Euarchontoglires Flashcards
(34 cards)
Euarchotnoglires consists of
Archonta- Dermoptera, Scadentia and Primates
Glires- Rodents
Previously thought to contain bats
Dermoptera
Colugos, SE Asia
Cynocephalus volans and Galeopterus variegatus
Dermopteran characters
patagium (connects neck-wrist-hindlimb-tail), allows gliding
folivorous
comb-like lower incisors (with individual tines) - similar to those of fossil Antilohyrax- good for stripping fleshy parts off plants
In colugos, also used to comb hair (see evidence of hair stuck in teeth, and hair-shaped wear)
anterior upper cheek teeth reduced
nearly complete post-orbital bar
Scadentia
Tree shrews, SE Asia 5 genera: Tupaia Ptilocerus Dendrogale Anathana Urogale
historically regarded as part of primates, but currently very hard to place, no one really knows where they are
some genomic data place as rodent sister, but mRNAs place as most basal primate
Scadentian characters
post orbital bar
procumbent, elongate, comb-like incisors (each tooth has individual tine unlike in dermoptera, much more similar to lemuriform primates, however no evidence of use in social grooming)
w- shaped, dilambdodont upper molars
no hypocone cusp
bony tubes enclosing middle ear arteries
ecto/endotympanic bulla
Primate dichotomy
Haplorhini (tarsiers, monkeys, apes)
Strepsirrhini (Malagasy primates (lemurs, indrids, sifakas, aye-aye), plus galagos and lorises)
Strepsirrhini
limited to Madagascar, Africa, SE Asia
lorises, pottos and bush babies in Africa and Asia, nocturnal insect hunters
lemurs, sifakas, aye-ayes and indrids on Madagascar
aye-aye, only living strepsirrhine that doesn’t have tooth comb
uses rodent-like incisiors and elongate digits- fills woodpecker niche
Strepsirrhine fossils
Palaeopropithecus - sloth-like
Archaoelemur - koala-like
Megaladapsis - largest ever
all Malagasy strepsirrhines have derived from 1 common ancestors and diversified because no other diverse groups eg. bovids present
Strepsirrhine characters
only archontan dental comb that is made of separate teeth that is actually used for grooming- for social grooming, and can be for feeding eg. Euoticus
post-orbital bar
grooming claw on pedal digit II
sloping lateral fibular facet on astragalus
external continuity of rhinarium with mouth (‘wet’ nose)=> allows contact with vomeronasal organ (paired sense organ at floor of anterior nasal fossa, relevant for intraspecific male-female interactions- pheromone detectors)
same function as horse flehmen response and cat palatine papilla
Haplorrhine characters
‘dry’ nose, no connection
VNO embryonically present in all, but degenerates in some adult species
VNO present in platyrrhines (new world monkeys) and tarsiers, but absent in catarrhines
Many catarrhines rely more heavily on trichromatic vision
Most platyrrhines have VNO and dichromatic
Tarsiidae
Tarsiers
wet forests of Phillipines, Borneo, Sumatra, Indonesian archipelago
nocturnal, insect-eating- niche closer to galago than monkey
grade Prosimii= strepsirrhines plus tarsiers
similarities to anthropoidea:
anatomical haplorhiny
post-orbital closure
lack tapetum lucidum, therefore have large eyes, suggest re-acquired nocturnal lifestyle from a diurnal ancestor
similarities to strepsirrhines: unfused mandibular symphysis unfused frontal bone grooming claws multiple nipples
Haplorrhine fossil record
Tarsiers are sole living form from previously very diverse group “omomyids” or Tarsiiformes
Fossil strepsirrhine radiation= adapoids, nearly as diversity as “omomyids”
Darwinius marsillae, Mesel, Germany lagerstatte
Indications of erupting teeth, soft tissue impressions
47 Ma
First believed to be haplorrhine, but more data on hard tissue indicates in fact strepsirrhine
Aegyptopithecus: 2 premolars and F-S contact, but ear ring
Catopithecus: 2 premolars but ear ring and tarsier-like unfused mandible
Apidium: 3 premolars, ear ring, Z-P contact, distal tibia-fibula closely fused
Anthropoidea
Platyrrhini (new world), S. America, and Central America
Catarrhini (Old world, and apes)- Africa, Asia and Gibraltar
Differences between Platyrrhines and Catarrhines
Platyrrhini: nostrils point laterally 3 premolars zygomatic (jugal)- parietal temporal fossa articulation ectotympanic ring prehensile tail
Catarrhini: nostrils point inferiorly 2 premolars frontal- sphenoid temporal fossa articulation ectotympanic tube no prehensile tail`
Hominoid vs hominin
Hominoids: great apes (gibbon, orangutan, gorilla, chimpanzee, human)
Hominins: humans and stem relatives
Hominoid locomotion
all lack tail, have fewer lumbar vertebrae than other primates, shorter olecranon process of ulna, relatively large brains and bunodont molar cusps (blunt) Chimps and gorillas: knuckle-walking Orangutan: quadrumanal climbing Gibbon: brachiation Humans: bipedalism
Characters of habitual bipedalism
Foot:
adducted digit I
keystone cuboid maintains arch because dorsal margin wider than ventral margin
Knee:
valgus, holds weight of body closer to midline
oval femoral condyle keeps join stationary om resting posture w/o great muscular energy input
Pelvis: sagittal ilium (as opposed to coronal)- antero-posteriorly oriented, enables gluteal musculature to maintain balance efficiently
Inverted pendulum walk, takes advantage of inertia, depends less on muscular extension for propulsion
Australopithecus afarensis
eg. Mrs Ples, Taung child both small cranial capacities ventral foramen magnum S. Africa bipedalism evolved before brain size shows evidence in distal radius for knuckle walking
eg. Lucy
“striding terrestrial biped”
3.5Ma footprints, Laetoli trackway- only hominins around at that time
adducted hallux, modern foot proportions
4th metatarsal shows evidence for human-like arch (Ward et al., 2011)
BUT phalangeal curvature not statistically different to that of a chimp, indicates climbing capacity (because remodelled)
and scapula has more cranially oriented glenoid fossa and narrower infraspinatus fossa than humans
Ardipithecus ramidus
4.5Ma
sagittally oriented ilium - facultative biped
radius longer than tibia therefore arboreal capacity
abducted hallux
Australopithecus sediba
grasping and manipulative features:
thumb relatively long compared to digits 4 & 5
relatively wide distal phalanx of thumb (distal apical tuft)
competence in climbing:
prominent muscle scars for digital flexors
phalangeal curvature
Glires
> 2000 spp. (over half all placental mammals)
Groups:
Lagomorpha (rabbits, hares, pikas)
Scuiromorpha (squirrels, dormice, beavers, prairie dogs)
Myomorpha (mouse, rats, hamsters, jerboas, gophers)
Ctenohystrica (Laonastes, gundis, guinea pigs, mole rats, porcupines, cane rats)
Glires characters
enlarged anterior incisor is deciduous i2 (“gliriform”), not replaced
curved, evergrowing incisors
incisor enamel restricted to anterior band with dentine behind, enables self-sharpening
lack of canines and anterior premolars (diastema)
antero-posterior (palinal or “propalinal”) jaw movement
Differences between rodents and lagomorphs
Lagomorphs have: fenestrated rostral maxilla addition premaxillary tooth (i3) consistent loss of coronoid process consistently unrooted cheek teeth basicranial flexion calcaneal canal and fibular facet on calcaneus
Lagomorpha groups
Ochotonidae (pikas), Asia, N. America
Leponidae (hares and rabbits), Worldwide
successful in terms of biomass but not species numbers
