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The abdominal skeleton of tropidurid lizards (Squamata : Tropiduridae)

Smithsonian Libraries
Morphological variation in the abdominal skeleton of Tropiduridae was examined from radiographs and cleared-and-stained specimens of 61 species. Based on the numbers of xiphisternal and postxiphisternal inscriptional ribs, as well as the presence of inscriptional ribs articulating ventromedially, seven patterns of rib attachment are described. The distribution of these patterns among the species studied reveals intra- and interspecific variation, which indicates that the abdominal skeleton of lizards is a good source of fixed and polymorphic characters for phylogenetic analyses.

New species of Stenocercus (Squamata : Iguania) from the Andes of central Peru with a redescription of Stenocercus variabilis

Smithsonian Libraries
A new species of Stenocercus is described from the eastern slopes of the Andes in central Peru, Departamentos Ayacucho and Huancavelica. It differs from other Stenocercus by the combination of the following characters: scales on posterior surface of thighs granular, lateral body scales imbricate and keeled, vertebral row of enlarged scales present, gular scales unnotched, neck folds present, three caudal whorls per autotomic segment, postfemoral mite pocket absent, dorsal ground color gray or brown, without a black shoulder patch in males. Specimens of the new species have been misidentified as Stenocercus variabilis, which occurs allopatrically in Departamento Junin.

Phylogeny of hoplocercine lizards (Squamata: Iguania) with estimates of relative divergence times

Smithsonian Libraries
Hoplocercine lizards form a clade of 11 currently recognized species traditionally placed in three genera (Enyalioides, Hoplocercus, and Morunasaurus) that occur in the lowlands on both sides of the Andes between Panama and the Brazilian Cerrado. We analyze 11 mitochondrial and two nuclear loci using probabilistic methods and different partitioning strategies to (1) infer the phylogenetic relationships among species of Hoplocercinae, (2) examine amounts of inter- and intraspecific sequence divergence, (3) address monophyly of four species, (4) test previous phylogenetic hypotheses, and (5) estimate divergence times. Our preferred hypothesis places H. spinosus as the sister taxon to all other species of hoplocercines, with M. annularis nested within Enyalioides. Species with multiple samples are monophyletic except for Enyalioides oshaughnessyi, which is paraphyletic relative to an undescribed species of Enyalioides. All previously published phylogenetic hypotheses for hoplocercines are rejected. Monophyly of Enyalioides cannot be rejected and, consequently, the position of Morunasaurus remains unclear. The most recent common ancestor of Hoplocercinae probably occurred east of the Andes; western taxa included in our analyses originated from at least two separate colonizations whether pre- or post-dating vicariance resulting from uplift of the Andes.

Resurrection of Stenocercus torquatus Boulenger, a spiny-tailed iguanid lizard (Squamata : Iguania) from Peru

Smithsonian Libraries
We resurrect and redescribe Stenocercus torquatas from the Andes of central Peru in departamentos Junin and Pasco at elevations between 800 and 1800 m. This species was erroneously synonymized with Stenocercus crassicaudatus, which occurs allopatrically in the Andes of southeastern Peru, departamento Cusco. In addition to several scale counts, Stenocercus torquatus differs from S.crassicaudatus in having a black antehumeral collar, two black transverse bands anterior to the antehumeral collar, a shorter tail, the ability to change color, and an arboreal life-style.

Cranial osteology of the Andean lizard Stenocercus guentheri (Squamata : Tropiduridae) and its postembryonic development

Smithsonian Libraries
In spite of the great diversity of iguanian lizards, detailed descriptions of their osteocrania and postembryonic development are rare. Herein, the adult cranial osteology of the tropidurid lizard Stenocercus guentheri and its postembryonic development are described based on cleared and double-stained and dry skeletal specimens from a single Ecuadorian population. The amphikinetic skull of S. guentheri is short and elevated and bears teeth on the premaxilla, maxillae, and pterygoids. Mandibular teeth are present on the dentaries. Ossification of the articular from Meckel's cartilage and growth of the parietal (ossification and investment of the frontoparietal fontanelle) are the most significant ontogenetic changes of the splanchnocranium and dermatocranium, respectively. The ossification of the cartilage separating the bones of the braincase is the most relevant postembryonic ontogenetic event of the neurocranium. The number of teeth does not vary ontogenetically and replacement teeth are present throughout postembryonic life. This study includes a list of the osteocranial characters of Stenocercus that have been used in systematic studies, as well as a discussion of functional morphology and kinesis. (C) 2002 Wiley-Liss, Inc.

‘Dwarf Dragons’ of the Andean Rainforests

National Museum of Natural History
Scientists recently discovered three new species of lizards that look like little dragons in South America! A new paper was published in ZooKeys by Omar Torres-Carvajal of the Museo de Zoología QCAZ, Ecuador; Kevin de Queiroz of the Smithsonian’s National Museum of Natural History, and Pablo Venegas, CORBIDI, Peru. We...

New Dwarf Dragons Have Been Found in the Andes

Smithsonian Magazine

Wander deep into the cloud forests of South America, and you might just encounter a dragon. Also known as woodlizards, dwarf dragons are diverse reptiles that come in shocking shades of neon green and bloody red. Some look strikingly like miniature versions of their mythological namesake, with flaming scarlet eyes and armor-like spikes seemingly straight out of a painting of Saint George battling his nemesis. 

Now, three newly discovered species join the dragons’ ranks, hailing from a well-known biodiversity hotspot in the Andean cloud forests of Peru and Ecuador. As the lizards’ discoverers report this week in the journal ZooKeys, this raises the current species count for this group to 15. 

When Omar Torres-Carvajal began his postdoctoral research at the Smithsonian Institution in 2006, scientists knew of just a handful of dwarf dragon species. Herpetologists considered dwarf dragons to be one of the least diverse groups of South American lizards. But with a few forays into the forest, Torres-Carvajal quickly began proving that assumption wrong. Over the past seven years, he and his colleagues have discovered seven new species in Ecuador and Peru. On this latest collecting trip, they didn’t even have to look particularly hard before crossing paths with intriguing specimens. Scooping up several conspicuous dragons, which are active during the day, they immediately suspected they were on to something.  

The first thing the team did was compare those animals’ patterns, body shapes and sizes, eye color and more to attributes of previously collected species. They also compared DNA samples from the unidentified lizards to those in an existing database. These studies convinced the researchers that they did indeed have three new species. 

Enyalioides altotambo, the Alto Tambo woodlizard, was their first find. Named for the tiny village in northwestern Ecuador where it was collected, the males of this species have the look of a baby iguana. A female of the same species has a more chameleon-like appearance, with a tubular body and broader, flatter face. The Alto Tambo woodlizards differ from other dwarf dragons in that their scales are smooth and equally sized, rather than the usual hodgepodge of mismatched spikes and disks. 

The researchers found Enyalioides anisolepis, the rough-scaled woodlizard, on the forested slopes of the Amazonian Andes in southern Ecuador and northern Peru. E. anisolepis has a more traditional mythical dragon look, with a body and limbs covered in stud-like scales that project outward. The authors note that it comes in three color variations, ranging from black and bright green to brown to burnt orange.   

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Finally, they introduced Enyalioides sophiarothschildae, the Rothschild’s woodlizard. This scrappy reptile has a slender black-and-brown body tipped with bright green spikes. Its most characteristic feature is its “immaculate white labials and chin”—patches of bright scales around its mouth and neck, like a white-chinned cat. 

Almost certainly, these will not be the final additions to the book of South American dwarf dragons, the team says: “Woodlizards are fairly large and conspicuous, so it’s interesting that roughly half of the currently recognized species have been discovered in the last 10 years,” Kevin de Queiroz, Torres-Carvajal’s supervisor at the Smithsonian's National Museum of Natural History, said in an email. “This illustrates how much we still have to learn about South American reptiles.” 

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