Ghost lineage
A ghost lineage is a hypothesized ancestor in a species lineage that has left no fossil evidence, but can still be inferred to exist or have existed because of gaps in the fossil record or genomic evidence.[1][2] The process of determining a ghost lineage relies on fossilized evidence before and after the hypothetical existence of the lineage and extrapolating relationships between organisms based on phylogenetic analysis.[3] Ghost lineages assume unseen diversity in the fossil record and serve as predictions for what the fossil record could eventually yield; these hypotheses can be tested by unearthing new fossils or running phylogenetic analyses.[4]
Ghost lineages and Lazarus taxa are related concepts, as both stem from gaps in the fossil record.[2] A ghost lineage is any gap in a taxon's fossil record, with or without reappearance, while a Lazarus taxon is a type of ghost lineage wherein a species is believed to have gone extinct due to an absence of it in the fossil record, but then reappears after a period of time.[2] Examples of Lazarus taxa include the famous coelacanths, as well as the Philippine naked-backed fruit bat.[5]
Name
In 1992, an article stated: "These additional entities are taxa [groups] that are predicted to occur by the internal branching structure of
It is important to note that ghost lineages and ghost taxa are not the same. A ghost lineage is a one direct connection between the descendant and the ancestor, whereas a ghost taxon has many split descendants.[3]
Examples
When looking back at extinct organisms, there are some groups of organisms (or lineages) that have gaps in their fossil records. These organisms or species may be closely related to one another, but there are no traces in the fossil records or sediment beds that might shed some light on their origins. Biologists may infer the existence of ghost lineages by examining sequential stratigraphic units in the fossil record.
Duration and diversification
The duration between distinct fossils can be measured and used to derive information about the evolutionary history of a species. A study conducted in 1998 showed that a correlation exists between the diversification of a species and the duration of its ghost lineage; namely that a shorter ghost lineage implies that there will be greater species diversification.[10]
Genetic evidence
Genetic evidence has revealed ghost populations in many species, including modern bonobos and chimpanzees,
See also
References
- PMID 31023378.
- ^ a b c d Wedel M (May 2010). "Ghost lineages". University of California Museum of Paleontology. Retrieved November 4, 2019.
- ^ .
- ^ Dingus L, Rowe T (1998). The Mistaken Extinction: Dinosaur Evolution and the Origin of Birds. New York: W. H. Freeman.
- ^ Gentle L. "Meet the Lazarus creatures – six species we thought were extinct, but aren't". The Conversation. Retrieved 2019-12-04.
- ^ Norell MA (1992). Novacek MJ, Wheeler QD (eds.). Taxic Origin and Temporal Diversity: The Effect of Phylogeny, in Extinction and Phylogeny. Columbia University Press, New York. pp. 89–118.
- S2CID 26752987.
- ^ PMID 17652067.
- PMID 26064540.
- S2CID 83773704.
- ^ S2CID 139107044.
- PMID 30894575.
- ^ a b "New Branch Added to European Family Tree". Harvard Medical School. Retrieved 2019-12-11.