Pan-Osteichythyes Flashcards
Original of Teeth
Gnathostome synapomorphies, derived feeding mechanism, controversial origin
Components of odontode
Denting core, enamel cap, secured to a ‘bone of attachment’
Teeth - Basic Distinctions
Marginal, Palatal, and Pharyngeal Teeth
Character of Marginal Teeth
Teeth along jaw margin like PTQ, MC or maxilla/dentary
Characteristics of Palatal Teeth
Root in oral cavity
Not common in gnathys
Characteristics of Pharyngeal Teeth
Role of endoderm?
Teeth along gills?
- 1st arch is where teeth originate
Polyphyodont vs Diphyodont
Poly: continual replacement, plesiomorphic condition
Di: one set of replacement, two sets of teeth
Gnathostome Stem
-Bone; aspirin; dentin - enameloid exoskeleton
Pterspidomorphs
-stomach (diversified gastro-intestinal tract)
Anaspida & Thelodonts
-hypophysis opens into oral cavity
-paired nasal capsules
-endochondral ossification
Galaespids
-perichondral ossification
-cellular dermal bone
-epidermal tail
-sclera ring
-paired, pectoral appendages
Osteostracans
-JAWS
“Placoderms”
Gnathostome
What are Ostracoderm?
General term describing stem Gnathostome that were jawless armored fish, but is now broadly paraphyletic
What are Placoderms
Stem gnathostomes with jaws
- Brindabellaspids
- Antarchs
Even more Gnathostome Synapomorphies (Ear Section)
3 Semicircular Canals in the Vestibular Component of Inner Ear
- In placoderms, the bony features were considered osteichthyan, but is now gnathostome characters since CHondrichtyes lost bone, so it’s a derived condition
Crown Osteichthyes (435 is defined by he split between
Actinopterygia (ray finned) and Sarcopterygia (lobe finned)
What happens along the stem between Gnathostomata and osteichthyes?
-increasing complex opercular, dynamic pharynx, air bladder as paired diverticulum of foregut (lung!)
**REDUNDANCY: gill and lungs for breathing; pathway to specialization
Sarcopterygian Synapomorphies
-Lobe fins
-Cranial Fissure
- Reduced opercular/gular series
What are lobe fins?
A Sarcopterygian synapomorphies part of the proximal skeleton of LPM.
-Isn’t used by Actinisia for propulsion
- Stabilizing and steering (autapomorphic?)
What is the cranial fissure?
Intracranial joints
Basically facilitates the kinetic skull
- wider gape
What is meant by reduced opercular/gular series?
Sacropterygian synapomorphy where there is a reduction of bones covering the gills and throat
Information about Pan-Actinisia’s apomorphies?
Crown inside Sarcopterygian and its autapomorphies include crazy growth trajectories of neurocranium/brains
- fat filled
- notochord enlargement
Crown Choanata (413) is defined by the split between
Dipnoi and Tetrapoda
Crown Sarcopterygia is defined by the split between
Choanata and Actinistia
Crown Dipnoi
- 6 extant species
- carnivorous
- shallow water
- highly derived teeth
- retain gills
- single, dorsal lung
What are choanae?
interna; nares, basically nasal openings
Differences in choanae between Sarcopterygia and choanates?
Sarcoprtyergia
- plesiomorphic
– anterior and posterior nasal openings (both external)
– nasal cavity + olfaction separated from breathing
Derived condition for choanates
- Posterior openings = internal (choanae)
- links olfaction to breathing and feeding
- -nasal cavity connected to pharynx
