On the probability of ancestors in the fossil record

Paleobiology ◽  
1996 ◽  
Vol 22 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Mike Foote

Three homogeneous models of species origination and extinction are used to assess the probability that ancestor-descendant pairs are preserved in the fossil record. In the model of cladogenetic budding, a species can persist after it branches and can therefore have multiple direct descendants. In the bifurcation model, a species branches to give rise to two distinct direct descendants, itself terminating in the process. In the model of phyletic transformation, a species gives rise to a single direct descendant without branching, itself terminating in the process. Assuming homogeneous preservation, even under pessimistic assumptions regarding the completeness of the fossil record, the probability of finding fossil ancestor-descendant pairs is not negligible. Even if all species of Phanerozoic marine invertebrates in the paleontologically important taxa had the same probability of preservation, on the order of 1%-10% or more of the known fossil species would be directly ancestral to other known fossil species. However, this is likely to be an underestimate, since the probability of finding ancestor-descendant pairs is enhanced by taxonomic, temporal, and spatial heterogeneities in preservation probability. Moreover, indirect genealogical relationships substantially increase the probability of finding ancestor-descendant pairs. The model of budding, the only one in which an ancestor can persist after a branching event, predicts that half or more of extant species have ancestors that are also extant. Thus, the question of how to recognize ancestor-descendant pairs must be carefully considered.

2017 ◽  
Vol 284 (1866) ◽  
pp. 20171771 ◽  
Author(s):  
Dahiana Arcila ◽  
James C. Tyler

Integrative evolutionary analyses based upon fossil and extant species provide a powerful approach for understanding past diversification events and for assessing the tempo of evolution across the Tree of Life. Herein, we demonstrate the importance of integrating fossil and extant species for inferring patterns of lineage diversification that would otherwise be masked in analyses that examine only one source of evidence. We infer the phylogeny and macroevolutionary history of the Tetraodontiformes (triggerfishes, pufferfishes and allies), a group with one of the most extensive fossil records among fishes. Our analyses combine molecular and morphological data, based on an expanded matrix that adds newly coded fossil species and character states. Beyond confidently resolving the relationships and divergence times of tetraodontiforms, our diversification analyses detect a major mass-extinction event during the Palaeocene–Eocene Thermal Maximum (PETM), followed by a marked increase in speciation rates. This pattern is consistently obtained when fossil and extant species are integrated, whereas examination of the fossil occurrences alone failed to detect major diversification changes during the PETM. When taking into account non-homogeneous models, our analyses also detect a rapid lineage diversification increase in one of the groups (tetraodontoids) during the middle Miocene, which is considered a key period in the evolution of reef fishes associated with trophic changes and ecological opportunity. In summary, our analyses show distinct diversification dynamics estimated from phylogenies and the fossil record, suggesting that different episodes shaped the evolution of tetraodontiforms during the Cenozoic.


Zootaxa ◽  
2019 ◽  
Vol 4658 (1) ◽  
pp. 37-68
Author(s):  
LAURA NICOLI

Ceratophrys is the most diverse and widely distributed genus of Ceratophryidae, the clade of South American horned frogs. Numerous anuran fossil remains, including several fossil species, have been assigned to this genus. However, this seemingly extensive fossil record is problematic because several of the fossils are not properly identified and most of the taxonomic assignations are not justified. The present study traces all the fossil material attributed to Ceratophrys, clarifying, when possible, institutional allocations. Each of the remains was examined and its taxonomic assignation revisited, based on the morphology and possible synapomorphies of the genus, including its living species. Numerous fossils were properly identified and assigned with certainty to Ceratophrys. Only one fossil species, Ceratophrys ameghinorum, is considered valid. This information, along with recently reported evidence of fossil Ceratophrys, is briefly summarized to serve as a practical reference for the entire known fossil record of the genus. The fossil record is not especially informative about the evolution or distribution pattern of Ceratophrys, because most of the remains are relatively young (post-Miocene), collected within the present distribution of the genus, and morphologically consistent with that of the extant species. However, some useful information has emerged. The presence of Ceratophrys is well documented since the Neogene in the Pampean Region of South America. The single valid fossil species, Ceratophrys ameghinorum, possesses a unique combination of characters that reflects a mixture of characters observed in different clades of the genus; thus, resolution of its phylogentic position will inform our understanding of the evolution of the genus. The paleoenvironmental significance of some Ceratophrys fossils is also discussed, addressing the wide, but incompletely known current distribution and environmental tolerance of the genus.


2020 ◽  
Vol 635 ◽  
pp. 71-79 ◽  
Author(s):  
M Pagès-Escolà ◽  
PE Bock ◽  
DP Gordon ◽  
S Wilson ◽  
C Linares ◽  
...  

The number of species that exist on Earth has been an intriguing question in ecology and evolution. For marine species, previous works have analysed trends in the discovery of extant species, without comparison to the fossil record. Here, we compared the rate of description between extant and fossil species of the same group of marine invertebrates, Bryozoa. There are nearly 3 times as many described fossil species as there are extant species. This indicates that current biodiversity represents only a small proportion of Earth’s past biodiversity, at least for Bryozoa. Despite these differences, our results showed similar trends in the description of new species between extant and fossil groups. There has been an increase in taxonomic effort during the past century, characterized by an increase in the number of taxonomists, but no change in their relative productivity (i.e. similar proportions of authors described most species). The 20th century had the most species described per author, reflecting increased effort in exploration and technological developments. Despite this progress, future projections in the discovery of bryozoan species predict that around 10 and 20% more fossil and extant species than named species, respectively, will be discovered by 2100, representing 2430 and 1350 more fossil and extant species, respectively. This highlights the continued need for both new species descriptions and taxonomic revisions, as well as ecological and biogeographical research, to better understand the biodiversity of Bryozoa.


2019 ◽  
Vol 2 (5) ◽  
pp. 505-514 ◽  
Author(s):  
DAVID PERIS ◽  
JOSEF JELÍNEK

Although the family Kateretidae has fewer than 100 described extant species, its fossil record is growing. The description given here of Electrumeretes birmanicus gen. et sp. nov. and Polliniretes penalveri gen. et sp. nov. brings the number of fossil species in Kateretidae up to nine. Eight of the fossil species have been described from amber deposits and six are from the Cretaceous. All the Cretaceous fossil species and one from the Eocene share atypically short elytra and three dorsally exposed abdominal tergites, whereas in Recent relatives, even though they have shortened elytra, only the pygidium and a part of the preceding one or two abdominal tergites are exposed. It is suggested that shortened elytra (brachelytry) represents an ancestral state and that elytra may have become secondary longer in extant relatives.


Zootaxa ◽  
2018 ◽  
Vol 4407 (3) ◽  
pp. 443 ◽  
Author(s):  
JUAN FRANCISCO ARAYA ◽  
MARIA ALEKSANDRA BITNER

Phylum Brachiopoda, shelled marine invertebrates, is currently represented by about 400 extant species; a tiny fraction of the ca. 30,000 described fossil species (Emig et al. 2013; Bitner 2014; Nauendorf et al. 2014; Logan et al. 2015). Only twenty of these Recent species are known from the Chilean coasts (Lee et al. 2008), most of them from subtidal waters. Of these, only Magellania venosa (Dixon, 1789) (the largest extant brachiopod) and Discinisca lamellosa (Broderip, 1833) are common species found in the southern and central-northern coasts of the country, respectively. As with other marine invertebrates, brachiopods from the region have been reviewed in few studies, apart from some classic nineteenth century works by Sowerby (1822); Broderip (1833); Davidson (1878, 1888); Dall (1895, 1902, 1908), and by Dall and Pilsbry (1891). More recent studies include Cooper (1973, 1982) and Foster (1989) reviewing brachiopods from the Southern Hemisphere and the extreme South Pacific; Zezina (1981, 1989) describing species from the underwater ridges of the Eastern Pacific; Moyano (1995) who revised all the literature dealing with Brachiopoda in Chile; and most recently Baumgarten et al. (2014) who studied the population structure of Magellania venosa in the fjord region of southern Chile. 


Phytotaxa ◽  
2021 ◽  
Vol 513 (1) ◽  
Author(s):  
EDOARDO MARTINETTO ◽  
NICOLA M. G. ARDENGHI ◽  
DANIELE AROBBA ◽  
ADELE BERTINI ◽  
GIOVANNA BOSI ◽  
...  

Lycopus is a widespread herbaceous plant, currently part of European flora. Fossil remains of fruits (nutlets or mericarps) attributed to this genus are frequently found in European archaeological and palaeontological sites, being easily preserved in sedimentary deposits. In a worldwide context, the oldest fossils are from the early Oligocene (ca. 30 Ma) of West Siberia, but they become more common in Miocene (23.0–5.3 Ma) records, ranging from West Siberia to Central Europe. In the literature, the Oligocene and Miocene remains (plus a few Pliocene ones) were assigned to fossil-species, whereas the abundant Pliocene and Pleistocene occurrences (5–0.01 Ma) in Europe were mainly assigned to the extant species L. europaeus. The present work is conceived as the result of an ad hoc research team whose task was to revise and summarize the Italian fossil record of Lycopus, assembling palaeobotanical and archaeobotanical data. We herein report ca. 6000 Lycopus nutlets from 61 sites located in nine regions of Northern and Central Italy. Based on the available information on extant species, we detected nine morphological types of nutlets that can be used for the characterisation of fossils. Our analysis suggests that from 4 to 2.6 Ma a single taxon (L. cf. pliocenicus) with L. americanus-type of nutlets occurred in Italy. The first occurrence of the latter morphological type is from the early Oligocene of West Siberia. The available fossils mildly suggest that extant L. americanus could be the descendant of ancient Eurasian plants characterised by the L. americanus-type of nutlets, through expansion of their range to North America. Conversely, the abundant Italian records of the last 0.2 Ma, including remains from archaeological sites, are only referable to the Eurasian species L. europaeus.


Zootaxa ◽  
2009 ◽  
Vol 2026 (1) ◽  
pp. 33-39 ◽  
Author(s):  
ANTONIO ARILLO ◽  
ENRIQUE PEÑALVER ◽  
VICTORIA GARCÍA-GIMENO

In this paper Litoleptis fossilis sp. nov. a new fossil species belonging to the family Spaniidae (Diptera) is described. This is the first time the genus Litoleptis has been described from the fossil record. A comparison with extant species of Litoleptis and other fossil rhagionoids is done. The fossil is also compared to not closely related Diptera but having convergent wing venation. Palaeoecological and palaeobiogeographical comments are provided.


2008 ◽  
Vol 82 (2) ◽  
pp. 436-441 ◽  
Author(s):  
Raef Minwer-Barakat ◽  
Antonio García-Alix ◽  
Elvira Martín-Suárez ◽  
Matthijs Freudenthal

The Genus Micromys includes a single extant species, Micromys minutus (Pallas, 1771), which lives in Europe and North Asia. This genus is known in the fossil record since the late Miocene; eight fossil species have been described in Europe and Asia, most of them of late Miocene and early Pliocene age. The evolution of this genus during the late Pliocene is barely known. Although it is present in numerous localities of this age, remains of Micromys are usually scarce and generally assigned to the species M. minutus or M. praeminutus Kretzoi, 1959.


Zootaxa ◽  
2019 ◽  
Vol 4550 (4) ◽  
pp. 565 ◽  
Author(s):  
ANDRIS BUKEJS ◽  
VITALII I. ALEKSEEV ◽  
DAVID M.L. COOPER ◽  
GAVIN A. KING ◽  
RYAN C. MCKELLAR

Based on a well-preserved specimen from Eocene Baltic amber, the second fossil species belonging to the genus Pycnomerus Erichson (Coleoptera: Zopheridae: Zopherinae), P. agtsteinicus Bukejs, Alekseev & McKellar sp. nov. is described and illustrated using synchrotron X-ray micro-CT observations. The new species adds to the sparse fossil record of Pycnomerus, which consists of the Baltic amber discoveries, and only four subfossil records in sediments that are less than one million years old. As part of this work, the new replacement name Pycnomerus lordi Bukejs, Alekseev & McKellar nom. nov. is also established for the extant species Pycnomerus sulcicollis LeConte, 1863 [non Pycnomerus sulcicollis (Germar, 1824)]. 


2017 ◽  
Vol 92 (2) ◽  
pp. 170-182 ◽  
Author(s):  
Dale Tshudy ◽  
Matúš Hyžný ◽  
Alfréd Dulai ◽  
John W.M. Jagt

AbstractThe fossil record of the clawed lobster genus,Homarus, is appraised. The taxonomic history ofHomarusandHoplopariais summarized, and a list of species recognized for each is provided. A tabulation of all fossil species of the family Nephropidae permits assessment of nephropid species diversity through time. A new species ofHomarus,H.hungaricus, is recorded from the upper Oligocene (Chattian) Mány Formation at Mány, northern Hungary. The species is known by a single specimen consisting of a partial cephalothorax, a pleon minus telson, and partial chelipeds.Homarusis now known by two extant species (H.americanusandH.gammarus) and six fossil taxa, one of Early Cretaceous (Albian;H.benedeni) and five of Cenozoic age (H.hungaricusn. sp.,H.klebsi,H.lehmanni,H.morrisi, andH.percyi). The new fossilHomarusdiffers from modern congeners in aspects of carapace and pleon ornamentation and, especially, cutter claw shape. This is the fourth Oligocene occurrence of a nephropid species; all areHomarusand all are from Western Europe.Homarusmakes its appearance in the fossil record in the Early Cretaceous (Albian) and then is not known again until the Paleogene, despite the fact that nephropid lobsters in general are well known from the Late Cretaceous. Nephropid lobsters are better known from the Cretaceous than from the Cenozoic. Both raw species numbers and numbers corrected (normalized) for epicontinental sea coverage show that shelf-dwelling nephropid lobsters were most diverse during the Late Cretaceous.


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