Lab 13-Orders PRIMATES & SCANDENTIA

 

ORDER PRIMATES: shared and derived characters

 

1. locomotor characters:

·        grasping hands and feet with opposable pollux (thumb) and hallux (big toe)

·        hallux contains a nail

·        nails present on all or most digits (may be modified secondarily into a claw)

·        elongation of the calcaneus

·        hindlimb dominance during locomotion (except in brachiators)

·        center of gravity shifted towards hindlimbs

 

Strepsirhines:

lemur (Eulemur:  Lemuridae)

 

sifaka (Propithecus: Indridae)

 

potto (Arctocebus: Loridae)

 

aye-aye (Daubentonia: Daubentoniidae)

       Haplorhines:

 

 

tarsier (Tarsius: Tarsiidae)

marmoset (Callitrhrix: Callitrichidae)

 

spider monkey (Brachyteles: Cebidae)

gorilla (Gorilla:  Hominidae)

       hands (left) and feet (right) of strepsirhine (above) and haplorhine (below) primates

 

Locomotor styles among primates are perhaps more variable than any other group of mammals.  Those illustrated here include, from left to right:  arboreal plantigrade [note longer hind limbs] (lemur), arboreal vertical clingers and leapers (tarsier), terrestrial plantigrade [note longer forelimbs] (vervet monkey), terrestrial knuckle-walking (gorilla), brachiation [note extremely long forelimbs] (gibbon), bipedal terrestrial walking (chimpanzee)

 

2.  Stereoscopic vision

·        forward rotation of the orbits and narrowing of the interorbital distance

·        enlargement of the orbital cavity

·        exposure of the ethmoid bone on the inner orbital wall

·        stereoscopic vision in which approximately half of the retinal axons project to the ipsilateral side of the brain

·        complete postorbital bar or plate (plate of haplorhine primates unique among mammals)

3.  Auditory bulla bony; the floor formed by the petrosal bone, with tympanic ring or

tube present

4. Dentition

a.      dental formula with two incisors and three premolars (loss of one incisor and one premolar from primitive eutherian condition)

b.      molars tritubercular or quadritubercular, bunodont and brachydont

 

Phylogeny and classification

 

       Primates are traditionally divided into two suborders, the composition of which varies depending upon the placement of the tarsier (family Tarsiidae).  Older classifications tended to place tarsiers with lemurs and lorises, into the Suborder Prosimii, with monkeys and apes in the Suborder Anthropoidea.  Most primatologists now believe that tarsiers are wither more closely related to monkeys and apes, and thus define two suborders (Strepsirhini and Haplorhini) based on characteristics of the nose and the enclosed bony orbit, or regard tarsiers as a third group equally distinct from both prosimian and anthropoid primates.

 

       The classification in most common use at the moment is the following:

                                                                       

                                                      Suborder Strepsirhini

                                                                  Family Cheirogaleidae – dwarf lemurs

                                                                  Family Lemuridae – lemurs

                                                                     Family Megaladapidae – sportive lemurs

                                                                  Family Indriidae – woolly lemur and sifaka

                                                                  Family Daubentoniidae – aye-aye

                                                                  Family Loridae – lorises, potto

                                                                  Family Galagonidae – galagos

                                                       Suborder Haplorhini

                                                           Infraorder Tarsii

                                                                  Family Tarsiidae – tarsiers

                                                          Infraorder Platyrrhini

                                                                  Family Callitrichidae – marmosets, tamarins

                                                                  Family Cebidae – New World monkeys

                                                          Infraorder Catarrhini

                                                                  Family Cercopithecidae – Old World monkeys

                                                                  Family Hylobatidae – gibbons

                                                                  Family Hominidae – orangutan, gorilla, chimp, human

 

 

 

 

Suborder STREPSIRHINI

 

diagnostic characteristics:

 

1.      naked, glandular rhinarium with median cleft (called the philtrum) and slit-like nostrils (diverticulum nasi) directed laterally.  [This is the primitive condition for mammals in general.]

 

2.      presence of a tooth comb, composed of lower incisors and canine teeth (secondarily lost in Daubentoniidae) projecting forward from lower jaw, used in grooming (Tupaiidae [Scandentia] have a similar tooth comb, but one that does not include the canines)

 

 

3.      grooming claw on the second digit of the foot

 

 

Family LEMURIDAE

       (lemurs)

 

general characters:

1.      size medium (50-100 cm)

2.      limbs subequal in length

3.      digits each bearing a nail, except for 2nd digit of hindfoot which bears a claw

4.      tail long, furred

5.      fur woolly

6.      ventral surface of hindfoot naked

7.      braincase elongate

8.      rostrum elongate

9.      orbits large, usually with prominent ridge around each

10. ectotympanic ring in bulla free, not fused ventrally to petrosal bulla

11. upper incisors uniformly small, peg-like, with median diastema

12. molars tritubercular

 

 

range:  Madagascar, Comoro Islands

 

 

Family CHEIROGALEIDAE

       (dwarf and mouse lemurs)

 

 

defining characters:  similar in cranial details to true lemurs, but differ by being very small to small (12-30 cm) and the upper incisors are well developed, not small and peg-like, and are not separated by a median diastema.  As with other lemurs, a tooth comb comprised of the incisors and canines is present on the lower jaw.

 

genera:  Microcebus (mouse lemurs), Allocebus (dwarf lemurs), Phaner (fork-marked lemurs)

 

pygmy mouse lemur (Microcebus myoxinus)

 

Family MEGALADAPIDAE

       (sportive lemurs)

 

 

defining characters:  similar in cranial details to true lemurs, but lack upper incisors in adults and lack the bold markings often characterizing true lemurs.

 

genera:  monotypic – Lepilemur (sportive lemurs)

sportive lemur (Lepilemur mustelinus)

Family INDRIIDAE                                                                         Family DAUBENTONIIDAE

(indri, sifakas, woolly lemurs)                                                                                                       (aye-aye)     

Verreau’s sifaka (Propithecus verreauxi)

 

aye-aye (Daubentonia)

 

 

 

 

 

Family LORIDAE (often incorrectly spelled LORISIDAE)

       (pottos, lorises)

 

 

general characters:

1.      size relatively small (18-80 cm)

2.      hindlimbs much longer than forelimbs

3.      digits each bearing a nail except for the 2nd digit of hindfoot, which bears a claw

4.      tail very short or absent

5.      fur soft, dense, somewhat woolly

6.      ventral surface of hindfoot haired at heel

7.      rostrum short

8.      braincase spherical

9.      orbits large, usually with prominent ridge around each

10. ectotympanic ring fused to petrosal bulla ventrally

11. upper incisors uniformly very small, peg-like, and with median diastema

12. lower incisors usually comb-like, procumbent

13. lower canine incisiform

14. molars quadritubercular

 

 

dental formula:

 1-2  1  3  3 

   2   1  3  3

 

= 34-36

 

genera:  Arctocebus (potto), Loris (slender loris), Nycticebus (slow lorises), Perodictus (potto)

 

range:  Africa, south of the Sahara; India and Sri Lanka; Southeast Asia; East Indies.

 

 

 

 

 

 

 

slender loris (Loris)

 

 

potto (Perodicticus potto)

 

 

 

slender loris (Loris tardigradus)

 

 

Family GALAGONIDAE

       (galagos or bush babies)

 

       general characters:

1.      small size (like a squirrel), large eyes, expressive ears that resemble those of some bats

2.      tail long and well furred

3.      hindlimbs especially long with powerful thigh muscles

4.      skull with long rostrum

5.      lower incisors and canines procumbent, specialized as tooth-comb (used in grooming and feeding on tree resin)

6.      ectotympanic ring fused to petrosal bulla ventrally

7.      both pollux and hallux large and opposable

8.      4th digits are unusually long

9.      distal most pad of all digits with well developed traction ridges used in climbing

10. 2nd digit of hindfoot short and bears a claw for grooming; all other digits with flattened nails

11. hindfoot especially elongated (tarsal elements), for springing locomotion

 

dental formula:

 2  1  3  3 

 2  1  3  3

 

= 36

 

genera:  Galago (bush babies), Galagoides (dwarf bush baby), Otolemur (thick-tailed bush baby)

 

range:  Africa, south of the Sahara

 

 

 

Otolemur (thick-tailed bush baby)

 

 

Suborder HAPLORHINI

 

diagnostic characters:

 

1.  nose with simple nostrils, no rhinarium, philtrum vestigial or absent; internarial breadth wide in Tarsius and all platyrrhines (with nostrils directed somewhat laterally) and comparatively narrow in all catarrhines (with nostrils directed forward)

 

 

  1. orbit and temporal fossa separated by postorbital plate (see illustrations above)

 

  1. braincase relatively large and rounded, not elongated

 

  1. foramen magnum more or less directly ventrally

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Infraorder TARSII

 

Family TARSIIDAE

       (tarsiers)

 

general characters:

1.      size relatively small (20-45 cm)

2.      hindlimbs longer than forelimbs

3.      claws on 2nd and 3rd digits of hindfoot and nails on remaining digits

4.      digits very elongate, terminating in enlarged discs

5.      tail long, naked or sparsely haired, often tufted at end

6.      rostrum short

7.      orbits enormous, with prominent ridge around each

8.      orbit incompletely walled off from temporal fossa

9.      auditory bulla extending laterally as a bony tube

10. upper and lower incisors well developed, not equal in size; no median diastema in upper incisors; lower incisors vertical, not procumbent

11. molars tritubercular

 

 

dental formula:

 2  1  3  3 

 1  1  3  3

 

= 34

 

genera:  the family is monotypic – Tarsius (tarsier)

 

range:  Indonesian and Philippine islands

 

 

 

tarsier (Tarsius)

 

 

 

 

upper right molars

 

1st and 2nd lower left molars

 

tarsier (Tarsius)

 

Infraorder PLATYRRHINI

 

   Platyrrhine primates are exclusive to the New World, and include the traditional families Callitrichidae (tamarins and marmosets) and Cebidae (howler, spider, capuchin, woolly, squirrel, owl, titi, saki, and other monkeys).  Sometimes Goeldi’s monkey (Callimico) is placed in its own family, the Callimiconidae.  Phylogenetic analyses, including both anatomical characters as well as molecular sequences, however, suggest that this simple arrangement is incorrect.  The tree below (from Horovitz, I.  1999.  A phylogenetic study of living and fossil platyrrhines.  American Museum Novitates, no. 3269) illustrates one phylogenetic arrangement that places the owl monkey (Aotus) and a clade comprised of the capuchins (Cebus) and squirrel monkeys (Saimiri) as sisters to the tamarins/marmosets, with the larger monkeys arranged in two clades (the Pithecidae and Atelidae).  We will follow the traditional division of the Callitrichidae (including Callimico) and Cebidae here, but you should be aware of recent suggested changes.

 

   Platyrrhines are differentiated from the Old World catarrhine monkeys and apes by the following characters:

1.      three premolars above and below, instead of two

2.      nostrils directed laterally, as opposed to forward

3.      prehensile tail present (in some genera only; unique among primates)

4.      no ischial callosities (not present in catarrhine family Hominidae)

5.      dichromatic, rather than trichromatic, color vision (except howler monkey)

 

 

Family CALLITRICHIDAE

       (marmosets and tamarins)

 

general characters:

1.      size small (30-90 cm)

2.      forelimbs approximately equal in length to hindlimbs

3.      pollex not opposable; hallus opposable

4.      digits each bearing a claw except for hallux, which bears a flat nail

5.      tail long, not prehensile

6.      auditory bulla not extending laterally as bony tube

7.      molars tritubercular

8.      three premolars and two molars above and below (except Callimico, which has three molars)

 

 

dental formula:

 2  1  3  2 

 2  1  3  2

 

= 32  (3 molars above and below in Callimico)

 

genera:  Callimico (callimico – sometimes placed in own family, Callimiconidae), Callithrix (tamarins), Cebuella (pygmy marmoset), Leontopithecus (lion tamarins), Saquinus (tamarins)


range:  New World tropics, from Panama to southern Brazil

Saguinus (tamarin)

 

 

 

tassel-eared marmoset

(Callithrix humeralifera)

 

 

 

 

golden-mantle tamarin

(Saguinus tripartitus)

faces of (top to bottom):

emperor tamarin (S. imperator); black-chested moustached tamarin (S. mystax); cotton-top tamarin (S. oedipus).

Family CEBIDAE

   (New World monkeys)

 

 

general characters:

1.      size small to medium (65-190 cm)

2.      forelimbs may be longer or shorter than hindlimbs

3.      pollex only slightly opposable or absent (Ateles), Brachyteles; hallux opposable

4.      digits each bearing a flattened or narrow, keeled nail

5.      tail short (Cacajao) or long, prehensile in some (Ateles, Alouata, Cebus, Lagothrix)

6.      auditory bulla not extending laterally as a bony tube

7.      molars quadritubercular

8.      three premolars and molars above and below

 

 

dental formula:

 2  1  3  3 

 2  1  3  3

 

= 36

 

genera:  Alouatta (howlers), Aotus (owl, or night, monkey), Ateles (spider monkey), Brachyteles (woolly spider monkey), Cacajao (Uakari), Callicebus (titi monkeys), Cebus (capuchins), Chiropotes (bearded saki monkeys), Lagothrix (woolly monkeys), Pithecia (saki monkeys), Saimiri (squirrel monkeys)

 

range:  New World tropics from southern Mexico to northern Argentina

 

 

 

 

 

 

Ateles (spider monkey)

 

 

 

 

 

 

 

 

 

1st and 2nd upper right molars of a saki monkey (Pithecia)

 

 

 

noisy owl monkey (Aotus vociferans)

 

 

 

brown capuchin (Cebus apella)

 

 

 

 

 

 

 

Infraorder CATARRHINI

 

       Catarrhine primates are exclusively Old World (except humans, now cosmopolitan), and include three families:  the Cercopithecidae (Old World monkeys, such as macaques, baboons, mandrills, langurs, and leaf-eating monkeys); the Hylobatidae (gibbons); and Hominidae (the great apes, including humans).  Older classifications include the gibbons and great apes together in the family Pongidae separate from Hominidae, which only includes Homo among extant mammals, but both morphological and molecular data strongly support the very close affinity of humans with chimpanzees and gorillas, and less so with the orang, as members of the family Hominidae.

 

       Catarrhines can be distinghished from New World platyrrhines by the following characters:

1.      two premolars above and below, instead of three

2.      nostrils close together and directed forward and downward, not laterally

3.      skull typically robust and heavily ridged, often with a sagittal crest

4.      ischial collisities present (except in Hominidae)

5.      prehensile tail absent in all taxa, even those with long tails

6.      trichromatic color vision

7.      bony shelf (simian shelf) present at posterior border of jaw symphysis in most taxa (notably absent in humans)

 


Family CERCOPITHECIDAE

       (macaques, baboons, langurs, leaf monkeys, and others)

 

general characters:

1.      size medium (70-185 cm)

2.      forelimbs slightly longer than hindlimbs

3.      pollex opposable, if present; hallux opposable

4.      digits each with flattened nail

5.      tail absent or, if present, not prehensile

6.      ischial callosities present

7.      auditory bulla extending laterally as a bony tube

8.      molars above and below quadritubercular (except for lower m3, which has a well developed hypoconulid); bunodont, but with cusps connected by weakly developed transverse lophs

9.      molars square or rectangular in shape, with cusps opposite

 

dental formula:

 2  1  2  3 

 2  1  2  3

 

= 32

 

genera:    subfamily Cercopithecinae:  Cercocebus (mangabeys), Cercopithecus (guenons), Erythrocebus (patas monkey), Macaca (macaques), Mandrillus (drill), Papio (baboons), Theropithecus (gelada baboon)

                 subfamily Colobinae:  Colobus (colobus monkeys), Nasalis (proboscis monkey), Presbytis (leaf-eating monkeys), Pygathrix (snub-nosed monkeys), Semnopithecus (langurs)

 

range:  Old World tropics and subtropics, from southwestern Europe (Gibralter) east to Japan, Africa, and southern Asia (India, Southeast Asia, Indonesia, Philippine Islands)

 

 

 

 

Papio (baboon)

Colobus (black and white colobus)

 

 

 

 

 

2nd and 3rd upper right molars

orange-crowned mangaey

(Cercocebus torquatus)

 

2nd and 3rd lower molars

baboon

(Papio hamadryas)

[note enlarged hypoconulid on m3 and transverse lophs on all teeth]

 

 

 

 

 

 

Baboon (Papio hamadryas)                                                                                                          Rhesus macaque (Macaca mulatta)

 

 

 

 

 

 

 

 

Family HYLOBATIDAE (gibbons and siamang)

 

general characters:

1.      size medium, 4 to 11 kg

2.      no sexual dimorphism

3.      forelimbs extremely elongated for brachiation (over twice length of body)

4.      hindlimbs also elongated, but shorter than forelimbs

5.      pollex reduced but opposable, separated from 2nd digit by deep cleft

6.      hallux opposable

7.      digits with flattened or slightly keeled nail (except pollux and hallux, which lack either claws or nails)

8.      ischial collisities present, but small

9.      no tail

10. no sagittal crest

11. auditory bulla extending laterally as bony tube

12. canines prominent

13. molars bunodont, cusps separate without transverse lophs, cusps somewhat oblique

 

dental formula:

 2  1  2  3 

 2  1  2  3

 

= 32

genera:  the famil is monotypic  -  Hylobates (gibbons and siamangs)

 

range:  Southeast Asia, including Indonesia

 

 

gibbon skull and upper molars (Hylobates lar)

Family HOMINIDAE

       (great apes)

 

 

general characters:

1.      size large to very large

2.      strong sexual dimorphism

3.      forelimbs longer than hindlimbs in orang, gorilla, and chimp; reverse in humans

4.      pollux and hallux  well developed and opposable (except latter in humans)

5.      all digits with flattened nails

6.      no ischial callosities

7.      no tail

8.      sagittal crest often prominent

9.      auditory bulla extending laterally as a tube

10. canines well developed in all taxa except humans

11. molars quadrituberdular, bunodont, cusps obliquely arranged

 

Range:

     orang (Pongo)    – Sumatra and Borneo

     gorilla (Gorilla)    – equatorial Africa

     chimp (Pan)        – equatorial Africa

     humans (Homo) – cosmopolitan

 

 

dental formula:

 2  1  2  3 

 2  1  2  3

 

= 32

 

genera:  Pongo (orang-utan), Gorilla (mountain and lowland gorillas), Pan (pygmy [=bonobo] and common chimpanzee), Homo (humans)

 

 

 

 

 

 

 

 

 

 

Pan (common champanzee)

 

 

 

Right upper molars orang (Pongo pygmaeus)

Homo (human)

ORDER SCANDENTIA

 

Family TUPAIIDAE

       (tree shrews)

 

general characters:

1.      body size (20-40 cm) and form squirrel-like

2.      hindlimbs and forelimbs subequal in size

3.      snout moderately slender, pointed

4.      auditory bulla not enlarged

5.      no palatal perforations

6.      postorbital process large, contacting zygomatic arch to form complete postorbital bar

7.      zygomatic arch perforate

8.      molars with three principal cusps, fourth cusp is very small

9.      occlusal surface of upper molars with weakly developed W-shaped ectoloph

dental formula:

 2  1  3  3 

 3  1  3  3

 

= 38

 

genera:  Ptilocercus (pen-tailed tree shrew), Tupaia (tree shrew), Urogale (Philippine tree shrew)

 

range:  Southeast Asia, including Indonesian and Philippine islands

 

 

 

 

 

 

Tupaia (common tree shrew)

 

 

 

 

 

upper right (above) and lower left (below) cheekteeth (premolar 3, molars 1-3) of a ccommon tree shrew, Tupaia

 

Tupaia minor (pygmy tree shrew)

 

Ptilocercus lowii (pen-tailed tree shrew)