates pond occupancy in the lower categories and overestimates pond occupancy in the higher categories, while the median habitat suitability index value was found just within the 'good' category. We found that the median habitat suitability index for occupied ponds was 0.7, confirming this value as a target to aim for when creating or restoring ponds for great crested newts. We suggest a revised system based on the median occupied pond HSI score, whereby the two extreme 'poor' and 'excellent' categories each contain just 10 % of occupied ponds; the 'below average' and 'good' categories each contain 20 % of all occupied ponds, and the 'average' category contains the central 40 % of occupied ponds. Although regional variation in estimated pond occupancy rates using this system may need to be accounted for when interpreting HSI scores, the revised scoring system is generally robust across England. Both the existing and revised HSI scoring systems are no substitute for surveys, and caution is needed when interpreting absence of newts based on habitat suitability data only.

Keywords: Habitat Suitability Index, Triturus cristatus, HSI, UK regions, environmental DNA

pdf 06.Temporal partitioning of hatching, maturation, and surface activity by reptiles in Florida longleaf pine-wiregrass sandhills

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Subscription / purchase required

pp. 130-141


Authors: Sky T. Button, Cathryn H. Greenberg & James D. Austin


Abstract: Temporal partitioning of life history traits among syntopic reptiles can facilitate co-occurrence, but may be influenced by environmental factors and evolutionary history. We used 24 years of continuous capture data in the Florida sandhills to evaluate the timing and duration of hatching, maturation and/or surface activity for ten reptile species, spanning multiple clutch strategies, taxonomic relationships, and habits. We hypothesised: i) species would differ in seasonal timing of hatching and maturation; ii) hatching and maturation periods would be more seasonally-synchronised in fossorial than terrestrial or semi-aquatic reptiles; iii) monthly and annual temperature anomalies would be positively related to hatching, maturation, and surface activity anomalies, and iv) groupings of reptiles by clutch strategy, taxonomic relationship, and habit, would explain more variation in the timing and duration of hatching and maturation than species alone. Seasonal timing of response variables varied widely among species. Hatching peaked for > 1 species during most calendar months. Maturation and surface activity periods ranged from aseasonal to highly-seasonal among species. Hatching began 1.5 months earlier and was more prolonged for terrestrial than fossorial species overall. Hatching peaked in early to mid-summer for terrestrial and fossorial species, and winter for the semi-aquatic Kinosternon subrubrum. Terrestrial and fossorial species did not differ in average timing, duration, or overlap of maturation periods; semi-aquatic Liodytes pygaea matured more consistently across all seasons than other species. Monthly temperature anomalies were negatively correlated with monthly maturation for Plestiodon egregius. Annual temperature and precipitation anomalies were related to annual hatching, maturation, and surface activity trends for several species. Taxonomic relationship, habit, and species explained some variation in hatching and maturation timing and duration. Our results illustrate the influence of environment and evolutionary relationships on the timing of important life history traits. 


Keywords: Age class, Drift fence, Community, Interspecific, Life history


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Please note that as from Volume 31 Number 1 (January 2021) on, the Herpetological Journal will be available as an online publication only - the last print edition will be Volume 30 Number 4.   

Aligning with this change, it is now no longer possible to purchase a subscription that includes a print copy of the HJ.  All members who have existing HJ print subscriptions that remain active as at end June 2020 will receive the full four 2020 print editions.  New subscribers or renewals after this time will only have option to subscribe to the online only subscription package.  Subscription pricing has been amended to reflect the content changes.