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Questions? common tree snake, Dendrelaphis punctulatus (Australia) Integrating Conservation in Agriculture EFB 496 (2 credits) The Roosevelt Wild Life Station is offering an intensive spring break field course on conservation in agricultural landscapes to seniors of any major. Space for 10 students is available. Selection will be highly competitive. Students will advise landowners on how to improve the biodiversity value of their property and suggest ways to enhance beneficial interactions between wild species and agricultural production. Topics covered in this course will include: - ecological monitoring - biodiversity survey techniques - invasive species management - sustainable harvest and marketing of native species - the economics of conservation - a wide array of ecologically-conscientious land management and farming techniques Students MUST be available on the following dates to participate: February 5: Introductory lunch with landowners (1 pm – 3pm) March 11-19: Spring break field trip to study sites May 11: Thank you dinner with landowners (time TBA) *Students will also meet regularly at a TBA time before and after the spring break trip. Contact Sam Quinn to apply ([email protected]; Illick 254). Deadline Jan 20 to apply. Herps Field Course: Peru Learn about the natural history, anatomy, ecology, and conservation of Neotropical reptiles and amphibians while staying at an active research field station in Peru. This course will give participants advanced training in field techniques relevant to tropical biology research, with special emphasis on field exercises over classroom-based lectures. Students will use drift fence and leaf litter sampling, make audio recordings, conduct transects, and much more. We will also read and discuss selected literature on tropical ecology, applied research, and conservation issues pertinent to the the Madre de Dios region of Peru and beyond. COURSE DATES May 25th – June 7th, 2017 REGISTRATION Course size is limited, spots are filled on a rolling basis until April 17th, 2017 COURSE FEE $2100 (includes all meals and lodging at the field station, as well as transportation from Puerto Maldonado to the field site and back) MORE INFORMATION https://fieldprojects.org/participate/courses-2/field-herpetology LOCATION This course will be held at the Los Amigos Biological Station, situated between the Madre de Dios and Los Amigos Rivers on terra firme forest rising above the floodplain. This field station lies within the buffer zone of Manu National Park, which was recently declared the world’s top biodiversity hotspot, due in no small part to having the largest number of amphibian and reptile species on the planet. Origins of tetrapods = origins of the amphibians Origins and evolution of the major extant groups… Outline of today’s lecture Brief (very) introduction to phylogenetic analyses Origin of tetrapods Origin of amphibians The three major amphibian clades Current Linnaean Classification Evolutionarily speaking, “herpetiles” are a somewhat unnatural grouping of rather different animals Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Agnatha: Fish lacking jaws Class Chondrichthyes: Cartilaginous fish Class Osteichthyes: Bony fish Class Amphibia Class Reptilia Class Aves Class Mammalia Fishes Phylogentic systematics (see Ch. 2) Phylogenetic systematics (cladistics) emphasizes the importance of evolutionary relationships Shared derived characters (synapomorphies) are used to identify clades and infer the order in which they branched Parsimony is an assumption built into phylogenetic models (assumes simplest possible path). “Occam’s Razor” Phylogentic systematics (see Ch. 1) A monophyletic lineage (clade) is composed of an ancestor and all of its descendants. Only monophyletic lineages are recognized in phylogenetic systematics A polyphyletic group consists of distantly related taxa whose last common ancestor is not a member of the group A paraphyletic group includes all of the descendants of a common ancestor minus one or more monophyletic groups Polyphyletic group Polyphyletic group Reptilia is a paraphyletic group if birds are excluded “non-avian reptiles” Last terminology: Amphibia and Mammalia are sister groups. They are adjacent branches on the cladogram Mammalia is an outgroup to Reptilia. It is outside of the reptile clade. Where did amphibians (and all vertebrate tetrapods) arise? The Devonian opportunity The Devonian opportunity Late Devonian ~ 375 MYA, a diversity of shallow aquatic habitats developed (warm, no glaciers) This generated a variety of unexploited microhabitats Detritus from terrestrial and wetlands vegetation provided a base for increasingly complex food webs Exploitation of these new habitats was driving force behind the evolution of the tetrapods Refinements and variations of the adaptations that enabled tetrapods to use these new habitats enabled them to expand onto the land Tiktaalik Why lobe-finned fish? Free-swimming predators of shallow waters and adapted to living on the water’s edge. Likely had “preadaptations” for terrestrial life Limb-like structures (paired, lobed fins) used for stalking prey in shoreline vegetation May have used fins to prop up and respire in shallow stagnant pools How do we know tetrapods are descended from lobe-finned fish? labyrinthodont teeth = maze or labyrinth pattern of tooth surface. This character is not shared with other fishes Icthyostega is a “stem tetrapod” basically a fish with legs What transitions to terrestriality were required? Or How do you get from fish to tetrapod? Or “Exaptations” Respiration Air breathing: Lungs were already present in many bony fishes (e.g. the Dipnoi or lungfish) Coping with anoxic waters A passive pump mechanism (gulping and diving head-first) was replaced with a buccal-force pump (mouth opens, floor drops, mouth closes, floor raised, air forced into lungs) Morphology Fins to limbs — joints formed in “legs” and digits formed from fin rays Support system changed — no longer supported by buoyancy in water (density water = 1 g/cm3; air = 0.001 g/cm3) Vertebral column and limb girdles become more robust. Feeding Suction feeding no longer possible Skull and vertebral column become mobile Elongated jaws develop Other changes… A rudimentary ear develops from vestigial fish jaw bones Nasal passages develop for respiration and olfaction Skin thickens to protect from desiccation and abrasion The origin of modern amphibians “The origin of lissamphibians has been hotly debated in the last few years, and the number of hypotheses about their origin has not decreased despite several detailed phylogenetic analyses.” Marjanovic and Laurin 2007 Confusion: soft-bodied , do not preserve well ? Recent perspective: A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature 453, 515-518 (22 May 2008) Primitive amphibians: Lepospondyls Labyrinthodont teeth Simple, spool-shaped vertebrae; bony cylinders around the notochord Diverse body forms (e.g. some with limbs others without) Generally small (a few cm - 1m) Held niches of modern salamanders, caecilians, and lizards Primitive amphibians: Temnospondyls Labyrinthodont teeth Resemble large salamanders, crocodiles Complex vertebrae consist several separate elements Size ranges from 20 cm – 3 m Numerous sharp, conical, teeth, and the large fangs suggest that they were predators Siderops Temnospondyls and lepospondyls of the Late Paleozoic Monophyletic within the temnospondyls? Rhipidistian crossopterygian lobe-finned fish Lepospondyls Temnospondyls Gymnophiona Anura Caudata Monophyletic within lepospondyls? Rhipidistian crossopterygian lobe-finned fish Lepospondyls Temnospondyls Gymnophiona Anura Caudata Diphyletic (two separate ancestries) with caecilians within the lepospondyls and salamanders and frogs within the temnospondyls? Rhipidistian crossopterygian lobe-finned fish Lepospondyls Temnospondyls Gymnophiona Anura Caudata Figure 2.9 Three hypotheses for the origins of modern amphibians A phylogenetic expression of previous points Carboniferous: Age of Giant Amphibians Increasingly warm, with moist terrestrial environments Highly favorable environments for amphibians 360 to 286 MYA Gerobatrachus (early Permian, ~290 MYA) The earliest fossil that can be clearly assigned to an extant lissamphibian clade “frogamander” discovered in Texas Triadobatrachus (early Triassic, 245 MYA) Sister taxon to Anura (frogs and toads) “Protofrog” discovered in Madagascar Slow subsequent radiations These early amphibians radiated later in the Cretaceous and Paleocene (50-150 MYA) to generate many of the extant amphibian families. Many extant amphibian families are essentially unchanged for epochs Pipidae, Pelobatidae = 150 million years! local red-spotted newt genus (Notophthalmus) unchanged for 20 million years! Extant amphibian diversity Pyron & Wiens (2013) Large-scale phylogenetic analyses reveal the causes of high tropical amphibian diversity. Proc R Soc B 280: 20131622. Subclass Lissamphibia – living amphibians (two other subclasses now extinct) Liss = smooth (refers to smooth scaleless skin) Amphi = double Bios = life Extant amphibians fall into one of three orders – Anura (frogs, including toads) Caudata or Urodela (salamanders, including newts) Gymnophiona or Apoda (the limbless caecilians) Traits of the Lissamphibia Smooth skin Especially in larvae – 2-3 layers Site of gas exchange Permeable to water Contains poison glands (granular), pheromone glands (hedonic glands), and mucous glands Traits of the Lissamphibia Therefore, need high levels of humidity or a fully aquatic environment to live (some exceptions) Reason for nocturnality, precipitation association, seasonality Traits of the Lissamphibia Shell-less eggs Traits of the Lissamphibia Generally eggs laid in water, hatch into larvae, and metamorphose into a morphologically distinct adult form. Australian gastric brooding frog Traits of the Lissamphibia Three-chambered heart with two atria and one ventricle atria ventricle Pedicellate teeth (crown of teeth is separated from the root by a zone of fibrous tissue) Ability to elevate the eye (with levetator bulbi muscle) Operculum • small bone in the skull • linked to shoulder girdle by the opercularis muscle • Hearing? Balance? • Fused to the columella (ear bone, stapes) in most anurans) • Not in caecilians, some salamanders To here! Thurs Lab Relocated: To 220 Illick from 238 Much nicer Bigger More convenient 220 is just up the hall from 238, same side (Fri lab stays as is in 238 Illick) ESF Herpetology Club! Order Anura – frogs and toads or “tail-less amphibians” ~6,000 species Size range considerable… West African goliath frog, Conraua goliath Tiny frog claimed as world's smallest vertebrate Paedophryne amauensis (Sumatra) Frog or toad? Bufo bufo - common toad Rana temporaria - common frog Atelopus zeteki - Panamanian golden “frog” Anuran traits Fore- and hind-limbs usually of unequal size - hind limbs are elongated and modified for jumping Tail in larval form lost as adult Figure 1.3 Anuran body forms Anuran skeleton Head and trunk fused Fused radius and ulna Urostyle Fused tibia and fibula Anurans typically have external fertilization and lay eggs… …but there is a wide diversity of reproductive modes among anurans Ancestral mode Tadpoles Many are herbivorous, omnivorous “basically a swimming sieve attached to a gut” Origins Photo: Eiko Jones High rates of predation Typically less than 10% of tadpoles reach metamorphosis Highly unusual in rapid transformation from prey to predator (e.g., with Odonates) Transition away from water Parental care usually none but sometimes Direct development Egyptian mythology In Egypt the frog was associated with Heket, the goddess of fertility and childbirth Frog shaped knives placed on the bellies of pregnant women and newborn babies were believed to protect the children "Double, double, toil and trouble, fire burn and cauldron bubble - fillet of fennel, snake, toad, adder's fork, lizard's leg..." Macbeth Toads in potions and spellcraft Toads as witch’s “familiars” Witches concocted brews from frogs, toads and snakes, often referred to as “Toad Soup” Secrete a thick, white substance (bufotenine/bufotoxin) from skin glands when provoked (toxic and hallucinogenic components) The toxin (C24H34O5) is called bufagin, or more colloquially, toads' milk Toad licking “Profound alteration of consciousness within a few seconds of exhaling. I relax into a deep, peaceful interior awareness. There is nothing scary about the effects and no sense of toxicity. I try to describe my feeling but am unable to talk for the first five minutes and then only with some difficulty. This is a powerful psychoactive drug, one that I think would appeal to most people who like the effects of hallucinogens. For the next hour I feel slow and velvety, with a slight pressure in my head. No long-lasting effects to report.” (A.T. Weil) Weil AT, Davis W (1994) Bufo alvarius: a potent hallucinogen of animal origin. Journal of Ethnopharmacology 41:1-8 Bufotenine (5-OH-DMT) is Schedule I in the United States. This means it is illegal to manufacture, buy, possess, or distribute (sell, trade or give) without a DEA license. Not available by prescription. Toad Stones Sweet are the uses of adversity, Which, like the toad, ugly and venomous, Wears yet a precious jewel in his head; And this our life, exempt from human haunt, Finds tongues in trees, books in the running brooks, Sermons in stones, and good in everything. William Shakespeare, As You Like It (Duke Senior at II, i) If swallowed, it was a certain antidote against poison Order Caudata (or Urodela) newts and salamanders “bearing a tail” ~650 species Figure 1.2 Salamanders occupy aquatic, terrestrial, and arboreal habitats All are “salamanders” Size range considerable… dwarf salamander (Nototriton sp.), Costa Rica Chinese giant salamander (Andrias davidianus) Newt or salamander? But newts are in the family Salamandridae … so are ‘true salamanders’! Generally, salamanders lacking costal grooves with rough / drier skins are referred to as newts New discoveries 2016-2017 Crocodile newts (Vietnam) Luristan newt (4 streams, n Iran) Traits of Caudates Have four limbs usually of equal size (with the exception of sirens), a tail, and elongated body Generally fossorial (live in soil or leaf litter) or aquatic The most prolific group (Plethodontidae) is lungless — • Skin is a site of gas exchange • Use hyoid apparatus to project tongue and capture prey Fertilization is internal Aquatic and terrestrial eggs Larvae are stream-lined and carnivorous Paedomorphosis is common In paedomorphosis is a form of heterochrony, where adults are aquatic and retain traits of juveniles obligate facultative Proteus Necturus Ambystoma tigrinum Salamanders “Salamander” is derived from an Arab-Persian word which means “lives in fire” Why? immune to fire, and could extinguish fire with skin secretions? Skins, bodies, and body parts of salamanders still used in traditional medicine. Torched newts are sometimes sold in Asia as aphrodisiacs. A “salamander”… Order Gymnophiona (or Apoda) caecilians: ~200 species restricted to the tropics caecilian, Muquinqui, north Sao Tome Pronunciation of caecilian “Sicilian” “Say-cilian” Greek words γυμνος (gymnos, naked) and οφις (ophis, snake) Latin word caecus, meaning "blind", referring to the small or sometimes nonexistent eyes Figure 1.4 Caecilians are elongate, legless amphibians Characteristics “without legs” = apoda subterranean diggers eyes may be covered by skin or even bone tentacle of head serves as a chemosensory organ to detect underground prey encircling primary grooves = annuli, with dermal (bony) scales often lie deep within the tissues of each annular groove Caecilian reproduction Internal fertilization Viviparity common – young 30-60% of female’s body size when born Initial growth of fetuses supported by yolk sac, embryos feed on uterine milk secreted from the epithelial wall of oviduct Obscure, uncommon and poorly studied Not much interaction, not much folklore, except… Origins of tetrapods and amphibians End…