Lab 6: Serpentes & Ophidia: Matt Knestrick & Megan Thornhill

Overview: In this lab, we examined the family of reptiles known as serpents. We examined skull specimen to show their unique skulls, and examine preserved and live specimen of a few major serpents families.

Skull

The skull photographed is that of the genus Crotalus. The skull exhibits both aglyphous and proeteroglyphous fangs. Aglyphous are typical fangs found in all serpents, while proteroglyphous are “front-fangs” found at the front of the mouth attached to to maxilla. This skull is an excellent example of the streptosytly seen in snakes. Streptostyly is a method of opening the mouth where the long jaw articulates on the quadrate bone. Because of the exaggerated jaw-quadrate bones on the snake (compared to humans or other mammals), snakes can open their mouths extremely wide to swallow prey that can be much bigger than their heads.

Familes

We studied 5 major families of snakes, as well as saw specimen native to Ohio.

Pythonidae

The pythons are Old world serpents, meaning that their distribution are in Africa, Asia, Indonesia, etc. They are aglyphous and are some of the largest snakes in the world.

Boidae

Boidea is the boa family. They are composed of two major subfamilies: Boinae and Erycinae, and have an old and new world distribution, occurring in Western N. America, The West Indies, S. Asia, and Madagascar. Like pythonidae, they are aglyphous.

Viperidae

The viper family has 4 major subfamilies: Azemiopi (1 genus), Viperinae (13 genera), and Crotalinae (26 genera). Subfamily Crotalinae are venomous, and mostly viviparous (live birth), although some are oviparous (lay eggs). Similarly, some have rattles, a derived condition, while others do not. They are long-lived, and have cranial infrared receptors associated with their loreal pits. Crotalinae have aglyphous fangs, as well as solenoglyphous ones. Solenoglyphous fangs are highly derived, hollow front fangs that are attached to a highly mobile maxilla bone.

There are also OH native species in the Crotalinae subfamily, such as:

Agkistrodon contortrix (Northern Copperhead)

Sistrurus catenatus (Eastern Massassauga)

Crotalus horridus (Timber Rattlesnake)

The second subfamily is Viperinae. Unlike Crotalinae, Viperinae have lost their loreal pits. They are ovi- and viviparous, and are terrestrial, nocturnal species. They also have a large old world distribution, including Africa, Asia, and Europe.

Elapidae

The Elapids are cobras, sea snakes, and death adders. There are over 60 genera, distributed from southern N. America to S. America, Africa, Asia, and the Indian and Pacific oceans. They are highly venomous, with no cranial infrared receptors. They have proteroglyphous fangs.

The subfamily Hydrophiinea includes sea snakes. These species have laterally compressed, paddle-like tails. They have lost their large, ventral scales, and are viviparous, although some are oviparous and lay eggs on land. The subfamily Elaphinae are the cobras, mambas, and sea cretes. They are Opheophagus, or snake eatere, and are mostly terrestrial and oviparous.

Colubridae

The Colubridae are one of the largest families of snakes. They are highly diverse “grab bags” or species. However, they are a monophyletic group, and are all typically non-venomous (at least to humans).

The first subfamily is Colubrinae. This is the most diverse subfamily, with over 100 genera. There are also many OH native species, including:

Opheodrys aestivus (Rough Green Snake)

Coluber constrictor foxii (Blue Racer)

Coluber constrictor constrictor (Northern Black Racer)

Pantherophis vulpinis (Fox Snake)

Lampropeltis triangulum (Eastern Milksnake)

Lampropeltis getula (Black Kingsnake)

The second subfamily, Natricinae, are semi-aquatic and entirely aquatic snakes. They are typically fish and amphibian food specialists. They also have many OH natives, including:

Nerodia sipedon (Northern Water Snake)

Regina septemvittata (Queen Snake)

Thamnophis sirtalis (Eastern Garter Snake)

Storeria dekayi (Brown Snake)

Storeria occipitomaculata (Northern Redbelly Snake)

The final subfamily is Dipsadinae. Dipsadinae have two different body types, depending on their activity during the day. Dirunal species typically have more robust, muscular bodies, while nocturnal species have more slender bodies. They are terrestrial and oviparous, and their clutch size is directly related to the size of the female. They are also Opisthoglyphous, meaning they have teeth in the rear of their mouths. They include the following OH native species:

Diadophis punctatus (Ringneck Snake)

Heterodon platyrhinos (Eastern Hognose Snake)

Carphophis amoenus (Worm Snake).

Lab 6: Lepidosauria Part II: Serpentes (Kelly and Maggie)

Squamata, which is composed of Sauria and Serpentes contains over 8,000 species. Sauria makes up most of this group; however, it is essential to recognize that snakes are very derived lizards. Currently, there are at least 16 families of snakes, but there may be as many as 23. As with other reptile groups, there is a family/sub-family debate: confusion lies over whether scientists should elevate sub-families to family level or leave them where they are.

An important distinction between snakes and lizards is cranial kinesis. Snakes are streptostylic, while lizards are not. This trait allows snakes to widely open their lower jaw.

Streptostyly and cranial kinesis in action.

In a snake, teeth lie on the dentary, maxilla, palatine, and lateral areas of the pterygoid. Most of these teeth are re-curved to more efficiently keep prey inside the mouth. Fangs are specialized teeth which only some snakes possess. These fangs can simply be grooved, or they can be specialized venom-delivery apparatuses. 

Aglyphous teeth.

Four major categories of teeth and fangs exist: 

1. Aglyphous snakes possess no fangs. They have typical, conical or laterally compressed, re-curved teeth. These fangless teeth are found in every type of snake. 

2. Opisthoglyphous refers to the condition of having rear fangs. This dentition is found in colubrid snakes. 

Solenoglyphous fangs and aglyphous teeth.

3. Proteroglyphous snakes display a front-fanged condition. These fangs are completely folded and are hollow in the center. This type of fang dentition is found in the family Elapidae.

4. The most derived type of snake fang is the solenoglyphous fang. These fangs are completely hollow. Snakes with this type of fang are able to retract (swing) their fangs down, allowing them to inject their prey with venom. This derived dentition is only found in the family Viperidae.

This lab was centered on 5 families of snakes: Pythonidae, Boidae, Colubridae, Elapidae, and Viperidae.

(* Indicates Ohio species in JCU collection)

A member of Pythonidae

Pythonidae:

Distribution: Sub-Saharan Africa, South and Southeast Asia to Australia.

Number of genera: 8

Characteristics and biology: Large to giant snakes; aglyphous; terrestrial and arboreal; some are semi-aquatic; all are oviparous.

Boidae:

Erycinae: Charina (rubber boa)

Distribution: Western North America to southern sub-tropical South America, West Indies, central Africa to South Asia, Madagascar, and Southwest Pacific islands.

Characteristics and biology: Small to large snakes; most have cranial infrared receptors in interlabial pits.

Subfamily: “Boinae”

Number of genera: 7

Characteristics and biology: Mostly arboreal; largest-bodied clade; all viviparous.

Erycine: Eryx (sand boa aka Celo)

 

 

Subfamily: Erycinae

Number of genera: 4

Characteristics and biology: Usually in semiarid to arid habitats; robust, cylindrical bodies, short tails, blunt heads, small eyes; predominately nocturnal; all are viviparous.

Colubridae:

Distribution: Worldwide, except Antarctica and oceanic islands

Characteristics and biology: Inclue aglyphous, opisthoglyphous and proteroglyphous taxa; paraphyletic.

Subfamily: Natricinae

Number of genera: 38

Characteristics and biology: Many are aquatic.

Ohio species:

*Nerodia sipedon sipedon (Northern Water Snake)

N. s. pleuralis (Midland Water Snake)

N. erythrogaster neglecta (Copperbelly Water Snake)

*Regina septemvittata (Queen Snake)

Thamnophis butleri (Butler’s Garder Snake)

*Thamnophis sirtalis sirtalis (Eastern Garder Snake)

T. radix radix (Eastern Plains Garder Snake)

T. sauritus sauritus (Eastern Ribbon Snake)

T. sauritus septentrionalis (Northern Ribbon Snake)

*Storeria dekayi wrightorum (Midland Brown Snake)

*S. dekayi dekayi (Northern Brown Snake)

*S. occipitomaculata occipitomaculata (Northern Redbelly Snake)

Virginia valeriae valeriae (Eastern Smooth Earth Snake)

Representatives of Natricinae (clockwise from left): Regina septumvitatta, Storeria dekayi, Nerodia sipedon sipedon, Storeria occipitomaculata, Thamnophis sirtalis sirtalis

Subfamily: Dipsadinae

Number of genera: Over 90

Characteristics and biology: Occur in all habitats.

Ohio species:

*Diadophis punctatus edwardsi (Northern Ringneck Snake)

*Heterodon platyrhinos (Eastern Hognose Snake)

*Carphophis amoenus amoenus (Eastern Worm Snake)

C. a. helenae (Midwest Worm Snake)

Representatives of Dipsadinae (L to R): Diadophis punctatus edwardsi, Heterodon platyrhinos, Carphophis amoenus

Subfamily: Colubrinae

Number of genera: More than 100

Characteristics and biology: Very diverse in body form; predominately oviparous.

Ohio species:

Opheodrys vernalis (Smooth Green Snake)

*O. aestivus (Rough Green Snake)

*Coluber constrictor foxii (Blue Racer)

C. c. constrictor (Northern Black Racer)

*Pantherophis obsoletus obsoletus (Black Rat Snake)

*P. vulpinus (Fox Snake)

*Lampropeltis triangulum triangulum (Eastern Milk Snake)

*Lampropeltis getula nigra (Black Kingsnake) 

Representatives of Colubrinae (clockwise from top left): Pantherophis obseletus obseletus, Lampropeltis triangulum triangulum, Lampropeltus getula nigra, Opheodrys aestivus, Coluber constrictor foxii

Elapidae:

Distribution: Southern North America to southern South America, Africa, southern Asia to southern Australia, and the tropical Indian and Pacific Oceans.

Characteristics and biology: Venomous snakes; proteroglyphous.

Subfamily: Elapinae

Number of genera: 17

Characteristics and biology: Predominately terrestrial; Mostly oviparous.

Hydrophiinae. Note the paddle-like tail on the left.

Subfamily: Hydrophiinae

Number of genera: 43

Characteristics and biology: Terrestrial and aquatic; sea snakes have paddle-like tail; all sea snakes are viviparous, birth occurs in water; sea kraits are oviparous. 

Viperidae:

Distribution: Wordwide, except Papuaustralia and oceanic islands

Characteristics and biology: Venomous; Solenoglyphous; Most have robust bodies and triangular heads. 

Subfamily: Viperinae

Number of genera: 13

Characteristics and biology: Lack loreal pits; most are terrestrial. 

Subfamily: Crotalinae

Number of genera: 26

Characteristics and biology: Well developed loreal pit for infrared receptors; Most are viviparous.

Ohio species:

*Agkistrodon contortrix mokasan (Northern Copperhead: Mokasan)

*Sistrurus catenatus catenatus (Eastern Massassauga)

*Crotalus horridus (Timber Rattlesnake) 

Representatives of Crotalinae (L to R): Sistrurus catenatus catenatus, Agkistrodon contortrix contortrix, Crotalis horridus

Until next time...at the zoo!

MH & KG

Blog Entry 6: Serpentes/Ophidia: Brad and Michele

Serpentes/Ophidia: Brad and Michele

Location: John Carroll University Ecology Lab
Time: March 1 & 16th 2012, 1:30pm
Objective: Identify and recognize the diversity of Serpentes (Ophidia)

Background:
Serpentes is a highly diverse clade that is broken up into 16-23 families (based on whom you reference). Some of the main families that we focused on include representatives from: Pythonidae, Boidae, Colubridae, Elapidae, and Viperidae. Some of the synapomorphies that define these groups overall include: fused premaxillae, fused parietals, reduced nasals, lack of vomerine teeth, specialized joints between ulna-ulnare and radius-radiale, specialized ankle joints, well developed hemipenes, saccular ovaries, Jacobson’s organ (vomeronasal organ) separated from nasal capsule, lacrimal duct joining the vomeronasal duct, femoral and pre-anal glands, and egg tooth at hatching.

While much of the lab was focused on the diversity, we began with learning some of the basic anatomy, articulation and kinesis of the skull.

Snakes are significantly different from lizards for many reasons, with one of the main reasons being the presence of extreme cranial kinesis and streptostyly (where the quadrate can dislocate from the lower jaw to facilitate the wide opening of the mouth). There are approximately six points of articulation in a typical snake skull:

1. Lower jaw and Quadrate
2. Quadrate and Supratemporal
3. Supratemporal and Parietal
4. Dentary and Compound bone
5. Prefrontal and Maxilla
6. Frontal and Nasal

Below are pictures of skulls with the bones labled and points of articulation labeled on the Proteroglyphous skull.

Another point of anatomy that we focused on was the dentition, with specific focus on the teeth and fang arrangements. Overall, there are four major teeth and fang categories:

1. Aglyphous – These types of teeth do not have grooves and are conical, “typical” teeth found in all species of snakes.

Lampropeltis getula californiae putting those Aglyphous teeth to work!

2. Opisthoglyphous – rear-fanged teeth with a groove, aiding in venom injection - Found in Colubridae

Heterodon nasicus (Hognose snake) skull

3. Proteroglyphous – hollow, front-fanged teeth with relatively static movement on a small maxilla - Generally found in Elapidae

Cobra skull with points of articulation circled.

4. Solenoglyphous – hollow, retractable/protractable fangs positioned on a kinetic maxilla. These are the most derived teeth which allow for deep injection - Generally found in Viperidae

Rattlesnake skull

The second main portion of the lab focused on observing some specific key families among the Serpentes in both Henophidia (“old” snakes) and Caenophidia (“new” snakes).

Family:
Boidae:Distribution: W. North America – Subtropical S. America, West Indies, Central Africa, S. Asia, Madagascar, S.W. Pacific islands
Characteristics: Cranial infrared receptors in interlabial pits, hindlimb vestiges-cloacal spurs, pelvic remnants, non-venemous, aglyphous
Subfamily:
Boinae:
Genera: 7
Distribution: Tropical Americas, W. Indies, Madagascar, S.W. Pacific
Characteristics: Labial sensory pits occur, mostly arboreal

Erycinae:
Genera: 4
Distribution: W. North America, Central Africa, Asia, W. China
Characteristics: Labial sensory pits absent, semi-fossorial.

Pythonidae: Pythons
Genera: 8
Distribution: Sub-Saharan Africa, S. and S.E. Asia-Australia
Characteristics: non-venemous, vestigial spurs, constrictors, labial pits set in scales, aglyphous

Colubridae: Colubrids
Distribution: Worldwide
Characteristics: Most structurally diverse group (show all fang types), NO cranial infrared receptors occur in pits or surface indentations, girdle elements absent externally and internally.
Colubrinae:
Genera: more than 100
Distribution: Worldwide
Characteristics: Highly diverse biology and ecology (family characteristics)

Lampropeltis triangulum

Dipsadinae:
Genera: more than 90
Distribution: Americas
Characteristics: Terrestrial, primarily oviparous, venomous (but not usually harmful to humans), Opisthoglyphous

Lower snake: Carphophis amoenus

Natricinae:
Genera: 38
Distribution: N. America, Africa, Eurasia, E. Indies.
Characteristics: Mainly aquatic species, fish and amphibian specialists

Elapidae: Cobras, Kraits, Sea Snakes, Death Adders and Allies
Genera: more than 100
Distribution: S. North America – S. South America, Africa, S. Asia, India, Pacific oceansCharacteristics: venomous, no cranial infrared receptors, proteroglyphous

Hydrophiinae:
Genera: 43
Distribution: S. North America – S. South America, Africa, S. Asia, India, Pacific oceans
Characteristics: Laterally compressed, paddle tail, loss of enlarged ventral scales (photo below), viviparous , terrestrial and aquatic taxa.

Elapinae:
Genera: 17
Distribution: Americas, Africa, Eurasia, E. Indies, Phillipines
Characteristics: Ophiophagus (eat snakes), fossoreal species are aposematic, arboreal, aquatic, but mostly terrestrial, and mostly oviparous.

Viperidae: Vipers and Pit Vipers
Distribution: Worldwide, except Papuaustralia and oceanic islands.
Characteristics: venomous, solenoglyphous
Azemiopinae:
Genera: 1
Distribution: South and Central China, Burma, and Vietnam
Characteristics: Lack a loreal pit, semi-fossoreal, may dehydrate rapidly in dry environments
Crotalinae:
Genera: 26
Distribution: S.W. and S. Asia and the Americas
Characteristics: Well developed loreal pit for infrared receptors, most viviparous, some oviparous (more basal), rattles present except in basal species.

Viperinae:
Genera: 13
Distribution: Africa, Europe, and Asia
Characteristics: Lack loreal pits, oviparous and viviparous taxa, don’t exceed greater than 2m, terrestrial

Ohio species to know:

Colubridae:
Natricinae

• Nerodia sipedon sipedon (Northern Water Snake)
• N. s. pleuralis (Midland Water Snake)
• N. erythrogaster neglecta (Copperbelly Water Snake)
• Regina septemvittata (Queen Snake)
• Thamnophis butleri (Butler’s Garter Snake)
• Thamnophis sirtalis sirtalis (Eastern Garter Snake)
• T. radix radix (Eastern Plains Garter Snake)
• T. sauritus sauritus (Eastern Ribbon Snake)
• T. sauritus septentrionalis (Northern Ribbon Snake)
• Storeria dekayi wrightorum (Midland Brown Snake)
• S. dekayi dekayi (Northern Brown Snake)
• S. occipitomaculata occipitomaculata (Northern Redbelly Snake)
• Virginia valeriae valeriae (Eastern Smooth Earth Snake)

Dipsadinae

• Diadophis punctatus edwardsi (Northern Ringneck Snake)
• Heterodon platyrhinos (Eastern Hognose Snake)
• Carphophis amoenus amoenus (Eastern Worm Snake)
• C. a. helenae (Midwest Worm Snake)

Colubrinae

• Opheodrys vernalis (Smooth Green Snake): much of state
• O. aestivus (Rough Green Snake): southern third of state
• Coluber constrictor foxii (Blue Racer)
• C. c. constrictor (Northern Black Racer)
• Pantherophis obsoletus obsoletus (Black Rat Snake)
• P. vulpina (Fox Snake)
• Lampropeltis triangulum triangulum (Eastern Milk Snake)
• L. getula nigra (Black Kingsnake): southern part of state

Viperidae:
Crotalinae

• Agkistrodon contortrix mokasan (Northern Copperhead: Mokasan)
• Sistrurus catenatus catenatus (Eastern Massassauga)
  
• Crotalus horridus (Timber Rattlesnake)