Vertebrate Zoology - Practical Work - V. V. Kuibida - 2007

MODULE 3. Class Reptilia

IDENTIFICATION OF REPRESENTATIVES OF THE CLASS REPTILIA

Materials and Equipment

Required for the work:

1. Aquatic landing nets, one per 5 students; small bags and containers for storing collected specimens.

2. One or two representatives of each reptile genus.

3. A set of equipment (hand lens, Vernier caliper, ruler, forceps) — one set per team.

4. Identification keys for reptiles.

Lesson Plan

1. To master The Use of the reptile identification key. To familiarize students with the diagnostic features of identified species using specific specimens.

2. To introduce families, genera, and individual representatives of reptiles. To identify the most characteristic members of the herpetofauna of the Pereiaslav region.

3. To learn and master the Latin names and Main characteristics of 10 reptile species.

4. To explain 5 common (folk) names of reptiles based on their body shape, size, habitat types where these species occur, etc.

Execution of the Task

1. Catch reptiles inhabiting a specific region. Conducting a separate excursion solely for studying reptiles is generally impractical. The herpetofauna of a region can be studied alongside the batrachofauna, or during excursions dedicated to other animal groups. Lizards and slow worms are caught by hand, while turtles and grass snakes in the Water are caught using a net. Lizards are often caught using a Hair noose attached to a stick. Sometimes the noose is made of thin copper wire, fishing line, or synthetic thread.

The noose is carefully brought up to the animal's HEAD and pulled tight around its neck with a quick motion. It is important to remember that sudden movements and human shadows frighten reptiles, causing them to hide quickly. Lizards, along with amphibians, fall into pitfall traps where cylinders or Glass jars are set at the bottom. Snakes are caught using a stick with a fork at the end or a special herpetological hook. To avoid a snakebite, it is pressed against the ground behind the head, the neck is secured with the fingers of the right hand, and the tail is held with the left. The animal is lowered into a bag or jar tail-first, while the head is flicked inside with a quick motion. When identifying dead or preserved specimens of venomous snakes, one should keep in mind that viper venom does not dissolve in alcohol; therefore, pricking oneself on a venomous fang remains hazardous under any circumstances.

2. Work with tables and reptile identification keys. All captured reptiles are identified at the cAMP. The total body length and tail length of snakes and lizards are measured, and the data are recorded in a field notebook. Snakes may be marked by clipping abdominal scutes in a specific sequence to study their home ranges and mortality rates.

3. Examine the characteristic structural features and coloration of the reptiles and determine their species.

4. Record the main diagnostic features characteristic of the identified reptiles in your sketchbook.

5. Sketch the key features used to recognize each reptile species.

6. After Processing and verification of the identification by the practical instructor, the animals must be released back into the wild at their capture sites!

Rating Assessment of Knowledge and Skills

The maximum score for the "Reptiles" module is 10. Breakdown: for reptile species identification skills — 4 points; for Latin names and species characteristics — 4 points; for explaining the common names of reptiles — 2 points.

List of the main diagnostic features encountered in reptile identification

Before starting this practical, students should thoroughly review and learn the names of the head shields of lizards and snakes, which are used as key taxonomic characters during identification (Figs. 15, 16, 17).

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Fig. 15. Head shields of the sand lizard (dorsal view):

1 — rostral; 2 — internasal; 3 — frontonasal; 4 — loreal; 5 — prefrontal; 6 — frontal; 7 — frontoparietal; 8 — parietal; 9 — interparietal; 10 — occipital.

Fig. 16. Head shields of the sand lizard (lateral view):

1 — rostral; 2 — nasoprefrontal (nasal); 3 — postnasal; 4 — anterior loreal; 5 — posterior loreal; 6 — central temporal; 7 — tympanic; 8 — supralabials.

Fig. 17. Head shields of a snake (lateral view):

1 — rostral; 2 — nasals; 3 — internasals; 4 — loreal;

5 — preocular; 6 — supraocular; 7 — postocular; 8 — first row of temporals; 9 — second row of temporals; 10 — supralabials; 11 — suboculars.

In addition, students must familiarize themselves with the measurement and scale-counting techniques using the illustrations (Fig. 18).

Fig. 18. Diagram for counting scales around the midbody of a snake:

A — line indicating how to count the number of scales around the trunk; B — numbers from 1 to 17 indicate the scale-counting sequence.

Identification key to the Orders of Reptiles of Ukraine

Body oval, encased in a broad bony carapace covered dorsally with horny scutes. Order Testudines — Testudines. The fauna of Ukraine is represented by a single species — the European pond turtle — Emys orbicularis (L.).

Body elongate, covered with horny scales; limbs present or absent. Order Squamata — Squamata.

Identification Key to the Families of the Order Squamata — Squamata

Limbs present.

Eyelids movable. Head covered dorsally with large, symmetrically arranged shields. Tongue bifurcated and covered with rhombic, imbricate papillae.

Family Lacertidae — Lacertidae.

Eyelids immovable, fused into a transparent membrane (like a watch glass) covering the eye. Head covered dorsally with granular scales or numerous small, irregular polygonal shields. Tongue broad with an anterior notch.

Family Gekkonidae — Gekkonidae. Represented in the fauna by a single species — the Crimean gecko — Mediodactylus kotschyi danilewskii (St.), listed in the Red Data Book of Ukraine.

Limbs absent.

Belly scales are arranged in transverse rows. Eyelids are well developed.

Glass lizard family — Anguidae.

Belly scales are arranged in a single longitudinal row. Eyelids are undeveloped; eyes are covered with transparent corneal shields.

The body is thick, and the tail is short and conical. The head is flattened and has a more or less triangular or egg-shaped outline, covered dorsally with numerous small, regularly shaped shields or scales. The pupil has the shape of a vertical slit, and large venomous fangs are present.

Viper family — Viperidae. A typical representative of the fauna is the common adder — Vipera herus (L.).

The body is slender. The tail is long. The dorsal surface of the head is covered with 9 large, regularly shaped shields. The pupil is round. Large venomous fangs are absent.

Colubrid family — Соluhridae.

Identification key for the genera of the lizard family

The nostril is separated from the first supralabial shield by a wide gap, and its opening is located at the apex of a small tubercle formed by the nasal shields. The frontal shield features a more or less deep longitudinal groove. Racerunner genus — Еrеmіаз.

The fauna of Ukraine includes only a single species — desert racerunner — Е. arguta (Раll.).

The nostril touches the first supralabial shield, occasionally separated by a very narrow gap. The nostril opening does not rise above the level of the surrounding shields. Head shields, including the frontal one, lack longitudinal grooves.

Lizard genus — Laсerta.

Identification key for the species of the lizard genus.

The head is noticeably flattened dorsoventrally. The maximum height of the head is equal to 0.5–0.7 of its width.

Distinct light stripes extend along the sides of the body from the head. The intermaxillary shield reaches the nostril. Crimean lizard — L. tauriсa (Pall.).

Indistinct dark stripes run along the sides of the body from the head. The intermaxillary shield does not reach the nostril.

Rock lizard — L. saxicola (Еvеrsm.).

The head is not flattened dorsoventrally. The height of the head is equal to 0.8–1.0 of its width.

The hind FOOT is longer than the head.

The tail gradually tapers toward the tip. Its length is at least twice the length of the head and trunk combined. There are 2 or 3 postnasal shields. The hind legs, when stretched forward, reach the armpit.

European green lizard — L. viridis (Lаuг.).

The tail in its first half or third is quite thick, almost cylindrical, and then abruptly tapers toward the end. The tail length is less than twice the length of the head and trunk combined. There is a single postnasal shield. The hind legs, when stretched forward, do not reach the armpit.

Viviparous lizard — L. vivipara (Jaq.).

The hind foot is shorter than or approximately equal to the length of the head.

Sand lizard — L. agilis (L.).

Identification key for the genera of the family Anguidae

Deep Skin folds run along the sides of the body from the head to the cloacal opening; scales are rhomboid, with keels on the tail. Genus Glass Lizard — Oрhisaurus.

Represented in the fauna by a single species only — the Sheltopusik — O. aрodus (Раll.), listed in the Red Data Book of Ukraine.

No skin folds along the sides of the body; scales are rounded and smooth.

Genus Slowworm — Anguis.

Represented in the fauna of Ukraine by a single species only — the Slowworm — А. fragilis (L.).

Identification key for the genera of the family Colubridae

There are no more than 19 scale rows across the midbody.

Scales on the dorsal side bear distinct longitudinal keels.

Genus Water Snake — Nаtrіх.

Dorsal scales are smooth.

No suborbital shield beneath the preorbital shield. There are 7 upper labial shields; the internasal shield extends far between the supranasals.

Genus Smooth Snake — Соrоnеllа.

Represented in the fauna by a single species only — the Smooth Snake — С. austriaca (Laur.), listed in the Red Data Book of Ukraine.

Identification key for the species of the genus Natrix

The suture between the rostrolateral and internasal shields is not shorter than the suture between the rostral and the first upper labial shield. Two rather large yellow spots are present on the sides of the head behind the Mouth.

Grass Snake — Nаtriх natrix (L).

The suture between the rostral and internasal shields is shorter than the suture between the rostral and the first upper labial shield. No yellow spots on the sides of the head.

Dice Snake — N. tеssеllаtа (Lаuг.).

Key to the identification of reptiles (after O. B. Kistyakivsky and I. I. Mazepa (1967), revised and supplemented)

Limbs absent.

Limbs present.

Movable eyelids present. At least six rows of scales across the belly.

Eyes covered with a transparent spectacle (brille), eyelids absent. Belly scales form a single row only.

A deep groove runs along the sides of the body. Sheltopusik (Crimean Mountains and Kerch Peninsula only).

There is no lateral groove along the body. Slowworm.

Head flat, triangular or egg-shaped, covered with numerous small scales above. Pupil vertical. Tail short, conical

Head elongated, covered with nine large shields above. Pupil round. Tail long

Lateral margin of the snout rounded. At least four rows of scales in front of the large frontal shield (Fig. 20). Common viper

Fig. 20. Heads of vipers: common (1) and steppe (2).

Lateral margin of the snout pointed. Only three rows of scales in front of the frontal shield. Steppe viper (primarily the steppe zone of Ukraine).

Large whitish-yellow or orange spots on the sides of the head (Fig. 21). General dorsal coloration nearly black or grey. Grass snake.

Fig. 21. Head of a grass snake.

No light spots on the sides of the head.

At least 21 rows of scales across the middle of the body.

No more than 19 rows of scales across the middle of the body.

Scales on the anterior part of the back with longitudinal keels.

At least two shields in front of the eye.

Scales on the anterior part of the back without keels. Only one shield in front of the eye.

Head unpatterned and uniform above. Three rows of dark spots extending along the back, sometimes merging into a zigzag stripe. Four-lined ratsnake (southern steppe zone and Crimea only).

Top of the head with a characteristic dark arch-like pattern. Four dark stripes extending along the back. Amur ratsnake / Pallas's ratsnake (southeastern Ukraine only).

Ventral shields forming a noticeable ridge along the sides of the body. Body coloration unpatterned and uniform. Aesculapian snake (southwestern Ukraine only).

Ventral shields do not form a ridge along the sides of the body. Dark longitudinal pattern present on the back. Leopard snake (southern Crimean Peninsula only).

Dorsal scales with longitudinal keels. Dice snake (mainly the steppe zone and Crimea).

Scales without keels

Belly typically copper-red, upper parts grey or brown, top of the head usually featuring a complex dark pattern (Fig. 22). No suborbital shield beneath the preocular shield. Smooth snake.

Fig. 22. Head of a smooth snake.

Coloration different, with a predominance of ochre or yellowish-brown hues. A small subocular scale is present beneath the preocular. Caspian whipsnake (found exclusively in the southern steppe zone and Crimea).

Body covered with a broad carapace. European pond turtle.

Carapace absent; body covered with scales

Head covered dorsally with small granular scales. Mediterranean gecko (restricted to the southern Crimean Peninsula).

Head covered dorsally with large, symmetrically arranged shields

Nasal opening located on a protuberance formed by the nasal shields. Frontal shield featuring a longitudinal groove. Upper parts grey with a white and black pattern. Sand lizard (steppe zone and Crimea).

Nasal opening not elevated above the surrounding shields. Frontal shield lacking a groove. Coloration different.

Head not flattened. Its height is equal to its width or amounts to 0.8 of the width.

Head strongly flattened. Its height amounts to 0.5—0.7 of the width.

Tail twice as long as the rest of the body. Coloration green with a blue throat and yellow underside, or brownish above and whitish below. Green lizard (predominantly the Right-Bank region of the steppe and forest-steppe zones of Ukraine).

Tail shorter. Coloration different.

Dorsum dark or blackish-brown, venter orange or yellow. Hind foot longer than the head. Viviparous lizard (Polissya and Forest-Steppe of Ukraine).

Dorsum green or light brownish-grey, venter greenish or white. Hind foot no longer than the head. Sand lizard.

Rostral shield touches the nostril. Crimean lizard (restricted to Crimea and the Black Sea region).

Rostral shield does not Touch the nostril. Rock lizard (restricted to the southern Crimean Peninsula).