INTEGBI 175LF Lecture Notes - Lecture 14: Geoemydidae, Macrochelys, Interclavicle
14 May 2018
School
Department
Course
Professor
Lecture 14: TURTLES
●350 sp, 14 families
●Cosmopolitan dist besides high altitudes
●Characteristics:
○Variable limb structure
○omnivores/herbivores
○Usually have elaborate courtship
○Single, median penis
○Oviparous
○No parental care
○Shell:
■Carapace : dorsal
●Neural, nuchal, pygal, pleural (ribs), peripheral
■Plastron : ventral
●Epiplastron ( clavicle ), entoplastron ( interclavicle ), hyoplastron,
hypoplastron, xiphiplastron
■Bridge : connects carapace and plastron
■Pect and pelvic girdle internal to rib cage → req extensive repatterning
■Pattern of scutes and underlying bones not matching → thought to provide more
structural integrity
■Limits niche diversity
■May have hinged shells
■Lungs : attached to carapace and viscera
○Adductor mandibulae : powerful jaw adduction
■Middle ear expanded → not as much room for adductor
■Skulls lack fenestrae , but are emarginated → creates room for muscles, but
posterior position creates mech disadvantage
■Trochlear cartilage : acts as a pulley, evolved independently in pleuro and
cryptodires
●On pterygoid in pleurodires
●On quadrate in cryptodires
○Sex determination:
■TSD :
●Most common
●1a : higher T → F
●1b : higher T → M
●II : intermediate → M (macrochelys)
■GSD : males or females heterogametic, Geoemydidae has both
■Testosterone : thought to be gomad diferentiating hormone
■Aromatase : converts testosterone → estradiol, creates + feedback loop w/ ovaries
■5-A reductase : produced at temps for males, converts testosterone →
dihydrotestosterone that binds to receptors on testes, creates + feedback loop
●Fossil record:
Document Summary
Epiplast(cid:418)on (cid:1827) (cid:283)la(cid:475)i(cid:283)le (cid:1828), entoplast(cid:418)on (cid:1827) inte(cid:418)(cid:283)la(cid:475)i(cid:283)le (cid:1828), h(cid:482)oplast(cid:418)on, h(cid:482)poplast(cid:418)on, (cid:481)iphiplast(cid:418)on. Pe(cid:283)t and pel(cid:475)i(cid:283) (cid:322)i(cid:418)dle inte(cid:418)nal to (cid:418)i(cid:282) (cid:283)a(cid:322)e (cid:418)e(cid:417) e(cid:481)tensi(cid:475)e (cid:418)epatte(cid:418)nin(cid:322) Patte(cid:418)n o(cid:321) s(cid:283)utes and unde(cid:418)l(cid:482)in(cid:322) (cid:282)ones not mat(cid:283)hin(cid:322) thou(cid:322)ht to p(cid:418)o(cid:475)ide mo(cid:418)e st(cid:418)u(cid:283)tu(cid:418)al inte(cid:322)(cid:418)it(cid:482) Lun(cid:322)s : atta(cid:283)hed to (cid:283)a(cid:418)apa(cid:283)e and (cid:475)is(cid:283)e(cid:418)a. Middle ea(cid:418) e(cid:481)panded not as mu(cid:283)h (cid:418)oom (cid:321)o(cid:418) addu(cid:283)to(cid:418) Skulls la(cid:283)k (cid:321)enest(cid:418)ae , (cid:282)ut a(cid:418)e ema(cid:418)(cid:322)inated (cid:283)(cid:418)eates (cid:418)oom (cid:321)o(cid:418) mus(cid:283)les, (cid:282)ut poste(cid:418)io(cid:418) position (cid:283)(cid:418)eates me(cid:283)h disad(cid:475)anta(cid:322)e. T(cid:418)o(cid:283)hlea(cid:418) (cid:283)a(cid:418)tila(cid:322)e : a(cid:283)ts as a pulle(cid:482), e(cid:475)ol(cid:475)ed independentl(cid:482) in pleu(cid:418)o and (cid:283)(cid:418)(cid:482)ptodi(cid:418)es. Gsd : males o(cid:418) (cid:321)emales hete(cid:418)o(cid:322)ameti(cid:283), geoem(cid:482)didae has (cid:282)oth. Testoste(cid:418)one : thou(cid:322)ht to (cid:282)e (cid:322)omad di(cid:498)(cid:321)e(cid:418)entiatin(cid:322) ho(cid:418)mone. A(cid:418)omatase : (cid:283)on(cid:475)e(cid:418)ts testoste(cid:418)one est(cid:418)adiol, (cid:283)(cid:418)eates + (cid:321)eed(cid:282)a(cid:283)k loop (cid:476)/ o(cid:475)a(cid:418)ies. 5-a (cid:418)edu(cid:283)tase : p(cid:418)odu(cid:283)ed at temps (cid:321)o(cid:418) males, (cid:283)on(cid:475)e(cid:418)ts testoste(cid:418)one dih(cid:482)d(cid:418)otestoste(cid:418)one that (cid:282)inds to (cid:418)e(cid:283)epto(cid:418)s on testes, (cid:283)(cid:418)eates + (cid:321)eed(cid:282)a(cid:283)k loop. Ea(cid:418)l(cid:482) (cid:321)ossils la(cid:283)k head (cid:418)et(cid:418)a(cid:283)tion (cid:283)on(cid:475)e(cid:418)(cid:322)ent e(cid:475)olution. Pappochelys rosinae : oldest stem tu(cid:418)tle, mid t(cid:418)iassi(cid:283) (cid:1827)(cid:1681)(cid:1683)(cid:1679) m(cid:482)a(cid:1828), (cid:418)etained diapsid skull.
