Research

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.

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.

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.

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 , 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.

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.

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.

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.

Amphibians and reptiles are ideal target species for such monitoring studies in Central America. On the one hand they represent the dominant groups of vertebrates and on the other hand they are easily detectable. We have designed a simple but efficient monitoring system for ground-dwelling amphibians and reptiles which can be established quickly and with relatively low costs. The basic principle of this monitoring system is a network of pitfall traps which are connected through a system of zinc metal drift fences. The use of other materials for the drift fences in earlier times – like plastic foil – proved not to be useful because rain, wind and overgrowing plants always destroyed the fences within short time. The usage of zinc metal ensures the monitoring system to stay in a good condition. Size and composition of the pitfall traps makes possible the monitoring of ground-dwelling anurans, lizards, and small to medium sized snakes (up to 100 cm total length). In addition to the animal data we are collecting climate data such as temperature and rainfall on site by using data logger. Our monitoring approach is a non-invasive method. The animals are caught in the pitfall traps just for some hours and are released back into nature immediately after recording, marking and photographing.

We follow the approach of participatory monitoring, i.e. including the local people. Local employees are being trained as parataxonoms. Trapped animals are recorded on a daily basis by our local co-workers. Therefore, this monitoring is done year-round and we obtain continuously data on the activities and population dynamics of the local herpetofauna. The recent experiences are very encouraging: our local staff is proud to be involved into scientific studies and is performing their tasks conscientiously. The active involvement of locals in this monitoring project also represents a kind of environmental education. Furthermore, this opens up new prospects and working options for the local people.

The collected data allows assessments of the local biodiversity, and their development in correlation with agricultural activities. It can also yield information on population trends and migration patterns of individual species. Our aim is to establish and develop these monitoring projects at different locations across Central America to generate a database that will allow subsequent regional analyses of biodiversity patterns (keyword: Biological Corridor Mesoamerica). Molecular genetic analysis will also provide information on the influence of habitat fragmentation and habitat networks on the genetic diversity within populations and metapopulations. The results of our studies will also yield recommendations in which way the ecological regeneration and local biodiversity can be increased while maintaining high agricultural standards.

With support by Globetrotter Ausrüstung GmbH (www.globetrotter.de) and Bauminvest (www.bauminvest.de) we have established a longterm monitoring project for amphibians and reptiles at a reforestation finca in Costa Rica (near the village San Rafael, Provinz Alajuela; 84°29’22’’N, 10°43’39’’W, 60 m NN).

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 , 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  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.

2017

Guedes, T. B., Sawaya, R. J., Zizka, A., Bérnil, R. S., Jansen M., Passos P., Prudente A. L. C., Cisneros-Heredia, D. F., Braz, H., Nogueira, C. d. C. & Antonelli, A. (2017): Patterns, biases, and prospects in the distribution and diversity of Neotropical snakes. Global Ecol Biogeogr. 2017; 27:14–27. https://doi.org/10.1111/geb.12679

Köhler, J., Jansen, M., Rodríguez, A., Kok, P. J. R.,  Toledo, L. F., Emmrich, M., Glaw, F., Haddad, C. F. B., Rödel, M.-O., & M. Vences (2017): The use of bioacoustics in anuran taxonomy: theory, terminology, methods and recommendations for best practice. Zootaxa, 4251, 1-124, 2017

 Caminer, M.A., Milá, B. Jansen, M., Fouquet, A., Venegas, P.J., Chávez, G., Chek, A. & S. R. Ron (2017): Systematics of the Dendropsophus leucophyllatus species complex (Anura: Hylidae): Cryptic diversity and the description of two new species. PLOS ONE | DOI:10.1371/journal.pone.0171785 March 1, 2017

2016

Jansen, M., A. Masurowa & R. B. O’Hara (2016): Temporal variation, duty cycle and absolute calling effort during sustained calling of Leptodactylus mystacinus (Anura: Leptodactylidae). Salamandra 52(4): 328-336.

 Pansonato, A., A. C. Veiga-Menoncello, J. R. Mudrek, M. Jansen, S. M. Reco-Pimentel, I. A. Martins & C. Strüssmann (2016): Two new species of Pseudopaludicola Miranda-Ribeiro, 1926 (Anura: Leptodactylidae: Leiuperinae) from eastern Bolivia and western Brazil. Herpetologica, 72(3): 235-255.

Jansen, M., M. Plath, F. Brusquetti & M. Ryan (2016): Asymmetric frequency shift in advertisement calls of sympatric frogs. Amphibian-Reptilia, 37: 137-152

2015

Schulze, A., Jansen, M. & G. Köhler (2015): Tadpole diversity of Bolivia`s lowland anuran communities: molecular identification, morphological characterization, and ecological assignment. Zootaxa, 4016(1):1-111.

2014

Gehara, M.,  Crawford, A. J., Orrico, V. G. D., Rodríguez, A., Lötters, S., Fouquet, A., Barrientos, L. S., Brusquetti, F., De la Riva, I., Ernst, R., Urrutia, G. G., Glaw, F.,  Guayasamin, J. M., Hölting, M., Jansen, M., Kok, P. J. R., Kwet, A., Lingnau, R., Lyra, M., Moravec, J., Pombal Jr., J. P., Rojas-Runjaic, F. J. M.,  Schulze, A., Celsa Señaris, J., Solé, M., Rodrigues, M. T., Twomey, E., Haddad, C. F. B., Vences, M. and Köhler J. (2014 ). High levels of diversity uncovered in a widespread nominal taxon: continental phylogeography of the Neotropical tree frog Dendropsophus minutus. 2014. Plos One, 10 September 2014.

Brusquetti, F., Jansen, M., C. Barrio-Amorós, Magno Segalla & C. F. B. Haddad (2014): Taxonomic review of Scinax fuscomarginatus (Lutz, 1925) and related species (Anura; Hylidae). Zoological Journal of the Linnean Society, 171, 4: 783-821

2012

Jansen, M. & Schulze: Molecular, morphology and bioacoustic data suggest Bolivian distribution of a large species of the Leptodactylus pentadactylus group (Amphibia: Anura: Leptodactylidae). Zootaxa 3307: 35-47.

Schulze, A. & M. Jansen: One species, two strategies? Oviposition site variation in a member of the Leptodactylus pentadctylus group (Amphibia: Anura: Leptodactylidae) Studies on Neotropical Fauna and Environment, DOI:10.1080/01650521.2012.711102

2011

Jansen, M. R. Bloch, A. Schulze & M. Pfenninger: Integrative inventory of Bolivia’s lowland frogs reveals hidden diversity. Zoologica Scripta 40(6): 567-583.

2010

Schulze, A. & M. Jansen: A tadpole of Trachycephalus venulosus (Anura: Hylidae) as prey for a fishing spider (Araneae: Pisauridae) in the Bolivian Chiquitano Dry Forest. Herpetology Notes 3: 297-298.

Jansen, M. & G. Köhler: Reptilia, Squamata, Amphisbaenidae, Amphisbaena cegei Montero, 1997, and Reptilia, Squamata, Teidae, Tupinambis rufescens (Günther, 1871): vertical range extension. CheckList 6(4): 503-504.

Mebs, D., M. Jansen, G. Köhler, W. Pogoda & G. Kauert: Myrmecophagy and alkaloid sequestration in amphibians: A study on Dendrobatidae (Ameerega picta) and Microhylidae (Elachistocleis sp.) frogs. Salamandra 46(1): 11-15.

2009

Jansen, M., A. Schulze, L. Werding & B. Streit: Effects of extreme drought in the dry season on an anuran community in the Bolivian Chiquitano region. Salamandra 45(4): 233-238.

Jansen, M., L. Gonzales & G. Köhler: Description of a new species of Xenopholis (Serpentes: Colubridae) from the Cerrado of Bolivia with comments on Xenopholis scalaris in Bolivia. Zootaxa 2222: 31-45.

Jansen, M.: Measuring temporal variation in calling intensity of a frog chorus with a  data logging sound level meter: A case study in Bolivia. Herpetology Notes 2: 143-149.

Schulze, A., Jansen, M. & G. Köhler: Diversity and ecology of an anuran community in San Sebastián, Bolivia. Salamandra 45(2):75-90.

2008

Jansen, M.: New and noteworthy records of snakes from Bolivia. Herpetological Review 39(3): 374-375.

Jansen, M & G. Köhler: A new species of Phalotris (Reptilia, Squamata, Colubridae) from the eastern lowlands of Bolivia. Senckenbergiana biologica 88: 103-110.

Jansen, M & J. Köhler: Intraspecific combat behavior of Phyllomedusa boliviana (Anura: Hylidae) and the possible origin of visual signaling in nocturnal treefrogs. Herpetological Review 39(3): 290-293.

2007

Jansen, M., L. Gonzales & G. Köhler: New species of Hydrolaetare (Anura: Leptodactylidae) from Bolivia with some notes on its natural history. Journal of Herpetology 41(4): 724-732.

Jansen, M & J. Köhler: Description of the advertisement call of Eleutherodactylus fraudator. South American Journal of Herpetology 2(3): 198-200.

Cacciali, P. & Köhler, G. (2014): Notes on daily activity patterns in Teius teyou (Squamata: Teiidae) in the dry Chaco. The Herpetological Bulletin 129: 24-25.

Cacciali, P. Morando, M, Köhler, G. & Avila, L. (2016): On the distribution of the genus Teius Merrem, 1820 (Reptilia: Squamata: Teiidae). Zootaxa 4136 (3): 491–514.

Cacciali, P., Cabral, H., Ferreira, V.L. & Köhler, G. (2016): Revision of Philodryas mattogrossensis with the revalidation of P. erlandi (Reptilia: Squamata: Dipsadidae). Salamandra 52 (4): 293–305.

Motte, M., Cacciali, P. & Köhler, G. (2016): Leptodactylus chaquensis (Amphibia: Leptodactylidae): predación sobre ranas de la familia Hylidae. Boletín del Museo Nacional de Historia Natural del Paraguay 20 (2): 93–97.

Cacciali, P., Morando, M., Medina, C. D., Köhler, G., Motte, M. & Avila, L. J. (2017): Taxonomic analysis of Paraguayan samples of Homonota fasciata Duméril & Bibron (1836) with the revalidation of Homonota horrida Burmeister (1861) (Reptilia: Squamata: Phyllodactylidae) and the description of a new species). PeerJ 5:e3523; DOI 10.7717/peerj.3523.

Cacciali, P., Martinez, N. & Köhler (2017): Revision of the phylogeny and chorology of the tribe Iphisini with the revalidation of Colobosaura kraepelini Werner, 1910 (Reptilia, Squamata, Gymnophthalmidae). ZooKeys 669: 89-105. https://doi.org/10.3897/zookeys.669.12245

Cacciali, P., Morando, M., Avila, L. J. & Köhler, G. (2018): Description of a new species of Homonota (Reptilia, Squamata, Phyllodactylidae) from the central region of northern Paraguay. Zoosystematics and Evolution 94 (1): 147–161. DOI 10.3897/zse.94.21754

Köhler, G. & Hedges, S.B. (2015): Case 3672. Anolis chlorocyanus Duméril & Bibron, 1837 and Anolis coelestinus Cope, 1862 (Reptilia, Squamata): proposed conservation of the specific names and designation of a neotype for A. chlorocyanus. Bulletin of Zoological Nomenclature 72(1).

Köhler, G. & S.B. Hedges (2016): A revision of the green anoles of Hispaniola with description of eight new species (Reptilia, Squamata, Dactyloidae). Novitates Caribaea 9: 1-135.

Köhler, G., Rodriguez-Bobadilla, M.J. & Hedges, S.B. (2016): A new dune-dwelling lizard of the genus Leiocephalus (Iguania, Leiocephalidae) from the Dominican Republic. Zootaxa 4121 (5): 517–532.