Paenungulata → sub-ungulates - Hyracoidea - hyraxes - Sirenia - manatees and sea cows - Proboscidea - elephants - Strong DNA Similarity - Hyraxes most likely sister taxon to Proboscidea + Sirenia (Tethytheria) Morphological synapomorphies - all paenungulates - Fancy tongue muscle (split styloglossus) - Long pre-sacral vertebral column - Paired mammary glands and teats located behind forelimbs (+4 teats near groin in hyraxes) - Big animals slow down metabolism due to large size - Few, if any, predators (this is what allows you to slow metabolism down) Hyracoids + elephants - Toenails- Sensitive pads on feet (can sense vibrations) - Tusks - Deep lower jaw (for grinding)- Good memory Hyracoidea- Family Procaviidae - hyraxes, dassies, coneys - 3 genera and ~11 species - Africa and Middle East - Earliest fossils from Eocene of Morocco - Diverse in Paleogene (runners, climbers) - Diversity declined in Miocene - Dendrohyrax: browser (south of Sahara) - Procavia, Heterohyrax: grazers (mid. East open areas S. of Sahara) - 7+ month gestation, 1-2 young/litter - Herbivorous (cecal fermentation - plant feeding) - Prefer rocky outcrops (trees for Dendrohyrax) - Diurnal with polygynous family groups - Diurnal = active during the day - Name for organisms active during twilight times of day: crepuscular- Use behavioral thermoregulation (basking) - Sweat through feet - Body is covered in fur so they may be able to do it that way since there’s no furHyracoidea teeth: - Incisors ever-growing- Diastema. No canines - Enamel on anterior of incisors (as in rodents) - Pectinate (comb-like) lower incisors. Why? - Cleaning each other Hyracoidea feet: - Four toes on forefeet; three toes on hind feet - Feet mesaxonic (large toe is central) - Digits of pes bear flattened nails (except clawed second digit) Cavies = guinea pigs - Rodentia - Family Caviidae - South america Hyracoids converge with cavies: - Incisors, diastema, and cheek teeth (lophodont ridges) Dendrohyrax- Soles of feet naked, glandular secretions keep soles moist. How is this beneficial? - Suction cup- Low-crowned molars and premolars - Arboreal browsers - Surprisingly agile in trees Heterohyrax - yellow-spotted rock hyraxProcavia - rock hyrax - share outcrops and nurseries (mixed group of young) Procavia- Live in rocky outcrops in arid grassland - Form large colonies, dominant males defend a group of females - Nest among the rocks, graze alongside - Double cecum - How would that inform you about how they live? - You can go for plant food that most other organisms won’t be able to breakdown Sirenia - Dugongs and manatees - Completely aquatic herbivores- 2 genera and 4 species - Weights above 1500 kg- Nearly hairless, thick skin- Nostrils valvular - Why need them if you aren’t a fast swimmer - Slow metabolic rate so it helps conserve energy - Thick dentary bone - Middle ear bones are massive - Provide you with the low frequency communication - Dense, heavy bones provide ballast - Less predation - Five-toes manus enclosed in flipper - Pelvis vestigial, hind limbs absent - Tail is horizontal fluke Desmostylian - Paleoparadoxia - Pacific Rim, 20-10 MYA Prorastomus: early Eocene of Jamaica - Still capable of terrestrial locomotion Sirenia teeth- Cheek teeth columnar - Covered with cementum (dugongs) or enamel (manatees) - Tooth replacement as in elephants: back-to-front conveyor belt why? - Takes time to grow so you need them right away - Probs eating sea grass easy chewing material Sirenia- Inhabit coastal seas, large rivers and lakes - Slow moving grazers - Slow metabolism and little body fat - Restricted to warmer waters - Lek: mating arena - Alpha male: will be most successful and mate with the most females - Beta male: not very successful - Gamma male: may not breed at all - Sneaker males: swerve in and mate with female while other males are fighting - Make complex sounds - Long-lived with low reproductive
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