The place of the Neanderthals in hominin phylogeny

Journal of Anthropological Sciences, 2007

Species boundaries in the fossil record are frustratingly elusive to recognize, largely because of the untidy way in which biological diversity is "packaged". Accepting that species are most fundamentally "individuals," with origins, births, and extinctions, rather than essentialist collections of traits, means also accepting that neither qualitative nor quantitative assessments of morphology will provide an infallible guide to species status. Beyond a certain level of diff erentiation the problem ceases, however, and this level is comfortably exceeded by Homo neanderthalensis. What is more, the Neanderthals appear not simply to constitute a separate species lineage, but to form part of a larger endemic European clade to which such distinctive forms as the Sima de los Huesos and Steinheim fossils also belong. Th is clade has a contemporary occurrence in Europe with the larger and more cosmopolitan species Homo heidelbergensis (exemplifi ed by specimens such as those from Arago, Petralona, Kabwe, and Bodo, and probably also Dali and Jinniushan), showing that hominid history in this region is more complex than simply that of a sincle lineage evolving toward the terminal species Homo neanderthalensis.

This article focuses on the ongoing debate regarding whether Neanderthals should be classified as a subspecies of Homo sapiens or as an entirely separate species. Several lines of evidence are explored, including recent genetic evidence, which suggest that despite rare interbreeding events, Neanderthals should in fact be classified as a separate species.

This paper, containing a comparative analysis of research done in the fields of genetics and morphology as pertains to studying early human evolution, takes a neutral stance on both the research conducted and the field of paleoanthropology. It provides the reader with information concerning the plausibility of hybridization between Homo Neanderthalensis and Homo Sapiens, with proofs offered via comparisons of HLA alleles and analogies to the understood development of hybrids in Camelidae. It also includes a summary of the current limitations posed by both genetic testing and morphology as relates to the accuracy of species classification efforts in beings more than a few hundred years old.

Proceedings of The National Academy of Sciences, 1999

2012

In researching this article review, the author found the evidence discovered in the most recent scientific experiments to be far more fascinating than those uncovered so many years before, which were found to be, as they have been described, correctly, even presciently, by the scientists themselves as being “outdated”, on occasion only just shortly following their publication. However, this writer also went to great lengths to recognize the relevance and even significance of the previous discoveries in the context of setting the proper precedent upon which the proceeding experiments that followed were to be founded. Throughout the course of writing this review, what is by far the greatest obstacle encountered has been the fact that, in the commentary in 1999, Tattersall and Schwartz were debunking a scientific proposition, namely that there were Neanderthal biological contributions to modern humans, which when considered in the light of the most contemporary research as mentioned above, appears all but irrefutable. Given the most current science, there is little choice but to conclude that Trinkaus’s, Duarte’s, and their Portuguese archaeological team’s discoveries, if not the conclusions they drew from their findings, were closer to what is now known to be the truth than were Tattersall’s and Schwartz’s critiques of those findings. Even when, more than a decade after he and his colleague wrote their critique of the hybridization hypothesis, new evidence came to light that resoundingly proved a contribution to modern humans by Neanderthals at the most foundational biological level, in our genes, it is especially notable by this author as being nothing short of extraordinary the graciousness, degree of humility, and downright enthusiasm with which Doctor Tattersall himself personally welcomed the genuinely revolutionary scientific discoveries of this new century.

2024

Currently, the existence of the Neanderthal genome in our DNA is an undeniable fact. The European territory provides us with several archaeological sites which fossil record demonstrates this evidence. Neanderthals formed small communities, but interbred with other species and with other Neanderthal groups. The severity and intensity of these relationships, along with the chronologies, genetic indices and occupations within the European context, are highlighted in the current study.

Neanderthal extinction is still under debate and there are two main schools of thought on this topic: (1) Neanderthals and modern humans are two distinct species and (2) Neanderthals and modern humans are a single species, with or without two subspecies. Recently, a new hypothesis has risen up, which takes into account arguments from both schools: the Neanderthal speciation by distance (i.e. Voisin 2006c). This hypothesis is based on a morphological cline from East to West in Neanderthal populations. In other words, the farther those populations lived to the west, the more they displayed pronounced Neanderthal characters. The aim of this study is to test the speciation by distance hypothesis in Neanderthal in regard to the shoulder complex. The shoulder girdle displays a morphological cline from East to West, but only for architectural characters and not for functional ones. This cline could be better explained by a result of a speciation by distance induced by genetic drift than by a different response to any physical activities. This study tends to confirm the speciation by distance model for Neanderthal, even if more studies are needed to confirm it firmly.

Journal of Molecular Evolution, 2007

The retrieval of Neanderthal (Homo neanderthalsensis) mitochondrial DNA is thought to be among the most significant ancient DNA contributions to date, allowing conflicting hypotheses on modern human (Homo sapiens) evolution to be tested directly. Recently, however, both the authenticity of the Neanderthal sequences and their phylogenetic position outside contemporary human diversity have been questioned. Using Bayesian inference and the largest dataset to date, we find strong support for a monophyletic Neanderthal clade outside the diversity of contemporary humans, in agreement with the expectations of the Out-of-Africa replacement model of modern human origin. From average pairwise sequence differences, we obtain support for claims that the first published Neanderthal sequence may include errors due to postmortem damage in the template molecules for PCR. In contrast, we find that recent results implying that the Neanderthal sequences are products of PCR artifacts are not well supported, suffering from inadequate experimental design and a presumably high percentage (>68%) of chimeric sequences due to ''jumping PCR'' events.

"Varying scientific paradigms interpret the middle to late Pleistocene Neanderthal to be a distinct species, Homo neanderthalensis, a subspecies of anatomically modern humans, Homo sapiens neanderthalensis, or as an ancestor to Homo sapiens in certain contexts across Europe. Literature that examined Neanderthals from each scientific perspective using fossils, tool technologies, and other manipulated material artifacts from the archaeological record was reviewed. The morphological evidence and its behavioral implications understood from fossils were explored using the cohesion species concept, which evaluates populations on potential pre-mating and post-mating isolation mechanisms. Neanderthal neonates, including a specimen from Mezmaiskaya Cave in Russia, exhibited similar patterns of growth prior to, and just following, birth as compared with anatomically modern humans. Adult Neanderthal fossils illustrate pelvis anatomy and overall robusticity analogous to Homo sapiens sensu stricto, especially when compared to northern populations of anatomically modern humans. Examples of hybrid individuals exhibiting a mixture of Neanderthal and anatomically modern human traits, such as Muierii 1, infer that mating was possible. The archaeological evidence suggests that Paleolithic tool technology, such as early Aurignacian assemblages, cannot solely be associated with Homo sapiens sensu stricto. Linking Neanderthals to these tool traditions illustrate that they were likely capable of similar activities, both symbolic and practical. After looking at multiples lines of evidence, I propose that Neanderthals are more likely to be a subspecies of anatomically modern humans, and should be referred to as Homo sapiens neanderthalensis. This is supported by recent mitochondrial and nuclear DNA evidence that reveal Neanderthals had small population sizes and interbred with Eurasian populations of modern humans. Defining Neanderthals as a subspecies of anatomically modern humans has implications for understanding the evolution of our behavioral capacity and social complexity. Furthermore, designating Neanderthals as Homo sapiens neanderthalensis impacts models of human origins, specifically the Out of Africa Model, and requires further research to understand the biological and cultural contributions Neanderthals made to the Homo sapiens lineage. "