Herp Lecture

What does Dorsal mean?

on the back

What does Ventral mean?

belly side

What is SVL?

Snout Vent Length (This is used because the tail of many lizards and snakes and other herps can vary considerably among populations so to get an accurate measurement herpetologist only measure snout to length)

What is the male reproductive organ called in reptiles?

hemipenes

What makes keeled scales different from other scales?

Keeled scales are lifted up from body

What does Gravid mean?

egg bearing

Characteristics of Linnean taxonomy?

1. implies categories

2. provides information about similarity that reflects evolutionary history

Characteristics of Evolutionary Taxonomy?

1. Assumes that similarity reflects homology

2. Results in evolutionary "trees" that reflect both degrees of relatedness and time

What is a holotype?

a single type specimen upon which the description and name of a new species is based.

What is a syntype?

any one of two or more specimen that are listed in the species description

True or False: Amphibians are Amniotic

False, they are Anamniotic

True or False: Reptiles are Amniotic

True

What important periods are included withing the Paleozoic Era?

1. Cambrian(590- 550mya)

2. Silurian( 438- 408mya)

3. Devonian(408-360mya)

4. Carboniferous(360-285mya)

5. Permian(286-245mya)

What arose during the Devonian Period?

The first tetrapods and first amphibians

What arose during the Carboniferous period?

THe first reptiles

What is the closest living relative of tetrapods?

lungfishes

What do Hox genes regulate in embryos of jawed vertebrates and tetrapods?

Limb development

Features of Early Tetrapod Respiration

• Lungs appeared early in the evolution of bony fishes

• Developed as accessory respiratory structures for gaseous exchange in anoxic waters.

• The buccal-force pump replaced a passive pump mechanism.

- A trait common to Amphibians

- Buccal pump important to calling in frogs

• Thus, respiratory precursors for terrestrial life were present in aquatic tetrapod ancestors.

Features of Early Tetrapod Feeding

• Primarily inertial feeding.

• Feeding in water was easier due to food buoyancy.

• Several skull modifications were necessary for terrestrial feeding.

• Snout and jaws elongated, intracranial joint locked and the primary palate became a broader and solid bony plate

Features of Early Tetrapod Skin

• The skin of larval amphibians and fish is similar. 2- 3 layer epidermis with slime (mucous) coat.

• Adult amphibian skin very different from fish ancestors

- 5-7 layer epidermis

- 2 basal epidermal layers

• External layers have keratinization (likely for protection).

Features of Early Tetrapod Sensory Organs

• Shift from aquatic to aerial perception.

• No more lateral line systems that only function in water.

• Appearance of outer and middle ear structures

• Sound travels much better on land (less dense medium).

• Eye changes to sharpen focus for long distance sight (difficult in dark/deep water).

• Nasal passages became dual-channel and were modified for olfaction.

What is included within Lissamphibia?

All three modern groups of amphibians

How long ago did true frogs appear on earth?

about 190mya but froglike vertebrates are known from 200-300mya

What extinct organism from the Permian period is referred to as the "frogmander"?

Gerobatrachus

What extinct organism was the first true frog?

Triadobatrachus massinoti

What are the three orders of modern amphibians?

1. Caudata (salamanders)

2. Anura (frogs and toads)

3.Gymnophiona (caecilians)

What family of caecilians are very primitive, are oviparous, and have a true tail?

Rhinatrematidae

What two families of caecilians have eyes on tentacles, and are both oviparous and viviparous?

1.Scolecomorphidae

2.Herpelidae

What family of caecilian has the largest known caecilian species?

Caeciliidae

What is unique about Tennessee referring to the state's salamander diversity?

Tennessee has more salamander species than in Europe and Asia combined

Caudata characteristics

• Long tails & elongate bodies

• Size ranges from

• 2 pairs of legs (most species) about equal in size

• Skin is smooth without scales, skin is moist (mucous glands) and is a good respiratory surface

• Some produce toxic secretions (often brightly colored)

• Some have specialized pheromone-glands

• Carnivores: eat mostly invertebrates

What clade do Birds, Crocodylia, and Non- Avian Dinosaurs, and possibly turtles belong to?

Archosaurs

What reptile groups are included under Lepidosaurs?

Squamates and Tuataras

What is the Permian-Triassic extinction?

About 250 mya. The biggest. Probably a comet or asteroid impact, but could have been caused by a large release of methane gas from the ocean bottom. Around 95% of all marine species went extinct. So did about 70% of known plants, insects, and other land species

What era was known as the age of the dinosaurs?

Mesozoic

What appeared during the Mesozoic Era?

1. The first mammals

2.first dinosaurs

When did the first turtles evolve?

during the Triassic period.

What appeared during the Jurrassic period?

The first true frogs and salamanders

When did Squamates first appear?

They appeared during the Cretaceous period

What are Saurischians?

lizard-hipped dinosaurs

What are Ornithischians?

bird-hipped dinosaurs

What order are turtles in?

Testudines

• 14 families with ~300 extant species, diverse ecology: marine, freshwater, and terrestrial

Earliest known turtle?

Eunotosaurus

What makes Odontochelys semitestacea so important?

is thought to be the organism the turtle body plan originated from

Traits of Crocodilians

•Crocodiles have changed little in 200 million years = a testament to the success of their design.

•All crocodiles have teeth set in sockets

• Have a complete palate which enables them to breathe even if the mouth is filled with water or food.

•All possess a four chambered heart

•Armored dorsum from osteoderms- bony plates

What are the three families of Crocodilians?

1. Alligatoridae

2. Crocodilidae

3. Gavialidae

Characteristics of Tuataras

• Only two species on islands off New Zealand

• Large (1.3 kg) lizard-like tuataras diverged early within the lepidosaurian clade rhynchocephalian and squamata split (220 MYA)

• Live to be very old (80+ years)

• Conservation efforts in New Zealand to protect habitat and manage/augment populations

• While adult females are breeding naturally, they only lay eggs every 4 years

Characteristics of Lepidosauria

• Transverse cloacal slit (vent)

• Full body ecdysis (skin-shedding), outer layers shed one at a time

• Breakage planes in the tail vertebrae

• ...but tuatara are a deep, uniquely different lineage (different order!), with characteristics not found in squamates

• e.g., dentition, bone structure,

Subgroups of Squamata

1. Gekkonidae

2. Scincidae

3. Teiidae (numerous species are parthenogenic)

4. Amphisbaenians (mostly limbless lizards)