Question

Answer all the questions please

LAB EXERCISE Name Primates Through the Miocene 12.3 Section Date Materials Needed Station 1: Paleocene-The First Possible Primates (Alternative to Specimens: Figures A and B on page 336) 1 Compare a plesiadapiform primate with a strepsirhine. Fill in the table below with brief descriptions of the listed features for each. If using the figures provided rather than actual specimens, some features may not be visible. Station 1: A lemur or other strepsirhine anda Plesiadipis or other plesiadapiform skull cast O Station 2: Specimens of Adapis or other adapoid, a lemur or other strepsirhine, Necrolemur or other omomyoid, and a tarsier OStation 3: Specimens of Apidium, Aegyptopithecus, an Old World monkey skull, and an ape skull OStation 4: Specimens of Proconsul, an Old World monkey skull, Dryopithecus, and an African ape skull (gorilla or chimpanzee) OStation 5: Specimens of Sivapithecus, an orangutan, and an African ape skull (gorilla or chimpanzee) OStation 6: Specimens of Gigantopithecus (partial mandible) and a gorilla mandible Note: Figures in the lab manual may be used as alternatives to specimens. Skull Features Plesiadapiform Strepsirhine Postorbital bar (present or absent? Size and roundedness of braincase Position of orbits more forward-facing or laterally oriented? Incisor size relative to canines and molars Toothcomb (present or absent?) 2 Why do some researchers consider plesiadapiforms to be members of the primate order? (Consult the section on plesiadapiforms, page 315, if necessary) 3 Which of the plesiadapiform features are unlike those of primates? Consider both cranial and postcranial features (for the latter, look in the text for description of nails vs. claws and big toe opposability). Investigating the Past: Fossil Primates Chapter 12 335 A Plesiadapis. Ring-tailed lemur. Station 2: Adapoids and Omomyoids of the Eocene (Alternative to Specimens: Figures A through D) Look at the lab specimens at this station or altematively, Figures A through D on page 337. As you answer questions 1 and 2, consider such features as: (1) relative orbit size, (2) postorbital closure, (3) length of snout, and (4) features of the dentition. Be as detailed as possible in your answers. 1 In what ways is Adapis (or another adapoid) more similar to a lemur than to a tarsier? 2 In what ways is Necrolemur (or another omomyoid) more similar to a tarsier than to a lemur (despite its name)? 3 Considering the relative size of orbits of the tarsier, what can we tell about activity patterns (diurnal versus nocturnal) from fossilized remains? 4 Adapoids are thought to be ancestral to what modern forms? 5 Omomyoids may be ancestral to what modern group? LAB EXERCISE 12.3 continued Name 6 List five features that distinguish primates from most other mammals, and are visible in fossil remains. A B Adapis. Necrolemur C D cm 0 Ring-tailed lemur. Tarsier. Investigating the Past: Fossil Primates Chapter 12 337 Station 3: Oligocene Primates (Alternative to Specimens: Figures A through D) 1 Compare the skull (or Figure A) of the Fayum primate Apidium to those of Adapis and Necrolemur. How do they compare in terms of brain size and snout length? 2 Review the section on Apidium, page 318. How does its dental formula and ear region (bony ear tube or lack thereof) compare with those of a New World monkey (platyrrhine) and a member of the Old World monkey/ape group (catarrhine)? (These features are not visible from Figure A.) 3 Review the section on Aegyptopithecus, page 318. Compare its description to that of an Old World monkey and an ape in terms of dental formula and lower molar form (bilophodont vs. Y5 molar pattern). What is similar? What is different? A Apidium. C Old World monkey mandible (Hanuman langur). D Aegyptopithecus dental arcade. Ape mandible (orangutan). FT Station 3: Oligocene Primates (Alternative to Specimens: Figures A through D) 1 Compare the skull (or Figure A) of the Fayum primate Apidium to those of compare in terms of brain size and snout length? Adapis and Necrolemur. How do they 2 Review the section on Apidium, page 318. How does its dental formula and ear region (bony ear tube or lack thereof) compare with those of a New World monkey (platyrrhine) and a member of the Old World monkey/ape group (catarrhine)? (These features are not visible from Figure A) 3 Review the section on Aegyptopithecus, page 318. Compare its description to that of an Old World monkey and an ape in terms of dental formula and lower molar form (bilophodont vs. Y5 molar pattern). What is similar? What is different? Apidium. C Old World monkey mandible Hanuman langur) D Aegyptopithecus dental arcade. Ape mandible (orangutan). 338 Exploring Physical Anthropology Jwww.wwawag Old World monkey: lateral view of a vervet and dental arcade of a mandrill. 2 Which of the primates in the table on the previous page have/had a tail? How do you know? (Hint: It won't be from looking at the skulls!) 3 Which occurred earlier in time, Proconsul or Dryopithecus? 4 In what general region of the world was each of the above found? 5 Why is the timing of their existence significant in terms of the possible evolutionary relationship between the two? Exploring Physical Anthropology 340 LAB EXERCISE 12.3 continued Name Station 5: Sivapithecus (Alternative to Specimens: Figures A through C) 1 Compare Sivapithecus (below) to an orangutan and to an African ape. Fill in the table below with brief descriptions of the listed features in each. African ape Sivapithecus Orangutan Thickness of supraorbital ridge Interorbital distance (orbits closer together versus farther apart) Shape of orbits (more rounded vs. more squared) Size of zygomatic arch Size of central incisors compared to lateral ones A C Sivapithecus anterior and lateral views. Orangutan anterior and lateral views. Gorilla anterior and lateral views. (Figures are not to scale) Chapter 12 Investigating the Past: Fossil Primates 341

Answer 1

STATION 1:-

Answer 1)

• Plesiadapiform:-
  1. Postorbital bar is a characteristic feature of modern primates however it is absent in these primitive organisms due to facing of the orbits to the sides rather than positioned centrally facing forward as in humans.
  2. Size and roundedness of braincase:- The braincase is much flat, extended and less round in case of the Plesiadapiform. They were arboreal suggesting this hypothesis indicating absence of such modifications for showing presence of elongated snout and streamlined body.
  3. Position of orbital:- The orbitals were divergent and positioned laterally.
  4. Incisor size relative to Molar and canine:- The canines were larger in size than the incisors and the molars. The only difference lies in the morphology of incisors. They showed presence of many cusps.
  5. Toothcomb is absent in this extant group.
• Strepsirhine:-
  1. ​​​​​​​Postorbital bar is seen in Lemurs as they have modified vision as compared to the extant group.
  2. The braincase is short, rounded and supports the orbits present laterally as they show presence of a slightly elongated snout.
  3. Due to the smaller size of the braincase, the orbits are positioned laterally. They are posterior to snout.
  4. The incisors are smaller than the canines. They are located centrally and form a toothcomb pattern that is indicative of Lemurs or strepsirhines.
  5. Toothcomb is present.

​​​​​