The Biology of Amphibians Agnes Scott College Mark Mandica Executive Director The Amphibian Foundation [email protected] 678 379 TOAD (8623) Cryptobranchidae: Cryptobranchus alleganiensis 3.1: Salamander Biology Ambystomatidae: Ambystoma tigrinum salamanders posses tails in larval and adult forms most have limbs of equal size Salamandridae: Taricha rivularis anatomy Plethodontidae: Plethodon cinereus eye socket hindlimb rib hyoid tail forelimb vertebrae sacral vertebrae (1) Cryptobranchidae: Andrias japonicus skeletal anatomy m = maxilla n = nasal pm = pre-max sph = sphenethmoid f-p = frontoparietal pro = prootic sq = squamosal eo = exoccipital q = quadrate qj = quadrato-jugal pt = pterygoid pal = palatine ps = parasphenoid sta = stapes skeletal anatomy Proteidae: Necturus maculosus skeletal anatomy Sirenidae: Siren lacertina skeletal anatomy Ambystomatidae: Ambystoma tigrinum skeletal anatomy hyoid apparatus An arrangement of bones and cartilage in the floor of the mouth and throat. Cryptobranchidae: Andrias japonicus skeletal anatomy ‘Hellbender’ exhibiting suction feeding by depressing the hyoid apparatus Cryptobranchidae: Cryptobranchus alleganiensis Functional morphology Reproduction Salamander Life Cycle Sexual dimorphism in the cloaca of adult salamanders SALAMANDER REPRODUCTION FEMALES PICK UP THE SPERMATOPHORE AND FERTILIZE THE EGGS SPERMATOPHORES THIS ONE HAS BEEN PICKED UP BY A FEMALE SALAMANDER REPRODUCTION EGGS ARE LAID IN WATER OR ON LAND DEPENDING ON THE SPECIES Ambystomatidae: Ambystoma maculatum Plethodontidae: Eurycea cirrigera Ambystomatidae: Ambystoma maculatum SALAMANDER LARVAE PAEDOMORPHOSIS RETENTION OF JUVENILE CHARACTERISTICS IN THE ADULT FORM MANY SALAMANDER SPECIES ARE PAEDOMORPHIC AND DO NOT METAMORPHOSE FULLY (OBLIGATE). OTHER SPECIES, LIKE TIGER SALAMANDERS, CAN BE PAEDOMORPHIC IF THE SITUATION IS SUITABLE AND THEN METAMORPHOSE LATER IF NECESSARY (FACULTATIVE) THIS IS AN ADULT MUDPUPPY (NECTURUS MACULATUS) EVEN THOUGH IT HAS JUVENILE SALAMANDER CHARACTERS LIKE AQUATIC (FLAT) TAIL AND LARGE EXTERNAL GILLS. THIS ANIMAL CEASED DEVELOPING PHYSIOLOGICALLY (SOMATICALLY) BUT CONTINUED TO DEVELOP SEXUALLY. THIS PROCESS IS CALLED NEOTENY. IN TYPICAL DEVELOPMENT, AGING AND MATURITY ARE SYNCHRONIZED. IN PAEDOMORPHOSIS, THE TWO PROCESSES BECOME SEPARATED. THIS PHENOMENON IS CALLED HETEROCHRONY. Paedomorphosis The result from either neoteny or progenesis PAEDOMORPHOSIS RETENTION OF JUVENILE CHARACTERISTICS IN THE ADULT FORM THIS IS AN ADULT MOLE SALAMANDER (AMBYSTOMA TALPOIDEUM) EVEN THOUGH IT HAS JUVENILE SALAMANDER CHARACTERS LIKE AQUATIC (FLAT) TAIL AND LARGE EXTERNAL GILLS. THIS ANIMAL REACHED SEXUAL MATURITY AT A MUCH EARLIER AGE THAN MOST MOLE SALAMANDERS, WHILE STILL IN LARVAL FORM. THIS PROCESS IS CALLED PROGENESIS. PAEDOMORPHOSIS RETENTION OF JUVENILE CHARACTERISTICS IN THE ADULT FORM THIS IS AN ADULT (LEUCISTIC) AXOLOTL (AMBYSTOMA MEXICANUM) EVEN THOUGH IT HAS JUVENILE SALAMANDER CHARACTERS LIKE AQUATIC (FLAT) TAIL AND LARGE EXTERNAL GILLS. Regeneration Limb Regeneration Has been well documented in Axolotls and Firebelly Newts Ambystomatidae: Ambystoma mexicanum Salamandridae: Cynops sp. Stages of Limb Regeneration Salamandridae: Cynops sp. .