Schlange

Herpetology

Research


Our research activities focus on the Neotropical herpetofauna (Central and South America, Mexico, and the West Indies).

Formerly, we carried out additional research activities in Malawi.

The basis of our research is usually a species inventory of the given region with a taxonomic treatment of its faunal elements. Then, based on external morphological traits, genital morphological data, and molecular genetic markers, we evaluate the phylogenetic relationships of the species in question and establish hypotheses for the evolution of the studied taxa. Statistical analyses of the zoogeography of the species assembledges are also part of our work.

Since 1995, the genus Anolis is the animal group we have studied most intensively. More than one third of the 96 species of Anolis currently known to occur in Central America have been described or resurrected by us. With close to 400 recognized species, the genus Anolis provides great opportunities to study various aspects of speciation.

Diversity, taxonomy, and phylogeny of the herpetofauna of Latin America

Since 1995 we have conducted herpetological research in all Central American countries, as well as in selected South American countries. Projects on the Antilles are in preparation. We plan to do fieldwork on Hispaniola in October and November of this year. Thus, we have established excellent contacts and some long-term colaborations with scientists, universities, museums, and ministries in Latin America. The Senckenberg herpetological laboratory in Frankfurt, Germany, is the only lab in the world that is undertaking projects on the diversity, taxonomy, and phylogeny of the herpetofauna throughout Central America (Mexico, Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, and Panama). This makes possible large-scale comparisons and, in some cases, this can highlight problems that would otherwise not be visible or obvious, e.g., the study of the geographic variation of a “species” that is subsequently understood to represent actually a complex of species. Also for the evaluation of supra-regional phenomena such as population dynamics in anurans, this holistic perspective is helpful because it makes it easier to detect patterns.

For the past several years, the focus of our herpetological research in South America has been in Bolivia, Paraguay, Peru, and Ecuador. In Bolivia, Senckenberg has established a Research Station (Ecological Research Station Chiquitos, San Sebastian) providing an infrastructure that has allowed the completion of two doctoral dissertations and several undergraduate research projects. In Costa Rica, we are the leading partners in a long-term herpetology monitoring project.

Aside from numerous publications in international journals, the results of our work in Latin America has resulted in the publication of several books on the diversity, taxonomy, and identification of the Central American herpetofauna, as well as several regional identification guides. Two of the more prominent works are the following comprehensive monographs on the herpetofauna of Central America:

Köhler, G. (2008): Reptiles of Central America. 2nd edition. Offenbach (Herpeton), 400 pp.
Köhler, G. (2011): Amphibians of Central America. Offenbach (Herpeton), 379 pp.

 

Diversity, taxonomy, and phylogeny of anoles (genus Anolis)

The anoles (Anolis sensu lato), with close to 400 recognized species, represents the most diverse lizard genus, with more species being described almost every year. The phylogenetic relationships and taxonomy of this group of lizards remain subject to serious controversy in the recent literature. Indeed, our understanding of the systematics of these lizards is still at a low level. For most “species groups” of anoles, as proposed by various researchers in the literature, the evidence that these actually represent monophyletic groups is meager. Some of them probably are natural groups of species, while others represent artificial groupings of species that are simply similar and are placed together because of particular character resemblances.

Based on morphological characteristics, such as pholidosis, body proportions, osteology, and hemipenial morphology, the Central American anoles are being revised. In addition to fieldwork in the natural habitat, the extensive collections in European, North American, and Central American museums are being integrated into this study.

Hemipenial morphology as a source of information for systematics and taxonomy in anoles had received relatively little attention in the past. A comparative study of shape and surface ornamentation of the male copulatory organs indicates an enormous diversity in these lizards. Intraspecific and geographic variation is negligible, whereas there is substantial variation among species. We have documented 12 species pairs of Central American anoles that are extremely similar in their external morphology (scalation and morphometrics), but differ drastically in their hemipenial morphology. Typically, one of the species in each pair has a large bilobed hemipenis whereas the other has a small unilobed organ. Thus, these are cryptic species that were differentiated based on their divergent hemipenial morphology. In all cases studied, we found a close correlation between female cloacal morphology and male hemipenial morphology.

We can assume that differentiation took place in isolation (allopatry) with males and females coevolving. The available molecular data indicate a close relationship of the differing hemipenial morphs. This situation suggests that changes in genital morphology evolve very quickly in Anolis, probably by a self enhancing process like “runaway evolution by cryptic female choice” or “chase away evolution by sexual conflict.”

Along contact zones between closely related species, individuals with intermediate hemipenal morphologies are found, indicating that hybridization occurs. This is confirmed by looking at hemipenial morphology of hybrids produced in the laboratory. This phenomenon raises the question of functional neutrality for anole genital morphology. Female cloacal morphology closely matches the hemipenial morphology of sympatric males. Thus, hemipenial morphology is probably not functionally neutral. However, there is no evidence of reinforcement along contact zones of closely related anole species. Differences in hemipenal morphology does not prevent hybridization, indicating that a “key-lock” mechanism is not operating in anoles.

Genital morphology in anoles is an understudied yet promising area of research. There are many potential projects for investigating the role that genital morphology plays in speciation in the genus Anolis, including the mating systems in anoles, processes during copulation, sperm storage, and the effects of genital morphology on sperm storage.

Publications

Taxonomic studies of selected genera of the family Gymnophthalmidae

The family Gymnophthalmidae is sometimes collectively called the microteiids because this assemblage of several hundred, mostly small bodied species was historically recognized as a subfamily of the Teiidae. Based on morphological characteristics (pholidosis, body proportions, and hemipenial morphology), selected genera of this family are being revised. We aim to clarify existing taxonomic issues, provide a synopsis of the morphological variation of the species studied, an identification key to the genera (restricted to a certain country if useful), and dot distribution maps. Aside from fresh collections obtained during our own fieldwork, we aim to include in our revisionary work as many specimens as possible from existing collections worldwide.

So far, the results of the revisions of the genera Alopoglossus, Echinosaura, Euspondylus, and Proctoporus have been published, including the descriptions of a new species of Echinosaura, three new species of Euspondylus, and two new species of Proctoporus.

Research and conservation project Utila Iguana

The Utila Iguana (Ctenosaura bakeri) is a large iguanid lizard that is restricted to the small Caribbean island of Utila (Islas de la Bahia, Honduras) and threatened by extinction due to overhunting and loss of habitat. The “Research and Conservation Project Utila Iguana” was established in 1994 as a joint project by the Frankfurt Zoological Society and the Senckenberg Nature Research Society. As originally planned, in 2008, the responsibility and leadership of the project was transferred to the Bay Islands Foundation.

The goal of the project is the long-term conservation of Ctenosaura bakeri in its natural environment on Utila. The primary activities of the project are to develop a broad education and information program for the local community, investigate the natural history and reproductive ecology of C. bakeri, establish and maintain a headstart program, and protect iguana habitat on Utila.

For volunteers, the “Conservation Project Utila Iguana” offers a multitude of tasks and activities at the “IGUANA Research & Breeding Station” on Utila, including environmental education, public relations, animal care, gardening, station maintenance, and ecological research, to name a few examples.

http://www.utila-iguana.de/

Research Activities worldwide

Malawi

A herpetological biodiversity analysis as conservation tool for sustainable land use in Malawi

Participating institutes and organizations (aside from the Research Institute and Nature Museum Senckenberg):

Department of Ecology and Evolution, Siesmayerstrasse, Johann Wolfgang Goethe University D-60054, Frankfurt am Main, Germany; Cultural and Museum Centre Karonga (CMCK), Private Bag 16, Karonga, Malawi (link: www.palaeo.net/cmck/).

Malawi is an elongated country, bordered by Tanzania in the north, Zambia in the west, and Mozambique in the east and south. The total territorial area is about 120.000 square km of which circa 20% is covered by Lake Malawi. In fact, Malawi contains some of the world’s most important wetland ecosystems including shoreline plains of Lakes Malawi, Chiuta, and Chilwa, a diversity of Miombo ecosystems, and marshes of the Shire river system. The climate is sub-tropical with a rainy season from November to May. Despite the relative small extension of the country this variety of habitat makes Malawi rich in biodiversity. The nearly 1.500 vertebrate species known are actually divided as follows: 163 mammals, 80 amphibians and 140 reptiles, 548 fish and 620 birds.

The status of the knowledge of amphibians and reptiles of Malawi is still rudimentary. The most available data about distribution of those animals are poor and above all outdated. The alteration of landscape through human activities, taken place mainly in the last decades, makes it sure that this knowledge does no longer reflect the actual situation of natural communities.

Today, the continuous increase of cultivable areas correlated to deforestation and habitat fragmentation places the natural populations to serious hazard. Without new and up-to-date information it is impossible both to value the importance of the biodiversity erosion and to establish effective conservation programs.

Through the acquisition of new data about the diversity of amphibians and reptiles in different farming systems as well as in degraded forest will be possible to estimate the influences of the different land use on herpetological communities.

During the last twenty years it has also become obvious that conservation of nature and biodiversity is only possible if local people are involved and able to obtain economic benefit. The project sets out to prove the essential importance to merge biodiversity conservation efforts with local economic development, especially with sustainable agricultural practices.

In this perspective amphibians and reptiles are used as model groups to test biodiversity of differently used landscapes. Particularly the amphibians are very sensitive to environmental changes, due to their dependence both of terrestrial and aquatic ecosystems.

 

Publications

Channing, A., Hillers, A., Lötters, S., Rödel M.-O, Schick, S., Conradie, W., Rödder, D., Mercurio, V., Wagner, P., Dehling, J.M., Du Preeez, L.H., Kielgast, J. & Burger, M. Taxonomy of the super-cryptic Hyperolius nasutus group of long reed frogs of Africa (Anura: Hyperoliidae), with descriptions of six new species. Zootaxa, 3620(3): 301-350.

Mercurio V. 2011. Amphibians of Malawi, an analysis of their richness and community diversity in a changing landscape; Chimaira Verlag, Frankfurt am Main, Germany, pp. 393.

Mercurio, V. 2009. Reproductive diversity of Malawians anurans; Herpetology Notes, 2: 175 –183.

Mercurio, V. 2009. Advertisement calls of three species of Arthroleptis (Anura: Arthroleptidae) from Malawi; Journal of Herpetology, 43(2): 345–350.

Mercurio V., 2007. Polemon christyi and Elapsoidea boulengeri: two new snakes distribution records for Malawi; Salamandra, 43(4): 253-255.

Mexico

Recently, several nominal species of Mexican anoles have been placed into the synonymy of other species (see publications: Köhler 2011, 2012): The examination of the holotype of Anolis baccatus Bocourt 1873 revealed that it is a representative of A. carolinensis Voigt 1832 and, therefore, this name was synonymized with the latter epithet. Furthermore, the nominal species A. cumingii Peters 1863 and A. guentherii Bocourt 1873 were synonymized with A. sericeus Hallowell 1856 and A. grahami Gray 1845, respectively.

The Pacific versant of southern Mexico (states of Oaxaca and Guerrero) is home to a distinct assembledge of anoles (genus Anolis). The majority of species found in this region shares the presence of an oval patch of usually three greatly enlarged supraocular scales (all Mexican Pacific species except for A. macrinii and A. unilobatus). The currently recognized species known to occur along the Pacific versant of southern Mexico can roughly be divided into species with moderately to strongly keeled midventral scales (i.e., A. forbesi, A. isthmicus, A. megapholidotus, A. microlepidotus, A. nebuloides, A. nebulosus, A. quercorum, A. subocularis, and A. unilobatus) and those with usually perfectly smooth (faintly to weakly keeled in some individuals of A. macrinii) midventral scales (i.e., A. dunni, A. gadovii, A. liogaster, A. macrinii, A. omiltemanus, and A. taylori).

During recent field work (October/November 2012 and February/March 2013) we have surveyed the species of anoles occurring in the states of Oaxaca and Guerrero. We collected representatives of all currently recognized species including material from near the respective type localities. Also, we discovered an undescribed species of anole that appears to be an arboreal pine forest specialist in the southern Sierra Madre del Sur.

Belize

In October 2005, we did some field work in Belize to study the Anolis species occuring in that country. A focus of our study was the geographic variation of the species in the Anolis sericeus complex, because the species identity of the Belize populations of this group remained uncertain. Based on its hemipenial morphology (a large bilobed organ), we were able to positively assign the populations in Belize to the species A. sericeus (see: Köhler & Vesely 2010: A revision of the Anolis sericeus complex with the resurrection of A. wellbornae and the description of a new species (Squamata: Polychrotidae). Herpetologica 66 (2): 207-228). Other common species of anoles in Belize are A. lemurinus, A. rodriguezii, A. sagrei, and A. uniformis.

 

Guatemala

The Anoles (Genus Norops) of Guatemala

This is a study of the morphological variation and taxonomy of the genus Norops in Guatemala. The results are published as a series of papers, the species grouped according to zoogeographic regions: 1. Pacific versant; 2. Caribbean versant; 3. Highlands.

Seven species of anoles are known to occur along the Pacific versant of Guatemala below 1500 m elevation (N. cristifer, N. dollfusianus, N. laeviventris, N. macrophallus, N. petersii, Norops sericeus complex Pacific versant” and N. serranoi).

In Guatemala, Norops cristifer is known only from a few specimens from the southwestern portion of the country. This species can be distinguished from the other Pacific versant anoles by its very short hind legs and a usually distinct dorsal crest. Norops dollfusianus inhabits the foothills of the mountains along the Pacific versant (400-1700 m above sea level) and can be distinguished from the other Pacific versant anoles by the presence of an undivided prenasal scale and a yellow dewlap in adult males. Norops macrophallus inhabits the lowland and the foothills of the mountains along the Pacific versant (near sea level to 1200 m elevation) and can be differentiated from the other Pacific versant anoles by the following combination of characters: long hindlimbs, a divided prenasal scale, 19-25 subdigital lamellae on 4th toe, and a flesh-colored dewlap in adult males. Norops serranoi inhabits the lowland and the foothills of the mountains along the Pacific versant (near sea level to 1040 m elevation) and can be differentiated from the other Pacific versant anoles by the following combination of characters: long hindlimbs, a divided prenasal scale, 25-33 subdigital lamellae on 4th toe, and a red dewlap in adult males. “Norops sericeus complex Pacific versant” is widely distributed along the Pacific versant of Guatemala (near sea level to 1040 m elevation) and can be differentiated from the other Pacific versant anoles by the following combination of characters: short hindlimbs, a conspicuously enlarged superciliary scale, an extremely small external ear opening, no enlarged postanal scales, and dewlap of adult males yellowish-orange with a central blue blotch. Usually several (up to four) of these species occur sympatrically.

Honduras

Biodiversity and taxonomy of the herpetofauna of Honduras

With a surface area of 112,088 km2, Honduras is the second largest country of the Central American land bridge. According to the most recent species list of the Honduran herpetofauna (McCranie 2009), there are 129 amphibian and 244 reptile species recorded for the country. This breath-taking diversity is due to the rich structuring of the country that makes Honduras a mosaic of rain forests, pine forests, wet forests, dry forests, cactus vegetation, savannahs, swamps and mangroves. Often only a few kilometers are traversed crossing from one extreme environment (with respect to climate, flora and fauna) into another.
For an explorer, such contrasts are exciting, as is the knowledge that large areas of the country are still virtually unknown to science. The research deficit is also apparent in the large number of amphibians and reptiles discovered in Honduras in the past 20 years. Between 1995 and 2002, the herpetofauna of Honduras was one of the main research areas of the Senckenberg Herpetology Department. During this period we have undertaken one or two expeditions to Honduras per year resulting in the discovery of many undescribed species.

El Salvador

Biodiversity and taxonomy of the herpetofauna of El Salvador

The herpetofauna of El Salvador, the smallest country in Central America, is still poorly known. Since the first comprehensive treatment of the herpetofauna of El Salvador by Robert Mertens (1952: Abh. senckenb. naturf. Ges. 487) only a few herpetological publications have addressed the amphibians and reptiles of this country; (see overview in Köhler (1996: Senckenbergiana Biologica 76: 29-38). The activities of Senckenberg’s researchers in El Salvador in the 1950s have resulted in a large collection of El Salvadorian amphibians and reptiles housed in the Senckenberg Research Institute.
During several recent expeditions to El Salvador (1997 and 1998), research on the diversity and taxonomy of the El Salvadorian herpetofauna has continued. Aside from several articles in journals a monographic treatment of the herpetofauna of El Salvador has been published in 2006.

Nicaragua

Biodiversity and taxonomy of the herpetofauna of Nicaragua

Nicaragua is the largest country in Central America. Compared to its neighboring countries Costa Rica and Honduras, it has a less rich physiography resulting in a much poorer diversity of its herpetofauna. During a series of expeditions to Nicaragua (1996-2008) several new species were discovered and other species have been reported for the first time in that country. In 1999, a treatment of the herpetofauna of Nicaragua was published providing keys for the identification of the orders, genera and species of Nicaraguan amphibians and reptiles. On 12 October 2001, Köhler’s book „Anfibios y Reptiles de Nicaragua“ was presented to the public at the Ministerio del Ambiente y los Recursos Naturales (Marena), Managua; the Ministry of Environment, high-ranking Marena officers, the German Ambassador as well as KfW and GTZ representatives were present at this event. The publication of this book was funded by the World Bank project “Corredor Biologico Atlantico”. In the course of his doctoral work (completed 2009), Javier Sunyer has worked intensively on various aspects of the Nicaraguan herpetofauna and has produced a large collection of amphibians and reptils from this country.

Costa Rica

Biodiversity Monitoring

In many areas of Central America ecological systems are increasingly destroyed by unsustainable land use and by false economic conditions. The negative aspects of these land use practices on ecosystems and their biodiversity are often ignored or simply unknown. Furthermore the pressure on natural ecosystems is rising steadily through regional poverty, lack of education of the local population, and the widespread effects of global climate change.

Agricultural activities always have an impact on local biodiversity, but they don’t necessarily have to be in contrast to supporting biodiversity. Plantations – and in this context not just reforestation projects are meant – may well increase the local diversity of organisms. To measure the influence of agricultural activities and also the success of projects aiming at the linking of habitat fragments on local and regional biodiversity, continuous and standardized surveys – monitoring projects – are needed.

Panama

Biodiversity, Ecology, and Zoogeography of the Herpetofauna inhabiting the Cordilleras of Western Panama

Institutions and organizations involved (apart from Senckenberg Research Institute):

  • Department of Ecology and Evolution, Johann Wolfgang Goethe-University, Siesmayerstraße 70-72, 60323 Frankfurt am Main, Germany
  • Universidad Autónoma de Chiriquí (UNACHI), Davíd, Chiriquí, Panama

Panama is situated within the geologically youngest part of Central America. Approximately twelve million years ago, several islands, driven by tectonic movements, entered the gap between South America and Central America, called the Panamanian Portal. About three million years ago, the present land bridge of Lower Central America was finally established. Since then, animals and plants have dispersed via this connection in both directions, resulting in today’s presence of North, South, and Central American-originated biota in this region. Nowadays, Panama is part of the Mesoamerican biodiversity hotspot.

Unlike its neighboring country of Costa Rica, Panama’s biodiversity remains scarcely explored. This applies especially to the remote mountainous regions in the western part of the country, whose slopes rise to almost 3500 m a.s.l. and still support vast, intact stretches of cloud forest. A perspicuous indication of the extremely high species richness of these highlands – simultaneously revealing the extent of our ignorance thereof – is the discovery of four new species of lizards within a 24-hour period during a Senckenberg expedition in 2006.

In the context of their respective dissertation projects initiated in autumn 2007, Andreas Hertz (amphibians) and Sebastian Lotzkat (reptiles) investigate the herpetofauna along a transect approximately 250 km long and 30 km wide (the green area in the map above) that comprises the western Central Range at elevations from about 1000 m a.s.l. upwards. Questions regarding taxonomy, systematics, and biogeography are the main focus, necessitating a preferably complete species inventory as a primary result. Several descriptions of species formerly unknown to science are to be expected, as well as first records of known species for Panama. On this foundation, taxonomic and zoogeographic analyses based on morphology, anatomy, and molecular genetics will be conducted, providing new findings regarding relationships, distribution, ecology, evolution, and conservation of the encountered populations. The calculation of diversity indices allows for the identification of so-called biodiversity hotspots, which should be given priority in the course of future conservation efforts.

In the face of the present extinctions, which seem to be primarily driven by human impact, such fundamental measures of biodiversity research are critically important. This applies particularly to the amphibians, which are exceptionally exposed to various environmental influences. For them, anthropogenic habitat destruction – although being the gravest – is by far not the only serious threat. Their highly permeable integument is not much of a barrier against environmental toxins. Thus, their generally aquatic larvae are at the mercy of water pollutants, while the adults suffer from air pollution and climatic changes. These traits allows amphibians to be excellent bioindicators. Furthermore, the EIDs (Emerging Infection Diseases) specific to amphibians have manifested themselves during the past 30 years. Since the 1980s, substantial decreases as well as total losses of frog species have been documented in the highlands of southern Central America. These declines, affecting even those populations inhabiting protected areas with primary vegetation, are most commonly attributed to the chytrid fungus Batrachochytrium dendrobatidis. In the context of this study, various populations of severely declined or supposedly extinct species could be discovered in the Cordillera Central of western Panama (see press release in German), and samples from selected populations have been tested for the presence of the fungus with different results.

The first fieldwork period in the context of this project took place between May and August 2008. During this time, Andreas Hertz, Sebastian Lotzkat, and the undergraduate students Leonhard Stadler and Nadim Hamad, under the initial direction of Dr. Gunther Köhler and subsequent occasional accompaniment of the Panamanian biologist Arcadio Carrizo, visited selected localities within the western highlands. During 2009, two more research trips to Panama, each of two and a half months, were conducted. Again two undergraduate students, Joe-Felix Bienentreu and Frank Hauenschild, added to the team. Several expeditions were enriched by the participation of the Panamanian counterparts Rosalba De Leon, Abel Batista, Arcadio Carrizo, Marcos Ponce and Juan Castillo. The hitherto last research travel to Panama took place between May and August 2010.

These four research trips to Panama have yielded a collection of approximately 80 amphibian and 114 reptile species. Preliminary analyses of these collections have already produced some very interesting findings. Among these are new species, like the tiny salamander Bolitoglossa jugivagans that is known from a single individual, or the snail-eater Sibon noalamina (see press release) that has recently been declared one of the “Top 10 New Species 2012”. Moreover, several species known from neighboring Costa Rica could for the first time be documented to occur in Panama. In view of several specimens with still unsolved specific identities, further interesting results may be expected from exhaustive examination of the material.