Neanderthal anatomy

Comparison of faces of early European Homo sapiens (left) and Homo neanderthalensis (right) based on forensic facial reconstructions exhibited at the Neanderthal Museum.

Ashley Montagu claimed humans have more neotenized skulls than Neanderthals.[6]

Neanderthal cranial anatomy

Neanderthal footprint in the Natural History Museum in Prague

Reconstruction of the head of a Homo neanderthalensis (type of the humans found in Shanidar 1)

A reconstruction of a Neanderthal male at Zagros Paleolithic Museum (2008)

The magnitude of autapomorphic traits in specimens differ in time. In the latest specimens, autapomorphy is unclear.

The following is a list of physical traits that distinguish Neanderthals from modern humans. However, not all of them distinguish specific Neanderthal populations from various geographic areas, evolutionary periods, or other extinct humans. Also, many of these traits are present in modern humans to varying extent due to both archaic admixture and the retention of ancestral hominid traits shared with Neanderthals and other archaic humans. Nothing is certain (from unearthed bones) about the shape of soft parts such as eyes, ears, and lips of Neanderthals.[7]

While the structure of the head and face were not very far removed from those of modern humans, there were still quite noticeable differences. Notably the neanderthal head is much longer, with a more pronounced facial front. The Neanderthal chin and forehead sloped backwards and the nose region protruded forward more than in modern humans. The common shapes of the nose are not known but in general it was likely more robust, and possibly slightly larger, than in modern humans. The brain space of the skull, and so most likely the brain itself, were larger than in modern humans.

When comparing traits to worldwide average present day human traits in Neanderthal specimens, the following traits are distinguished. The magnitude on particular trait changes with 300,000 years timeline. The large number of classic Neanderthal traits is significant because some examples of paleolithic and even modern Homo sapiens may sometimes show one or even a few of these traits, but not most or all of them at the same time.

In October 2018, scientists announced the 3-D virtual reconstruction, for the first time, of a Neanderthal rib cage, which may help researchers better understand how this ancient human species moved and breathed.[8][9]

In February 2019, scientists reported evidence that Neanderthals walked upright much like modern humans.[10][11]

• Cranial
  • Sloping forehead
  • Suprainiac fossa, a groove above the inion
  • Occipital bun, a protuberance of the occipital bone, which looks like a hair knot[12]
  • Projecting mid-face (midsagittal prognathism)
  • Projecting jaws (maxillary and mandibular prognathism)
  • Less neotenized skull than of a majority of modern humans[6]
  • Low, elongated skull with flat lambdoid region
  • Broad cranial vault with "en bombe" parietal morphology
  • A flat basicranium[13][14][15]
  • Supraorbital ridge, a prominent, trabecular (spongy) brow ridge
  • 1,500–1,740 cm³ (92–106 cu in) cranial capacity (modern human: 1425 cm³)
  • Lack of a protruding chin (mental protuberance; although later specimens possess a slight protuberance)
  • Crest on the mastoid process behind the ear opening
  • No groove on canine teeth
  • A retromolar space posterior to the third molar
  • Broad nose
  • Bony projections on the sides of the nasal opening, projecting nose
  • Distinctive shape of the bony labyrinth in the ear
  • Larger mental foramen in mandible for facial blood supply
• Sub-cranial
  • Considerably more robust, stronger build
  • Long clavicles (however, Neanderthal clavicles are not relatively long and are proportionately similar to those of modern humans[16])
  • Broad shoulders and pelvis
  • Large, wide shoulder blades
  • Broad chest
  • Barrel-shaped or bell-shaped rib cage and no waist[17] (unclear and debated)
  • More laterally curved radius with a radial tuberosity placed more medially, a longer radial neck, a more ovoid radial head, and a well-developed interosseous crest.[18]
  • Curved limbs
  • On the ulna, the trochlear notch is facing more anteriorly, the brachialis insertion is lower, the mid-shaft is larger, and the shaft is more sinusoidal.[18]
  • Thick joints
  • Large hands and feet
  • Larger round finger tips
  • Large kneecaps
  • Thick, bowed shaft of the thigh bones, bowed femur
  • Short tibiae
  • Short fibulae
  • Large calcaneus.[19]
  • Long, gracile pelvic pubis (superior pubic ramus)

Within the west Asian and European record, there are five broad groups of pathology or injury noted in Neanderthal skeletons.

Developmental stress

Neanderthal child

Two non-specific indicators of stress during development are found in teeth, which record stresses, such as periods of food scarcity or illness, that disrupt normal dental growth. One indicator is enamel hypoplasia, which appears as pits, grooves, or lines in the hard enamel covering of teeth. The other indicator, fluctuating asymmetry, manifests as random departures from symmetry in paired biological structures (such as right and left teeth). Teeth do not grow in size after they form nor do they produce new enamel, so enamel hypoplasia and fluctuating asymmetry provide a permanent record of developmental stresses occurring in infancy and childhood. A study of 669 Neanderthal crowns showed that 75% of individuals suffered some degree of hypoplasia. Two studies,[25][26] compared Neanderthals with the Tigara, coastal whale-hunting people from Point Hope Alaska, finding comparable levels of linear enamel hypoplasia (a specific form of hypoplasia) and higher levels of fluctuating asymmetry in Neanderthals. Estimated stress episode duration from Neanderthal linear enamel hyoplasias suggest that Neandertals experienced stresses lasting from two weeks to up to three months.

Neanderthal children may have grown faster than modern human children. Modern humans have the slowest body growth of any mammal during childhood (the period between infancy and puberty) with lack of growth during this period being made up later in an adolescent growth spurt.[27][28][29] The possibility that Neanderthal childhood growth was different was first raised in 1928 by the excavators of the Mousterian rock-shelter of a Neanderthal juvenile.[30] Arthur Keith in 1931 wrote, "Apparently Neanderthal children assumed the appearances of maturity at an earlier age than modern children."[31] The rate of body maturation can be inferred by comparing the maturity of a juvenile's fossil remains and the estimated age of death.

Wezmeh Child maxillary right premolar tooth (P3 or possibly P4) of an individual between 6–10 years old from Wezmeh Cave

The age at which juveniles can be indirectly inferred from their tooth morphology, development and emergence. This has been argued to both support[32] and question[33][34] the existence of a maturation difference between Neanderthals and modern humans. Since 2007, tooth age can be directly calculated using the noninvasive imaging of growth patterns in tooth enamel by means of x-ray synchrotron microtomography.[35]

This research supports the occurrence of much more rapid physical development in Neanderthals than in modern human children.[36] The x-ray synchrotron microtomography study of early H. sapiens sapiens argues that this difference existed between the two species as far back as 160,000 years before present.[37]

More recent research, published in September 2017 and based on a more complete skeleton of a Neanderthal juvenile (7.7 years old) found in a 49,000 year old site in Northern Spain, indicates that Neanderthal children actually grew at a similar rate to modern humans. Researchers were able to examine dental, cranial, and postcranial material, allowing the assessment of dental and skeletal maturation with age. In fact the main difference between Neandertals and modern humans was reported in the vertebral column. Several features also indicated ongoing brain growth. It was observed that the pattern of vertebral maturation and extended brain growth might reflect the broad Neanderthal body form and physiology, rather than a fundamental difference in the overall pace of growth in Neanderthals compared to modern humans.[38]