Phylogenetic Continuity Research Articles

Neural bases of the non-conscious perception of emotional signals

Many emotional stimuli are processed without being consciously perceived. Recent evidence indicates that subcortical structures have a substantial role in this processing. These structures are part of a phylogenetically ancient pathway that has specific functional properties and that interacts with cortical processes. There is now increasing evidence that non-consciously perceived emotional stimuli induce distinct neurophysiological changes and influence behaviour towards the consciously perceived world. Understanding the neural bases of the non-conscious perception of emotional signals will clarify the phylogenetic continuity of emotion systems across species and the integration of cortical and subcortical activity in the human brain.

The fellowship of the hobbit: the fauna surroundingHomo floresiensis

AbstractThe Late Pleistocene Flores fauna shows a pattern observed on many other islands. It is neither aberrant nor exclusive, but the result of non‐random selective forces acting upon an impoverished and disharmonic insular fauna. By comparing the Flores vertebrate fauna with other fossil insular biotas, it is apparent that the evolution ofHomo floresiensisis part of a general pattern affecting all the inhabitants of Pleistocene Flores. Vertebrate evolution on Flores appears to have been characterized by phylogenetic continuity, low species richness and a disharmonic fauna. All three aspects stem from the isolated position of the island and have resulted in the distinct morphological characteristics of the Flores fauna. Evidence reviewed herein shows that features exhibited byH. floresiensis, such as small stature, a small brain, relatively long arms, robust lower limbs and long feet, are not unique, but are shared by other insular taxa. Therefore, the evolution ofH. floresiensiscan be explained by existing models of insular evolution and followed evolutionary pathways similar to those of the other terrestrial vertebrates inhabiting Pleistocene Flores.

Chimpanzee mothers at Bossou, Guinea carry the mummified remains of their dead infants

The forests surrounding Bossou, Guinea, are home to a small, semi-isolated chimpanzee community studied for over three decades [1]. In 1992, Matsuzawa [2] reported the death of a 2.5-year-old chimpanzee (Jokro) at Bossou from a respiratory illness. The infant's mother (Jire) carried the corpse, mummified in the weeks following death, for at least 27 days. She exhibited extensive care of the body, grooming it regularly, sharing her day- and night-nests with it, and showing distress whenever they became separated. The carrying of infants' corpses has been reported from a number of primate species, both in captivity and the wild [3-7] - albeit usually lasting a few days only - suggesting a phylogenetic continuity for a behavior that is poignant testament to the close mother-infant bond which extends across different primate taxa. In this report we recount two further infant deaths at Bossou, observed over a decade after the original episode but with striking similarities.

The evolution of laughter in great apes and humans

It has long been claimed that human emotional expressions, such as laughter, have evolved from nonhuman displays. The aim of the current study was to test this prediction by conducting acoustic and phylogenetic analyses based on the acoustics of tickle-induced vocalizations of orangutans, gorillas, chimpanzees, bonobos, and humans. Results revealed both important similarities and differences among the various species’ vocalizations, with the phylogenetic tree reconstructed based on these acoustic data matching the well-established genetic relationships of great apes and humans. These outcomes provide evidence of a common phylogenetic origin of tickle-induced vocalizations in these taxa, which can therefore be termed “laughter” across all five species. Results are consistent with the claims of phylogenetic continuity of emotional expressions. Together with observations made on the use of laughter in great apes and humans, findings of this study further indicate that there were two main periods of selection-driven evolutionary change in laughter within the Hominidae, to a smaller degree, among the great apes and, most distinctively, after the separation of hominins from the last common ancestor with chimpanzees and bonobos.

Behavioral and Neural Basis of Number Sense in Infancy

Approximate number discrimination in adult human and nonhuman animals is governed by Weber's Law: The ratio between the values determines discriminability. Here, we review recent evidence from behavioral and neuroimaging studies that suggests that number sense in human infancy shares the same hallmark feature of Weber's Law and may rely on the same neural substrates as previously found in adults, children, and nonhuman animals. These findings support the notion of ontogenetic and phylogenetic continuity in number sense. New methods described here may help uncover how infants' early number sense supports the development of a mature number sense. Moreover, they may aid in understanding how children learn to map nonsymbolic number representations onto symbols for number by providing dependent measures that capture individual variability.

Reconstructing the Evolution of Laughter in Great Apes and Humans

Human emotional expressions, such as laughter, are argued to have their origins in ancestral nonhuman primate displays. To test this hypothesis, the current work examined the acoustics of tickle-induced vocalizations from infant and juvenile orangutans, gorillas, chimpanzees, and bonobos, as well as tickle-induced laughter produced by human infants. Resulting acoustic data were then coded as character states and submitted to quantitative phylogenetic analysis. Acoustic outcomes revealed both important similarities and differences among the five species. Furthermore, phylogenetic trees reconstructed from the acoustic data matched the well-established trees based on comparative genetics. Taken together, the results provide strong evidence that tickling-induced laughter is homologous in great apes and humans and support the more general postulation of phylogenetic continuity from nonhuman displays to human emotional expressions. Findings also show that distinctively human laughter characteristics such as predominantly regular, stable voicing and consistently egressive airflow are nonetheless traceable to characteristics of shared ancestors with great apes.

Mitochondrial DNA Sequence Variation of the Swallowtail Butterfly, Papilio xuthus, and the Cabbage Butterfly, Pieris rapae

We analyzed a portion of mitochondrial COI gene sequences (658 bp) to investigate the genetic diversity and geographic variation of the swallowtail butterfly, Papilio xuthus L. (Lepidoptera: Papilionidae), and the cabbage butterfly, Pieris rapae L. (Lepidoptera: Pieridae). Papilio xuthus showed a moderate level of sequence divergence (0.91% at maximum) in 15 haplotypes, whereas Pi. rapae showed a moderate to high level of sequence divergence (1.67% at maximum) in 30 haplotypes, compared with other relevant studies. Analyses of population genetic structure showed that most populations are not genetically differentiated in both species. The distribution pattern of both species appears to be consistent with category IV of the phylogeographic pattern sensu Avise: a phylogenetic continuity, an absence of regional isolation of mtDNA clones, and extensive distribution of close clones. The observed pattern of genetic diversity and geographic variation of the two butterfly species seem to reflect the abundant habitats, abundant host plants, and flying abilities in connection with the lack of historical biogeographic barriers.

Merging of Phonological and Gestural Circuits in Early Language Evolution

In the monkey, cortical auditory projections subdivide into a dorsal stream mostly involved in spatiotemporal processing, that projects mainly to dorsal frontal areas; and a ventral stream involved in stimulus identification, connected to the ventrolateral prefrontal cortex (VLPFC). We propose that in the human lineage, part of the dorsal auditory pathway has specialized in vocalization processing, enhancing vocal repetition and short-term memory capacities that are crucial for linguistic development. In the human, the vocalization-related dorsal auditory component tends to converge in the VLPFC with the ventral auditory stream and with projections involved in gestural control; and consists of a direct connection between the auditory cortex and the VLPFC via the arcuate fasciculus, and an indirect pathway via the supramarginal gyrus. Additionally, intraparietal and inferior parietal afferents to the VLPFC are associated with communicative hand gestures, with manipulation skills and with early tool-making. Although in general terms compatible with the mirror-neuron gestural hypothesis for language origins, this proposal underlines the participation of the dorsal auditory pathway in voice processing as a key event that marked the beginning of human phonology and the subsequent evolution of language. Instead, the mirror neuron system for gestures and the primitive vocalization network (ventral pathway) contributed to provide a communicative scaffolding that facilitated the emergence of human-like phonology. Furthermore, we emphasize the phylogenetic continuity (homology) between non-human and human vocalization and their neural substrates, something that is not usually stressed in the mirror neuron perspective.

The Liang Bua faunal remains: a 95 k.yr. sequence from Flores, East Indonesia

Excavations at Liang Bua, a limestone cave on the island of Flores, East Indonesia, have yielded a well-dated archaeological and faunal sequence spanning the last 95 k.yr., major climatic fluctuations, and two human species – H. floresiensis from 95 to 17 k.yr. 1 1 Recent excavations at Liang Bua indicate that the disappearance of Homo floresiensis and Stegodon from the sequence coincided with a volcanic eruption ∼17 ka ago - not ∼12 ka as previously interpreted. , and modern humans from 11 k.yr. to the present. The faunal assemblage comprises well-preserved mammal, bird, reptile and mollusc remains, including examples of island gigantism in small mammals and the dwarfing of large taxa. Together with evidence from Early-Middle Pleistocene sites in the Soa Basin, it confirms the long-term isolation, impoverishment, and phylogenetic continuity of the Flores faunal community. The accumulation of Stegodon and Komodo dragon remains at the site in the Pleistocene is attributed to Homo floresiensis, while predatory birds, including an extinct species of owl, were largely responsible for the accumulation of the small vertebrates. The disappearance from the sequence of the two large-bodied, endemic mammals, Stegodon florensis insularis and Homo floresiensis, was associated with a volcanic eruption at 17 ka and precedes the earliest evidence for modern humans, who initiated use of mollusc and shell working, and began to introduce a range of exotic animals to the island. Faunal introductions during the Holocene included the Sulawesi warty pig ( Sus celebensis) at about 7 ka, followed by the Eurasian pig ( Sus scrofa), Long-tailed macaque, Javanese porcupine, and Masked palm civet at about 4 ka, and cattle, deer, and horse - possibly by the Portuguese within historic times. The Holocene sequence at the site also documents local faunal extinctions - a result of accelerating human population growth, habitat loss, and over-exploitation.

The role of source and filter cues in emotion recognition in speech

In the context of the source‐filter theory of speech, it is well established that intelligibility is heavily reliant on information carried by the filter, that is, spectral cues (e.g., Faulkner et al., 2001; Shannon et al., 1995). However, the extraction of other types of information in the speech signal, such as emotion and identity, is less well understood. In this study we investigated the extent to which emotion recognition in speech depends on filter‐dependent cues, using a forced‐choice emotion identification task at ten levels of noise‐vocoding ranging between one and 32 channels. In addition, participants performed a speech intelligibility task with the same stimuli. Our results indicate that compared to speech intelligibility, emotion recognition relies less on spectral information and more on cues typically signaled by source variations, such as voice pitch, voice quality, and intensity. We suggest that, while the reliance on spectral dynamics is likely a unique aspect of human speech, greater phylogenetic continuity across species may be found in the communication of affect in vocalizations.

Language in an Embodied Brain: the Role of Animal Models

The most parsimonious account of languageevolution is one where incremental, quantitativechanges in primates’ vocal tract, fiber pathways,and neuroanatomy converge with social andcultural developments. From this convergencearises the framework upon which complexlanguage skills could build. Such an ‘Emergentist’view emphasizes phylogenetic continuity in theneural substrates that mediate language, withlanguage processing embedded in systems withmore ancient sensorimotor roots. (Alternatively,‘Mental Organ’ theories – such as Chomsky, 1988– stress the discontinuity of language from all othermental/neural systems in humans and all otherspecies).Emergentist theories – as represented indevelopmental dynamical systems models,connectionism, cognitive linguistics, psychology,and cognitive neuroscience – emphasize the“embodied” or sensorimotor nature of brainorganization for higher cognitive functions.Following Piaget, complex cognitive operations(grammar, logic, mathematics) are viewed asneither innate nor learned; rather, they emerge(sometimes discontinuously) from interactionsbetween a sensorimotor brain and the constraints ofa complex problem space. Language is truly theproblem space

The use and abuse of developmental data

Structural similarity is helpful in recognizing homologous structures, but it does not define them. Such structures must also have phylogenetic continuity, a criterion that is ignored by Aboitiz et al. and by proponents of “field homology.” “Similar” structures, as well as “field homologues” from “the same” embryonic field, are not necessarily homologous, and an outgroup analysis of developmental stages should be performed to establish homologies.

Reading Morgan's Canon: Reduction and Unification in the Forging of a Science of the Mind1

Lloyd Morgan's advisory “Canon” on ascribing mental phenomena had an historically unusual and deep impact. It became a dictum defining true psychological science, praised for providing the foundation of a mature, hard science. Seen as a corrective to naive methodology and excessive speculation, it appeared to demand removal of mental qualities in the name of parsimony and rigor. Thus it is also disparaged for illegitimately limiting inquiry. Viewing Morgan's method and reasoning as the reactions of a Darwinian to the problems of psychology provides insight for a science of animal mind. The Canon should be seen as methodological advice for a science caught in the tensions between materialism and subjective mental experience, having to place human mind within phylogenetic continuity. Faced with irresolvable difficulties, behavioral science has oscillated between reduction and unifying integration, typical of debates over broad conceptual issues in evolutionary biology. The reasoning behind Morgan's Canon provides a strategy for balancing these twin pulls of scientific practice.

Antinociceptive effects of the neuroactive steroid, 3α-hydroxy-5α-pregnan-20-one and progesterone in the land snail, Cepaea nemoralis

Results of investigations with vertebrates have implicated neuroactive steroids and in particular 5α-reduced metabolites of progesterone such as 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP/3A5P and originally allopregnanolone) in the rapid modulation of diverse functions including that of nociceptive sensitivity. These effects have been indicated to involve modulation of GABA receptors. Results of recent phylogenetic studies have revealed the presence of GABA receptors in invertebrates that may also be subject to modulation by steroids and neuroactive steroids. The present study examined the effects of the neuroactive steroid, 3α-hydroxy-5α-pregnan-20-one, as well as progesterone on aversive thermal (nociceptive) responses in a mollusc, the land snail, Cepaea nemoralis. 3α-Hydroxy-5α-pregnan-20-one had significant dose-related (0.01–1.0 μg) antinociceptive effects in Cepaea increasing the latency of response to a 40°C surface, with maximum effects being evident 15–30 min after administration. These effects of 3α-hydroxy-5α-pregnan-20-one were stereospecific, with the stereoisomer 3β-hydroxy-5α-pregnan-20-one (3B5P) failing to affect nociceptive responses. Progesterone also had significant dose-related (0.10–10 μg) antinociceptive effects that, however, were delayed in onset and relatively prolonged (60–120 min), suggestive of the formation of active metabolites. The presence of endogenous progesterone (12.36±0.17 ng/g tissue) was ascertained by a radioimmunoassay further supporting a functional role for steroids in Cepaea. The antinociceptive effects of 3α-hydroxy-5α-pregnan-20-one and progesterone were blocked by the GABA antagonists, bicuculline and picrotoxin, while being relatively insensitive to opioid and N-methyl- d-aspartate antagonists. These results suggest an early evolutionary development and phylogenetic continuity of neuroactive steroid and GABA involvement in the mediation of nociception.

The ATD6-5 mandibular specimen from Gran Dolina (Atapuerca, Spain). Morphological study and phylogenetic implications

Metric and shape features of the Lower Pleistocene mandibular specimen ATD605 from the level 6 of Gran Dolina site (Atapuerca, Spain) are compared with a large sample of fossil hominid mandibles. The analysis shows that ATD6-5 displays a generalized morphology largely shared with both African and European Lower and Middle Pleistocene samples. However, distinctive African traits, such as corpus robustness and strong alveolar prominence, are absent in the Gran Dolina specimen. At the same time, none of the apomorphic features that characterize Middle and early Upper Pleistocene European hominids can be recognized in ATD6-5. Finally, the Gran Dolina specimen displays a remarkable position of the mylohyoid groove, only comparable to that found in immature specimens of Homo ergaster, and very rarely in adult H. sapiens. The morphology of ATD6-5 supports the hypothesis of an African origin for the first Europeans with subsequent phylogenetic continuity with Middle Pleistocene populations in Europe. These findings are consistent with H. antecessor being the last common ancestor of Neandertals and H. sapiens.

An immunocytochemical study of amelogenin proteins in the developing tooth enamel of the gar-pike, Lepisosteus oculatus (Holostei, Actinopterygii).

Previous studies have demonstrated the morphological similarity of the enamel-like layer found in the teeth of the coelacanth, lungfish and gar-pike to the enamel of tetrapods. In order to clarify the phylogenetic continuity between both structures, tooth germs of the gar-pike were immunocytochemically studied using an anti-bovine amelogenin polyclonal antibody. Intense immunoreaction was shown over the enamel-like matrix layer. Certain cell organelles associated with the secretory pathway of the ameloblasts were recognized as immunoreactive. These results indicate that the enamel-like layer of the gar-pike is a tissue homologous with the mammalian enamel because both possess a common, amelogenin-like substance.

Postcranial pneumatization in Archaeopteryx

Pneumatization of the postcranial skeleton by the lungs is thought to be a hallmark of the avian skeleton, and to be an adaptation for flight by reducing weight. Pneumatic features have, however, remained elusive in the primitive avialan Archaeopteryx lithographica. The hollow long bones of Archaeopteryx were first interpreted to be pneumatized1, but this interpretation was later rejected because of an absence of pneumatic foramina in these bones that connect their interiors with the respiratory system2,3,4,5,6. Pneumatic features have also been recognized in the axial skeleton of many non-avialan theropod dinosaurs (and some other archosaurs of the bird clade). The purported lack of postcranial pneumatic features in Archaeopteryx has been interpreted as a primitive condition of avialans; this raises doubts about the homology between postcranial pneumatic features of birds and non-avialan theropods7. Here we re-examine two specimens of Archaeopteryx. These specimens show evidence of vertebral pneumaticity in the cervical and anterior thoracic vertebrae, thus confirming the phylogenetic continuity between the pneumatic systems of non-avialan theropods and living birds.

Intraspecific genetic structure of white sucker (Catostomus commersoni) in northeastern North America as revealed by mitochondrial DNA polymorphism

Restriction fragment length polymorphisms in mitochondrial DNA (mtDNA) were used to study the influence of Pleistocene glaciations on the intraspecific genetic structure and distribution of the white sucker (Catostomus commersoni) in northeastern North America. A total of 312 white sucker from 13 populations, including a population of dwarf ecotypes (Catostomus commersoni utawana), were analysed. An average of 93 fragments per individual and 40 haplotypes were generated by nine restriction endonucleases. Four discrete clades were identified but the majority of the genotypes found (70%) were not associated with any of the clades. The phylogenetic continuity and the geographic admixture of some of the few clades identified are associated with the extensive distribution of the species south of the ice sheets during Pleistocene glaciation events. Hierarchical analysis of the variability in mtDNA revealed a significant regional subdivision to the northwest and southeast of the St. Lawrence drainage system and significant structure at the population level. As the dwarf form exhibited a haplotype identical to that found among normal forms, we tentatively conclude sympatric divergence as the most likely origin of the dwarf and normal ecotypes sampled in the Adirondacks.

The NMDA Receptor Antagonist, NPC 12626, Reduces the Pronociceptive Effects of Orphanin FQ and Kappa Opiate Antinociception in the Land Snail, Cepaea nemoralis

KAVALIERS, M., E. CHOLERIS AND D. M. SAUCIER.The NMDA receptor antagonist, NPC 12626, reduces the pronociceptive effects of orphanin FQ, and kappa opiate antinociception in the land snail, Cepaea nemoralis. PEPTIDES 18(7) 943–947, 1997.—The heptadecapeptide, orphanin FQ or nociceptin (Phe-Gly-Phe-Thr-Gly-Ala-Arg-Lys-Ser-Ala-Arg-Lys-Leu-Ala-Asn-Gln), originally isolated from rat brain has been identified as an endogenous ligand for the orphan opioid-like receptor. Although orphanin FQ shares some sequence and structural homology with kappa-opioid peptides, it has been speculated to exert its effects through novel nonopioid mechanisms. Kappa opioids have also been suggested to have nonopioid actions in rodents involving the N-methyl-D-aspartate (NMDA) receptor. The present study examined the effects of the competitive NMDA antagonist, NPC 12626, on the antinociceptive effects of the specific kappa-opiate receptor agonist, U69,593, and the pronociceptive effects of orphanin FQ in an invertebrate system, the land snail, Cepaea nemoralis. NPC 12626 had no effect on the basal nociceptive sensitivity of snails, as measured by the latency of response to a thermal (40°C) surface. As reported for rodents, NPC 12626 dose-dependently reduced U69,593-induced antinociception in a manner comparable to that produced by the specific kappa-opiate antagonist, nor-binaltorphimine, while slightly enhancing the antinociceptive effects of the predominately mu-opiate agonist, morphine. Similarly, NPC 12626 dose-dependently reduced the pronociceptive effects of orphanin FQ. These findings with the snail, Cepaea, indicate that NMDA systems/receptors are associated with the mediation of the nociceptive effects of both kappa opioids and orphanin FQ. They suggest an early evolutionary development and phylogenetic continuity of NMDA opioid and related neuropeptide interactions in the mediation of nociception.

A late Neanderthal associated with Upper Palaeolithic artefacts

The French site of Arcy-sur-Cure is a key locality in documenting the Middle-Upper Palaeolithic transition in Europe. Reliable attribution of the fragmentary hominid fossils associated with its early Upper Palaeolithic Châtelperronian industry has not been possible. Here we report the first conclusive identification of one of these fossils as Neanderthal on the basis of newly discovered derived features of the bony labyrinth. Dated at about thirty-four thousand years (34 kyr) ago, the fossil is representative of the youngest known Neanderthal populations, and its archaeological context indicates that these hominids used a rich bone industry as well as personal ornaments. The evidence supports the hypothesis of a long term coexistence with technocultural interactions between the first modern humans and the last Neanderthals in Europe. However, the complete absence of the derived Neanderthal traits in labyrinths of modern Upper Palaeolithic specimens from western Europe argues against phylogenetic continuity between the two populations in this region.