Lab 5: Lepidosauromorpha: Matt Knestrick & Megan Thornhill

Lepidosauromorphs

The group Lepidosauria is located within Eureptilia and is sister to the Archosauromorphs. The Lepidosaurs are represented by members of Sphenodontida (extant Tuataras), Sauria (lizards), and Serpentes (snakes). Some synapomorphies that tie these groups together include :

· A transverse cloacal opening

· A notched tongue

· Full-body ecdysis

· Imperperforate columella

· Teeth attached to jaws

· The pelvic bones in adults are fused

· Fracture planes (septa) in caudal vertebrae

The division of Lepidosauria containing both Serpentes (snakes) and Sauria (lizards) is called Squamata. Squamates can thrive in a wide variety of climates, elevations, environments, and habitats and are found on every continent except Antarctica. The members of Squamata are linked by over 50 synapomorphies, however, some of the most outstanding and most easily recognizable include a fused premaxillae, fused parietals, reduced nasals, and well developed hemipenes. They also have the presence of a Jacobson’s organ which is separated from the nasal capsule, they possess femoral and pre-anal glands and exhibit and egg tooth at hatching.

In order to better understand the synapomorphies of Squamata, a Varanus skull was examined. By doing this the examples of a fused premaxilla and parietals could be easily distinguished. As well as the lack of vomerine teeth, which is another synapomorphy that links the Squamates.

The following are examples of some of the families present in Sauria, this is by no means an exhaustive list and there is an ongoing debate to the exact number of families present in Sauria. This is due solely to the debate over some subfamilies being promoted to families. We were given examples of the following in lab:

Family: Agamidae

Distribution: Africa, Asia, Australia

Characteristics: Members of this family are covered in juxtaposed scales and lack osteoderms. All members are also limbed and have at least

moderately long tails. These lizards also posses acrodont dentition. The example in lab was from the Agaminae subfamily

Family: Anguidae

Distribution: Americas, Southwest and Southern Asia, and Europe

Characteristics: Members of this family vary greatly in size and the limb

condition of members of this family can range from fully limbed to reduced limbs to a lack of limbs.They exhibit large non-overlapping scales and have osteoderms

present ventrally and dorsally on the trunk region. Most members of this family show a longitudinal ventrolateral groove that allows for expansion of the body for reproduction, breathing, and feeding. This family express

pleurodont dentition and the example seen in lab was a member of the subfamily Anguinae. This specific genus had developed limblessness, and a longitudinal fold was clearly visible.

Family: Chamaelionidae

Distribution: Middle East, Africa, India, Southern Spain, Sri Lanka, and

Madagascar

Characteristics: Members of this family posses strong lateral compression, zygodactyl feet, and a prehensile tail. They also exhibit a parietal shield over their neck region as well as independently moving eyes. The dentition on this family is acrodont, and they possess reticular papillae on their tongues.

Family: Gekkonidae

Distribution: Tropics, South America, Africa, Western North America

Characteristics: Small granular scales cover members of this family both dorsally and ventrally. Other scale variations include large tubricles as well as defined papillae on their tongues. Caudal autonomy is common in this family. This is often paired with a large distracting tail used for fat and water storage. One characteristic seen in many members of this family is the presence of lamellae or ‘scansors’ on the feet used for climbing. They also express pleurodont dentition.

Family: Helodermatidae

Distribution: Southwestern North America south along the coast of the Mexican

Pacific toward Guatemala

Characteristics: Typically large lizards with well developed venom glands, but no system with which to inject prey. They have typically thick skin and large bead like granular scales. Physically they have rather flattened heads, robust bodies, and a short heavy tail. Among members of this family show no caudal autonomy and their tongues

have filamentous papillae. They spend most of their time underground except for mating, eating, and etc.

Family: Iguanidae

Distribution: Americas, Madagascar, west-central Pacific Islands

Characteristics: This family shows a wide range in size and diversity. This family is very sexually dimorphic. They are mainly opportunistic feeders, but occasionally exhibit a change in diet during different life stages. Four subfamilies were exhibited in lab, these were:

1. Polychrotinae: This subfamily contains 8 genera. In this subfamily the males are typically larger and possess a gular flap but no femoral pores.

2. Phrynosomatinae: This subfamily contains 10 genera including an Ohio species (Sceloporus undulates-Northern Fence Lizard). This subfamily is sexually dimorphic with the males showing femoral pores.

3. Corytophaninae: This subfamily contains 3 genera and extend from Southern Mexico to northern South America.

They possess a very long tail and males do not exhibit femoral pores, but the males to have frills/crests on their head and/or back.

4. Iguaninae: This subfamily contains 8 genera and have a huge distribution. In this family the adults are mainly herbivorous and the juveniles are very opportunistic feeders. They have large keeled scales, have pleurodont

dentition, and possess caudal autonomy.

Family: Scincidae

Distribution: Huge distribution (Nearly worldwide)

Characteristics: They exhibit smooth cycloid overlapping scales, and typically possess osteoderms. Show long to moderately long tails and some may exhibit reduced limbs. This family is highly speciated and there are both oviparous and viviparous examples in this family. This family is where many Ohio apecies are classified. These include:

· Scincella lateralis (Ground Skink)

· Eumeces fasciatus (Five-lined Skink)

Eumeces laticeps (Broad-headed Skink)

· Eumeces anthracinus (Northern Coal Skink)

Family: Teiidae

Distribution: Northern United States to Argentina and Chile

Characteristics: Possess small granular scales on the dorsal surface, but large rectangular scales ventrally. They have typically long tails and show caudal autonomy. The example seen in lab was from the subfamily Teiinae. The dentition of members of this family is also pleurodont.

Family: Varanidae

Distribution: Africa (warm temperate and tropical), Asia, and Australia

Characteristics: They are venomous lizards and lack caudal autonomy. Typically large with highly defined limbs. The ventral scales are generally visibly larger than those located on the dorsal surface. This is the family that the largest living lizard, the Komodo Dragon, belongs.

Lab #5 Lepidosauria - Cait Falasco and Chris Koch

Lepidosauriamorphs.
They are one of the most diverse extant groups of Eureptilia and are sister to Archosauromorphs.

Lepidosauria includes Sphenodontida (tuatara), Sauria (lizards), and Serpentes (snakes) which all share these synapomorphies:

• A transverse cloaca opening
• Notches on their tongues "lingual prehension"
• Full-body ecdysis, the ability to shed all their skin
• Imperforate columella or "stapes" in their ears
• Jaws with teeth attached directly
• Adults with fused pelvic bones
• Caudal vertebrae with fracture planes or "septa"

Lizards and snakes (highly derived legless lizards) belong to a group called Squamata which are found in very diverse climates and habitats on all continents with the exception of Antarctica.
The top synapomorphies of this group are: fused maxillae; fused parietals; reduced nasals; missing vomerine teeth; special ulna-ulnare, radius-radiale, and ankle joints; developed hemipenes; saccular ovaries; separate Jacobson's organ from the nasal capsule; a lacrimal duct joined to the vomeralnasal duct; egg tooth hatching; and femoral and pre-anal glands.
The right portion of the illustration below shows the skeletal anatomy of a varanid lizard:
Lepidosauria Skull Anatomy: (a) left lateral, (b) dorsal, (c) occipital and (d) palatal views, based mainly on NHMG 8502 and NHMG 9317. Scale bars, 10 mm. A, angular; Ar, articular; Bo, basioccipital; D, dentary; Ec, ectopterygoid; Fr, frontal; J, jugal; L, lacrimal; Mx, maxilla; N, nasal; Ot, oto-occipital; P, parietal; Pa, palatine; Pm, premaxilla; Pfr, postfrontal; Po, postorbital; Prf, prefrontal; Pt, pterygoid; pt.f, pterygoid flange; Q, quadrate; So, supraoccipital; Sp, Splenial; Sq, squamosal; St, supratemporal; Su, surangular; V, vomer.
(Source=http://rspb.royalsocietypublishing.org/content/277/1679/331.full)

We observed the following families of squamates in class last week:

Family: Agamidae (Angleheads, Calotes, Dragon Lizards, and Allies)
Subfamiles: Agaminae and Leiolepidinae
Distribution: Africa, Asia and Australia.
Characteristics: Agamids are covered dorsally and ventrally by overlapping juxtaposed scales and do not have osteoderms dorsally or ventrally. All species are limbed and their tails are long to moderately long. The skull has paired nasals, postorbitals, squamosals, frontal and parietal. The specimen we looked at in lab was Draco from the Agaminae subfamily. Dentition of these lizards is acrodont.
The top species Draco on the right picture belongs to this family.

Family: Chamaeleonidae (Chameleons)
Subfamilies: 6 genera
Distribution: Africa, Middle East, Madagascar, Southern Spain, Sri Lanka and India.
Characteristics: Chameleons have strongly laterally compressed bodies, prehensile tails and zygodactylous feet. They have projectile tongues for capturing prey and independently moving eyes. Most species have small juxtaposed scales with no osteoderms dorsally or ventrally. Chameleons have acrodont dentition and their tongue is covered dorsally with reticular papillae.
The middle species in the picture to the right is in this family.

Family: Anguidae (Alligator Lizards, Galliwasps, Glass Lizards and Allies)
Subfamilies: Anguine, Anniellinae, Diploglossinae and Gerrhonotinae.
Distribution: Disjunct, Americas, Europe, Southwest and Southern Asia.
Characteristics: Anguids vary in size to very small to large and some possess limbs while others are limbless. Anguids have large non-overlapping scales with underlying osteoderms dorsally and ventrally on the trunk. Some taxa have a longitudinal ventrolateral groove or fold that allows for body expansion during breathing, feeding and reproduction. Some Anguids have caudal autonomy but not all taxa. The specimen we looked at in lab was Ophisaurus from the subfamily Anguinae. They exhibit extreme limb reduction with a well developed ventrolateral fold, but not all have developed leglessness. Dentition of these lizards is pleurodont.  The species on the left belongs to this family.


Family: Gekkonidae (Gekkos and Pygopods)
Subfamilies: Diplodactylinae, Eublepharinae, Gekkoninae and Pygopodinae.
Distribution: Pantropic on all landmasses.
Characteristics: Gekkonoids are covered dorsally and ventrally by small granular scales and some are occasionally interspersed with tubercles. No osteoderms occur ventrally on the trunk but some geckos possess osteoderms ventrally. Some have big distracting tails that store fat and water; caudal autonomy is common among Gekkonoids. Their tongue is covered dorsally with peg-like papillae and lacks lingual scales. The subfamilies we looked at in lab were Eublepharinae and Gekkoninae. They have a single parietal eye on top, spectacle eyelids and sceleral ossicles to adjust their real eyes' lenses. They also have "scansors" or "lamellae" that are useful for climbing. Dentition of these lizards is pleurodont.  The species on the left belongs to this family.

Family: Helodermatidae (Gila Monster & Mexican Beaded Lizard)
Subfamilies: One genus Heloderma with 2 species.
Distribution: Southwestern North America southward along the Mexican Pacific coast to Guatemala.
Characteristics: Helodermatids are large lizards and are the only lizards with well-developed venom glands. They have flattened heads, robust bodies, short limbs and short heavy tails. They have thick skin with rounded scales in rows covering the body. Scales are slightly larger and squarish ventrally compared to the dorsal scales. On the ventral side small non-articulate osteoderms are present with none dorsally. Caudal autonomy does not occur. Their tongues have filamentous papillae and the foretongue retracts into the hind tongue. They love eating eggs and spending time underground being antisocial! Dentition of these lizards is pleurodont.  The species on the right belongs to this family.

Family: Teiidae (Whiptail Lizards, Tegus and Allies)
Subfamilies: Teiinae and Tupinambinae
Distribution: Americas from northern United States to Argentina and Chile.
Characteristics: Teiids scales are small and granular dorsally but large, rectangular and juxtaposed ventrally. No osteoderms are present dorsally or ventrally on the trunk. Teiids have caudal autonomy and their tails are typically long. The dentition of these lizards is pleurodont. The specimen we observed in lab was Aspidoscelis from the subfamily Teiinae. The species on the left belongs to this family.

Family: Iguanidae* (Anoles, Iguanas, Allies)
Subfamilies: (8) Corytophaninae, Crotophytinae, Hoplocercinae, Iguaninae, Oplurinae, Phrynosomatinae, Polychrotinae, and Tropidurinae.
Distribution: Americas (Ohio!), Madagascar, west-central Pacific islands
Characteristics: Great diversity so wide range of sizes. Scales are large, keeled and overlapping dorsally and ventrally while some have small granular scales, but no osteoderms are exhibited. Very sexually dimorphic. Prominent femoral pores and gular flap in some males. Some change in diet between life stages but mostly opportunistic (insectivore juveniles and herbivorous adults). Exhibit prominent collars and long to moderately long tails. Caudal autonomy occurs through fracture planes in the caudal vertebrae. Dorsal coverage of tongue with reticular papillae without lingual scales and a non-retractable foretongue. Dentition of these lizards is pleurodont.
The species on the right belongs to this family.
*OHIO SPECIES: Pictured to the right: Sceloporus undulates garmani (Northern Fence Lizard).

Family: Scincidae* (Skinks)
Subfamilies: Acontinae and "Scincinae"
Distribution: Nearly worldwide (Ohio!)
Characteristics: Scales are cycloid and smooth, overlapping dorsally and ventrally throughout the trunk and have osteoderms. Limbs can be reduced. They exhibit long to moderately long tails and caudal autonomy is common. Their tongue has filamentous papillae with alternating, serrated, dorsal lingual scales and a non-retractable foretongue. There are both oviparous and viviparous genera. Dentition of these lizards is pleurodont.  The species on the left belongs to this family.
OHIO SPECIES: From top to bottom in the picture to the left: Scincella lateralis (Ground Skink), Eumeces fasciatus (Five-Lined Skink), Eumeces laticeps (Broad-Headed Skink), and Eumeces anthracinus (Northern Coal Skink).

Family: Varanidae (Monitors, Goannas and Earless Monitors)
Subfamilies: Lanthanotinae and Varaninae
Distribution: Warm temperate & tropical Africa, Asia, Australia.
Characteristics: They have a blood groove and are venomous lizards. They are generally large and thick-skinned with well-developed limbs. Scales are larger ventrally than dorsally and only have small ventral osteoderms in few species. Their tails are very long but do not have caudal autonomy (cannot regrow tail). Their tongue has filamentous papillae without lingual scales and foretongue that is retractable into the hind tongue. Dentition of these lizards is pleurodont.  The species to the right and below are members of this family.
We'll leave you with this picture of Komoto Dragons (Varanidae) chowing down on some prey much larger than themselves, an ox.

Lab 5: Lepidosauria part 1: Sphenodontida & Sauria (Paluh and Harrington)

In this week’s lab we began looking at lepidosaurs. Lepidosauria includes the tuatara, lizards, and snakes. Some general characteristics of lepidosaurs include transverse vents, notched tongues, full-body ecdysis, imperforate collumellas, and fused pelvic bones. In lab, we focused exclusively on lizards, which are members of Squamata, the clade that includes lizards and snakes. Squamates generally have fused premaxillae, reduced nasals, fused parietals, no vomerine teeth, specialized wrist and ankle joints, well-developed hemipenes, Jacobson’s organs separated from the nasal capsule, and an egg tooth. In a phylogenetic context, snakes are derived lizards, and so Sauria, which once included only non-snake lizards, must be expanded to include Serpentes (snakes). With that said, it is still often useful to make a practical distinction between the “lizards” and snakes, and in this lab we focused exclusively on the non-snake lizards.

Varanus Skull Anatomy:

Pores and Caudal autotomy: Many lizards have glandular pores present anterior to the cloaca (precloacal pores) or on the underside on the hind leg (femoral pores). These pores are typically found on male lizards, and, if present, will be smaller in females than males of a species. Caudal autotomy (self-cutting) is a common defense mechanism in many saurians. If a predator attacks a lizard that is capable of caudal autotomy, it will purposely remove it's tail from it's body to distract the predator so it is able to escape.

Selected Lizard Families:

Family Agamidae (angleheads, calotes, dragon lizards, and allies; 2 subfamilies): Agamids are covered dorsally and ventrally by overlapping or granular and juxtaposed scales. Agamids lack osteoderms on the trunk. All species are limbed. Most species have moderately long to long tails that typically lack fracture planes (for autotomization). Agamids also possess acrodont teeth (teeth anchored to surface of jaw). We had a specimen of Draco from the subfamily Agaminae. Agamines are mostly terrestrial to semiarboreal that have diverse body shapes, including that of the unique gliding lizard, Draco. Agamines are primarily diurnal and most, if not all, are oviparous.

Family Chamaeleonidae (chameleons; 6 genera with 171 species): Chamaeleonids have laterally compressed bodies, prehensile tails, head casques covering their necks, and independently moveable eyes. In addition, their feet are xygodactylous, with the digits 1-2-3 and 4-5 fused in the manus and digits 1-2 and 3-4-5 fused in the pes. Tails are short to long and teeth are acrodont (Chamaeleonidae + Agamidae = Acrodontia). Chamaeleonids are primarily highly arboreal, and much of their morphology is adapted for an arboreal lifestyle. Chamaeleons tend to stalk their prey, moving in sync with movements of branches and leaves. They stalk prey, focus on it with both eyes, and then use their exceptionally long tongues to capture their prey and bring it back to the mouth. Chamaeleonids may be viviparous or oviparous.

Family Iguanidae (anoles, iguanas, and allies; 8 subfamilies): Iguanidae is a highly diverse family, and the lower-level taxonomy within this family is somewhat unresolved. Iguanids range from small to large. They may have large, overlapping, keeled scales or small, granular scales covering the body, with no osteoderms present on the trunk. Tails are usually moderately long to long, with fracture planes for caudal autotomy present. We examined specimens of the subfamilies Polychrotinae, Phrynosomatinae, Corytophaninae, and Iguaninae. Polychrotines are primarily arboreal and diurnal, and typically consume arthropod prey. Male polychrotines are typically larger than females. Phrynosomatines primarily dwell in arid environments and feed on arthropod prey. Most phrynosomatines are oviparous, but some are viviparous. Sceleoporus undulatus garmani, a lizard native to Ohio, is a member of Phrynosomatinae. Corytophanines are primarily arboreal, and are found in dry scrub forest to wet rain forest. Corytophanines are casque-headed, slender bodied, and have long limbs and tails. Corytophanines may be oviparous or viviparous. Iguanines are primarily large lizards and range from marine/rock-dweller to arboreal species. Iguanines are almost exclusively herbivorous, and all are oviparous.

Family Gekkonidae (geckos and pygopodids; 4 subfamilies): Gekkonids are typically covered by small, granular scales periodically interrupted by tubercles, and lacking osteoderms on the trunk. Many gekkonids have scansors/lamellae present on their toe pads for climbing. The tail is typically moderately short to long. Teeth are pleurodont. Some gekkonids are elongated and snake-like (Pygopodinae). We observed specimens from the subfamilies Eublepharinae and Gekkoninae. Eublepharines are almost all terrestrial, nocturnal, insectivores that lay eggs in clutches of two. Gekkninae is a highly diverse group (more than 800 species), and have a variety of morphologies and ecologies. All gekkonines are oviparous, and most are insectivorous.

Family Teiidae (whiptail lizards, tegus, and allies; 2 extant subfamilies): Teiids have small, granular dorsal and lateral body scales, and large, rectangular, juxtaposed scales arranged in rows on the ventral surface of the body. They have no osteoderms on the trunk. They typically have long tails that have fracture planes for autotomization. We observed two specimens of Aspidoscelis from the subfamily Teiinae. Teiines have a streamlined body, long, whip-like tail, and long limbs. They are active at relatively high temperatures, and are active foragers that feed on arthropods. All teiines are oviparous, and some are parthenogenetic.

Family Scincidae (skinks; 2 subfamilies): Scincids are typically by overlapping scales that are underlain by osteoderms on the dorsal and ventral sides of the trunk. Some taxa have limb reduction that can be quite strong. Tails are moderately long to long, and many skinks have fracture planes for autotomization. We observed specimens of Plestiodon fasciatus, Plestiodon laticeps, and Scincella lateralis, all of which are Ohio-native species found in the subfamily Scincinae. Plestiodon anthracinus anthracinus is also native to Ohio and in Scincinae. Scincinae is a very diverse (~1200 species) and poorly resolved clade. As such, it is difficult to make generalities about the biology of scincines. Scincines are oviparous or viviparous, with some exhibiting the highest level of matrotrophy seen in reptiles.

Family Anguidae (alligator lizards, galliwasps, glass lizards, and allies; 4 subfamilies): Anguids are lizards that have small-well developed limbs or are limbless. They are heavily-armored with large, overlapping scales underlain by osteoderms on the trunk. Many anguids have a longitudinal, ventrolateral fold that allows for body expansion for breathing, feeding, and reproduction that might otherwise be limited by their armor. Most anguids have tails that have fracture planes for caudal autotomy. We observed a specimen of Ophisaurus from the subfamily Anguinae. Anguines are elongate, limbless lizards with ventrolateral folds. They are typically found in scrub or open habitats with dense ground coverage and typically prey on invertebrates.

Family Helodermatidae (gila monster and Mexican beaded lizard; 1 genus, Heloderma, with 2 species): Helodermatids have well-developed venom glands. They have stout, robust bodies, and are covered in rounded, bead-shaped scales. Ventrally, osteoderms are present on the trunk. Helodermatids are primarily crepuscular to nocturnal, and tend to spend most of their time in burrows when not foraging or searching for mates. They feed on a variety of mammals, birds, reptiles, eggs, and invertebrates.

Family Varanidae (monitors, goanna, and earless monitors; 2 subfamilies with one genus each; 64 species): Varanids are typically large lizards, and the largest extant lizard, Varanus komodoensis, is a varanid. The body is covered with small, circular scales with slightly larger scales on the ventral surface that resemble smaller versions of the ventral scales of teiids. Ventral osteoderms are present in some species. We observed a specimen of Varanus, the only genus in the subfamily Varaninae, which includes all varanids except for one. Varanines are primarily active predators with relatively small heads, long necks, and long, robust bodies. Smaller varanines prey primarily on small vertebrates and arthropods, while larger species may feed on fairly large vertebrates.

Lab 5: Lepidosauria part 1: Sphenodontida and Sauria (Michele and Brad)

Lepidosauria: Sphenodontida and Sauria

Glass Lizard (Family: Anguidae Genus: Ophisaurus )

Sphenodontida & Sauria are within the major lineage Lepidosauromorpha. Some of the synapomorphies that are present within this lineage are a transverse cloacal vent, a notched tongue (along with lingual prehension to capture prey), full-body ecdysis, an imperforate columella, teeth that are attached to the jaws, adults with fused pelvic bones, and fracture planes or septa within caudal vertebrae. Sphenodontida and squamates diverged in the early Late Triassic.

Squamata

Squamates have many derived features, including well developed hemipenes, saccular ovaries, Jacobson's organ, femoral and preanal glands, and an egg tooth for hatching. Lizards and their snake descendants are the only non-extinct squamates. Excluding snakes, there are about 4450 species of lizards within approximately 19 families (there may be as many as 36 families). Controversy surrounds the number of lizard families there actually are, because many scientists believe many subfamilies should be raised to family status, especially within the Iguanidae. For this lab, we examined the anatomy of a Varanus skull. we had unknown lizards on our tables and identified them to family and looked at some of their major features.


Varanus skull anatomy

Some of the bones in Dorsal View:

Light Green = Septomaxilla
Grass Green = Jugal
Orange = Nasal
Dark Green = Quadrate
Pink = Maxilla
Light Blue= Premaxilla
Yellow = Parietal

Ventral View:

Purple = Basisphenoid
Pink = Maxilla
Blue = Post orbital/post frontal
Dark Green = Quadrate
Red = Pterogoid
Yellow = Palatine






Representatives from selected lizard families (Identified unknowns from lab):

Family: Agamidae
Subfamilies: Agaminae (52 genera), Leiolepidinae (2 genera)

Distribution: Old world - Africa, Asia, Australia

Characteristics of family: Acrodont dentition, highly arboreal, and feed on arthropods. This amazing genus is able to glide using dorsal skin flaps supported by elongate ribs, and control the direction of their gliding.

Subfamily pictured: Agaminae
Genus: Draco









Family: Anguidae

Subfamilies: Anguinae (3 genera), Anniellinae (1 genus), Diploglossinae (3 genera), Gerrhonotinae (6 genera)

Characteristics of family: Limbed to limbless lizards, heavily armored with non-overlapping scales, osteoderms underlie the ventral and dorsal scales on the trunk, interclavical is absent or cruciform, pleurodont dentition.

Distribution: Americas, Europe, southwest Asia and southern Asia.

Subfamily in lab: Anguinae



Family: Chamaelionidae

Pictured below: Genus: Chamaeleo
Genera: Bradypodion, Brookesia, Calumma, Chamaeleo, Furcifer, Rhampholeon

Characteristics of family: Xygodactylous feet, head casques covering their necks, projectile tongues, independently moving eyes, prehensile tail, acrodont dentition.

Distribution: Africa, Middle East, Madagascar, southern Spain, Sri Lanka, India

Family: Gekkonidae

Subfamilies: Diplodactylinae (20 genera), Eublepharinae (6 genera), Gekkoninae (79 genera), Pygopodinae (7 genera)

Distribution: On all continents, widespread

Family Characteristics: Second most speciose family of lizards, behind skinks, covered by small, granular scales interspersed with tubercles, no osteoderms dorsally, pleurodont dentition. The Leopard gecko, Eublepharus macularius, (pictured to the left) has extra fat and water stored in the tail, which is believed to confuse predators into believe their tail is actually their head.

Below is Hemidactylus frenatus, the Common House gecko. Originally from southeastern Asia and now an invasive in America.










Family: Helodermatidae

Genus: Heloderma

Family Characteristics: Large bodied (300 - 500 mm SVL), the only lizards with venom glands, broad & flattened heads, robust bodies, thick skin with rows of rounded scales that look like beads (see the picture to the right). Pleurodont teeth.

Distribution: Southwestern North America, along the pacific coast to Guatemala.









Mexican beaded lizard: Heloderma horridum






Family: Iguanidae

Pictured Below: Northern Fence Lizard (Sceloporus undulates garmani), male has dark pattern on belly, female does not.
Subfamilies: Corytophaninae (3 genera), Crotaphytinae (2 genera), Hoplocercinae (3 genera), Iguaninae (8 genera), Oplurinae (2 genera), Phrynosomatinae (10 genera), Polychrotinae (8 genera), Tropidurinae (11 genera).

Family Characteristics: Covered dorsally and ventrally by large, keeled, overlapping scales, others with small granular scales, tail is usually long, dentition is pleurodont.

Distribution: Americas, Madagasca, west-central Pacific islands



Subfamily: Iguaninae, Iguana iguana











Subfamily: Corytophaninae Genus:Basiliscus








Subfamily: Iguaninae Genus: Ctenosaura









Family: Scincidae

Subfamilies: Acontinae (4 genera), Scincinae (133 genera)

Family Characteristics: The most diverse family of lizards, covered with overlapping scales dorsally and ventrally, osteoderms underlie the scales, body forms range from strong limbed to no external limbs, autotomous caudal vertebrae have a fracture plane anterior to the transverse process, pleurodont dentition.

Distribution: Nearly worldwide.


Pictured above (starting from top): Eumeces fasciatus - Five-Lined Skink, Eumeces laticeps - Broad-Headed Skink, Scincella lateralis -Ground Skink (displaying a tail lost due to caudal autotomy)


Family: Teiidae

Subfamilies: Teiinae (6 genera), Tupinambinae (4 genera), Chamopsinnae (extinct clade), Polyglyphanodontinae (extinct clade)

Family characteristics: Dorsal and lateral scales are small and granular, but ventral scales are large, juxaposed, and arranged in transverse rows, no osteoderms, tail is autotomous and usually long, pleurodont dentition.

Distribution: Americas, United states to Argentina and Chile

Cnemidophorus tesselatus (subfamily: Teiinae)

Family: Varanidae

Subfamilies: Lanthanotinae (1 genus: Varanus), Varaninae (1 species: Lanthanotus borneesis)

Family Characteristics: Generally large, thick skin with rows of small, rounded scales circling the body, pectoral girdle has a t-shape, tail is very long, pleurodont dentition.

Distribution: Warm temperature and tropical Africa, Asia, and Australia

Subfamily: Varaninae Genus: Varanus

Species of lizards found in Ohio:
Family: Iguanidae
Sceloporus undulates garmani - The Northern Fence Lizard
Family: Scincidae
Scincella lateralis -Ground Skink
Eumeces fasciatus - Five-Lined Skink
Eumeces laticeps - Broad-Headed Skink
Eumeces anthracinus anthracinus - Northern Coal Skink