16 Jan 2018: Rivadeneira MM, Nielsen SN (2018) Correction: Diversification dynamics, species sorting, and changes in the functional diversity of marine benthic gastropods during the Pliocene-Quaternary at temperate western South America. PLOS ONE 13(1): e0191525. https://doi.org/10.1371/journal.pone.0191525 View correction
Functional diversity based on species traits is a powerful tool to investigate how changes in species richness and composition affect ecosystem functioning. However, studies aimed at understanding changes in functional diversity over large temporal and spatial scales are still scant. Here we evaluate the combined effect of diversification and species sorting on functional diversity of fossil marine gastropods during the Pliocene-Quaternary transition in the Pacific coast of South America. We analyzed a total of 172 species in 29 Pliocene and 97 Quaternary sites. Each species was characterized according to six functional traits: body size, feeding type, mobility, attachment, life-habit, and larval mode. Functional diversity was estimated according to four indexes (functional richness, evenness, divergence and dispersion) based on functional traits measured. Extrapolated species richness showed a slight yet not significant decrease from the Pliocene to the Quaternary despite the fact that a large faunal turnover took place; furthermore, a large extinction of Pliocene species (61–76%) was followed by a high pulse of appearances (49–56%) during the Quaternary. Three out of four indices of functional diversity (evenness, divergence and dispersion) increased significantly towards the Quaternary which is more than expected under a random turnover of species. The increase in functional diversity is associated with a loss of large-sized carnivore forms, which tended to be replaced by small-sized grazers. Hence, this trait-selective species turnover, even in the absence of significant changes in species richness, likely had a large effect and has shaped the functional diversity of present-day assemblages.
Citation: Rivadeneira MM, Nielsen SN (2017) Diversification dynamics, species sorting, and changes in the functional diversity of marine benthic gastropods during the Pliocene-Quaternary at temperate western South America. PLoS ONE 12(10): e0187140. https://doi.org/10.1371/journal.pone.0187140
Editor: Geerat J. Vermeij, University of California, UNITED STATES
Received: February 27, 2017; Accepted: October 13, 2017; Published: October 26, 2017
Copyright: © 2017 Rivadeneira, Nielsen. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: This work was funded by FONDECYT projects 1140841, 1150664 and INACH G_05-11. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
The current threats to global biodiversity have increased the need to understand the role of species diversity on ecosystem functioning [1–4]. While the importance of species richness on ecosystem functioning has been demonstrated experimentally [3, 5, 6], its application across very large scales is impractical, limiting the generality of conclusions. A simple yet powerful approach to understand ecosystem functioning is through the concept of functional diversity (FD hereafter). FD measures “functional trait diversity, where functional traits are components of an organism’s phenotype that influence ecosystem level processes” . A large body of literature has focused on theoretical or methodological aspects of FD analyses [7–11].
Unlike spatial patterns of variation in FD that have been increasingly studied in multiple taxa and systems [12–14], patterns of temporal variation are much less understood or have been documented over shorter timescales at small spatial scales . The fossil record provides an excellent arena for the study of temporal variation in FD at much larger timescales and over larger spatial scales [15, 16]. Temporal changes in FD at evolutionary timescales can occur due to shifts in species richness (due to differential origination/extinction/dispersal rates) or species composition (due to species sorting). Species sorting (or species selection) refers to the preferential persistence of species according to the interaction between their intrinsic traits and the environment . Therefore, non-random extinctions or originations may have important effects on FD, especially if the redundancy of the system is low [4, 8, 18]. Vast volumes of paleontological studies have documented the existence of species sorting in marine taxa [17, 19]. The selectivity of other traits seems sensitive to extinction intensity; for instance, a long list of different factors—including local abundance, reproductive mode, body size, trophic strategy, and life habit—were not selective at genus level during the K/Pg mass extinction [20, 21]. However, many of these factors have shown high selectivity during background extinction times or large extinctions at regional scales [22–24]. Whether the diversification trends and species sorting is translated into changes in FD remains much less studied [15, 16].
The Pliocene-Quaternary mollusc turnover provides an interesting temporal frame to evaluate these ideas. This faunal turnover, characterized by enhanced extinction and origination rates, affected different regions around the globe with variable intensity [22, 25–29] and was associated with major climatic and oceanographic generalized re-organization (e.g. cooling and changes in marine productivity) . The impact of these transformations is well illustrated along the temperate coast of western South America where for more than a century a large Plio- Quaternary marine faunal turnover has been described  which altered the standing species richness and biogeographic patterns of several taxa [22, 32, 33]. If the faunal turnover was also selective for the ecological and life-history traits of these species, as shown in bivalves  and vertebrates , then an evolutionary change in the FD should be expected—a possibility that remains untested. Here we test these ideas, using benthic gastropods, a diverse and well-documented group with an excellent fossil record in the region [32, 34], as a study model. Our goals were: a) to quantify the magnitude of the Pliocene-Quaternary turnover in marine benthic gastropods along western South America, and b) to determine the impact of species sorting during the Pliocene-Quaternary turnover on the functional diversity of gastropod assemblages.
Materials and methods
We gathered a database documenting the occurrence of 172 gastropod species from 126 fossiliferous sites (29 Pliocene, 97 Quaternary) along the temperate Pacific coast of South America from northern Peru to southern Chile. Although the paleoenvironments have been little studied, the environments represent shallow-water habitats (i.e., coastal shelf) in wave-exposed and wave-protected areas [34–36]. A total of 1,553 occurrences were compiled (see S1 Table). The information was collected from our own field studies and complemented with an exhaustive literature search [32, 37–58]. For each species, we gathered information about the body size (maximum shell length), locomotion (actively mobile, facultative mobile, slow-moving), attachment (attached, non-attached), life-habit (epifaunal, infaunal), feeding type (carnivore, grazer, suspension feeder), and larval mode (aplanktonic, planktonic feeding, planktonic non-feeding). Maximum shell length and larval mode were obtained from our own collections and observations and complemented with information from literature (see above and Supplemental information). Information for locomotion, attachment, life-habit and feeding type was gathered from Paleobiology Database (https://paleobiodb.org/), and its use has been validated by previous studies [59–61]. If information was not available for a given species, traits were inferred or generalized from species belonging to the same genus or family, given that ecological and life-history traits are often phylogenetically conserved [12, 62]. The relationship among these ecological and life history traits is not orthogonal (i.e. not all the combinations of these factors are observed/possible) because some traits are correlated in part. For instance, carnivores are typically mobile forms and tend to be large-sized. However, this possible multi-collinearity effect is properly addressed by functional diversity analyses (see below). The database of species occurrences and functional traits used in our analyses are provided in the supporting information (S1 and S2 Tables).
We evaluated the intensity of the Pliocene-Quaternary turnover, quantifying the standing species richness and the intensity of extinction and appearance of new forms. To evaluate the standing species richness in Pliocene and Quaternary assemblages we used the non-parametric extrapolation Chao 2 index  based on species-sites presence-absence matrices. We also estimated the species richness at a local scale using a subset of sites for which abundance (number of individuals per species) was available, using the Chao 1 index . Analyses were carried out in the library vegan in R . Species extinction was estimated as the percentage of Pliocene species not found during the Quaternary; conversely, species appearance was estimated as the percentage of Quaternary species making a first appearance during the Quaternary. These estimates, however, assume that sampling effort was similar between Pliocene and Quaternary, which clearly is not the case. In order to account for this possible bias, we re-estimated the Chao 2 index, extinction, and appearance using similar sampling effort for Pliocene and Quaternary assemblages (n = 29 sites in 10,000 runs).
Temporal changes in the prevalence of the six functional traits were evaluated using t-tests and χ2 tests. We estimated the importance of taxonomic selectivity for both extinction and apparition of taxa by comparing the observed proportion of families that went extinct and appeared with the expectations of a random null model which assumed that the faunal turnover was independent of the taxonomic identity of the species (10,000 runs).
All six functional traits were used to evaluate changes in the functional diversity and were characterized through four complementary metrics: a) functional richness (FRic), b) functional evenness (FEve), c) functional divergence (FDiv), and d) functional dispersion (FDis). These four metrics emphasize different aspects of the functional diversity of assemblages [15, 66]. FRic, FEve and FDiv are based on principal coordinates analyses which are based on a dissimilarity matrix built on Gower’s index . FRic is measured as the convex hull volume of the multivariate trait space, where higher values indicate a larger functional space. FEve is measured as the minimum spanning tree linking all the species within the trait space, where high values of FEve imply a more regular filling of the functional space . FDiv measures the species deviance from the centroid of the multivariate trait space, and it is higher if species are far from the centroid, implying the existence of more extreme trait values in the functional space . FDis is the average distance to the centroid of the multivariate trait space, where higher values indicate a higher dispersion of species over the trait space . Importantly, FD indices are not affected by the possible multi-collinearity among functional traits; indeed, the principal coordinate analysis transforms a number of correlated variables into a reduced subset of uncorrelated variables (PCO axes). We pooled species across all sites in Pliocene and Quaternary assemblages and estimated FD indices for each time bin. We estimated the change in FD according to each metric for: i) the Pliocene extinction (Pliocene FD—extinct species FD), ii) Quaternary appearance (appearing species FD- surviving species FD), and iii) between the Quaternary and Pliocene. We tested whether the change in each FD metric was different than expected under a null model of random species turnover by re-shuffling the species identity in the matrix of traits (10,000 runs). Analyses were carried out using the library FD  and scripts written in R .
The extrapolated species richness (Chao 2 index) increased with sampling effort (number of sites) in both Pliocene and Quaternary assemblages, showing no sign of saturation (Fig 1A). The observed Pliocene species richness (99) represents 61% (95% CI: 47–85%) of true “discoverable” richness. For Quaternary assemblages, the observed species richness (115) represents ca. 59% of the discoverable pool of species (95% CI: 42–97%). For a similar sampling effort, Pliocene assemblages showed a slightly higher extrapolated species richness, but this difference was not significant (Fig 1A). At a local scale, mean extrapolated richness (Chao 1 index) was not significantly different between Pliocene (median = 18 species, 7 sites) and Quaternary (median = 15 species, 31 sites) assemblages (t test, t = -1.11, P = 0.28). Face-value estimates show that 59% of species (95% CI: 47–67%; 57 out of 99 species) went extinct, and 63% (95% CI: 53–71%; 73 out of 117 species) originated during the Pliocene-Quaternary transition. When differences in sampling intensity were controlled, trends reversed (Fig 1B), showing higher extinction levels (95% CI: 61–76%) than appearance (95% CI: 49–66%).
(A) Extrapolated species richness (Chao 2 index) versus sampling effort (sampled sites) for 29 Pliocene and 97 Quaternary sites. 95% CI are shown by lines. (B) Bias-corrected estimate of the Pliocene extinction and Quaternary apparition of species. Frequency distributions based on 10,000 resampled values with a similar sampling effort in Pliocene and Quaternary deposits (n = 29 sites).
The prevalence of different ecological traits was variable in time (Fig 2). There was a significant reduction in the body size of species from the Pliocene (median = 40 mm) to the Quaternary (median = 29 mm) (t-test on log-transformed data, P = 0.007, Fig 2A). The prevalence of feeding types also experienced changes, particularly a reduction in the proportion of carnivores (from 65% to 46%) and an increase in the herbivore grazers (from 25% to 41%) (Fig 2E). For other traits, no significant changes were detected (χ2 test, P > 0.05, Fig 2).
(A) body size, (B) mobility, (C) attachment, (D) life habit, (E) feeding, and (F) larval mode. The significance of changes is indicated by p-values (t-test for body size, χ2 test for other traits).
Neither the extinction nor the apparition of species was taxonomically selective, as the proportion of extinct/appearing families was not different than expected by the null model (Fig 3). Patterns were, in general, similar within the most speciose families (Table 1). For instance, in Muricidae—the most speciose family during both Pliocene and Quaternary—the observed proportion of extinct species (0.64, 23 out of 36) was not different than expected by chance (95% CI: 0.41–0.74). However, the proportion of appearing Muricidae during the Quaternary (0.38, 8 out of 21) was lower than expected by the null model (95% CI: 0.48–0.79).
Observed proportion of extinct (A) and appearing families (B) versus the expected values under a null model assuming a taxonomically random species turnover (10,000 runs).
The four metrics of functional diversity, depicted by the two first axes of a principal coordinate analysis, showed an increase from the Pliocene to the Quaternary (Fig 4), revealing changes in functional evenness, divergence and disparity, which was significantly higher than expected under a random null model of a trait-independent diversification (P < 0.05, Table 2). The Pliocene extinction produced a significant increase in all indices, except in the case of functional richness (Table 2). The Quaternary appearance of species also increased the functional divergence (P = 0.03), but the change for other indices were non-significant (Table 2).
(A-B) FRic: functional richness; (C-D) FEve: functional evenness; (E-F) FDiv: functional divergence; (G-H) FDis: functional dispersion). Each species is represented in a bivariate space created by the two first axes of a principal coordinate analysis (PCO) (see also Table 2).
Our results show the FD of benthic gastropod assemblages along the western South America, indicating important changes during the Pliocene-Quaternary transition coupled with a large species turnover. Despite this species richness remaining relatively similar across time, the trait-selective replacement of a large number of taxa had a marked impact on the FD of gastropods.
The existence of a large faunal turnover during the Pliocene-Quaternary transition at western South America has been hypothesized for more than a century [31, 68]. Our results show the existence of a massive removal of species—confirming preliminary evaluations [51, 53, 56]—followed by the appearance of many new forms. These trends seem robust to differences in sampling intensity between the Pliocene and Quaternary and to the completeness of fossil inventories. Similarly, higher levels of biotic turnover have been estimated for bivalves and marine vertebrates . The ultimate causes of the turnover are likely related to the onset of the modern conditions of the Humboldt Current and include several mutually non-exclusive factors, including a drastic decrease in sea temperature [69, 70], increasing primary productivity , destruction of wave-sheltered coastal habitats due to tectonic subsidence [34, 72], increasing anoxia due to increasing primary productivity , and habitat destruction and creation implied by the advance/retreat of glacial lobes in southern Chile during glacial/interglacial cycles . Thus, the same factors promoting the disappearance of many forms also acted as drivers for the appearance of new species. The rapid appearance of new forms during the Quaternary has also been inferred based on phylogenetic analyses .
Evidence from the fossil record has shown drastic changes in FD through events of major biotic turnover , but patterns are hard to compare given the many methodological approaches used to assess patterns of functional diversity [75, 76]. Different FD trends can be inferred according to different methodological approaches [16, 77, 78]. Indeed, our analyses reveal that changes in FD can be inferred based on three out of four metrics. The functional richness index, sensitive to changes in species richness , increased slightly towards the Quaternary; however, the overall trait space occupied by species remains relatively similar, as revealed by the lack of significance in changes in functional richness. Indeed, no functional trait/group disappeared/appeared during the faunal replacement—a trend seen even during global mass extinction events . However, the increase in functional evenness, divergence, and disparity indicates that the functional trait space is more homogenously filled and more dispersed towards the Quaternary. Berke et al.  have shown that functional evenness in marine bivalves increases towards higher latitudes which is attributed to an evolutionary accumulation of taxa due to biogeographic dynamics. The paleoenvironmental shift from subtropical to temperate conditions and the loss of many molluscs of tropical affinity during the late Neogene  are consistent with this pattern.
A strong species sorting during the faunal turnover was responsible for the increase in FD over time. Both extinction and appearance of forms were selective according to ecological and life-history traits, as commonly seen in the fossil record [17, 19], though not driven by changes in the taxonomic composition of assemblages. Changes in FD can be attributed to the preferential loss of large-sized carnivores and the subsequent increase in the proportion of small-sized herbivore grazers and suspension-feeders. On the one hand, the loss of carnivory could be explained by two non-exclusive processes: i) the elevated losses during the Pliocene extinction, and ii) the reduced appearance of new forms during the Quaternary. Five carnivore families went extinct during the Pliocene, compared to only three families appearing in the Quaternary (Fig 5). In parallel, the appearance of new species within Muricidae, the most speciose family analyzed, was lower than expected by chance. On the other hand, the increasing importance in herbivory could be attributed to a null extinction of families, the diversification of surviving forms (e.g. limpets and turbid snails), and to the appearance of seven new families (Fig 5). Interestingly, the overall reduction in median body size did not occur within surviving families; i.e. this was remarkably stable across the Pliocene-Quaternary transition, and it is rather attributed to the appearance of small-sized herbivore families (Fig 5). Indeed, in agreement with previous studies [56, 80] a few surviving families (e.g. Volutidae, Muricidae, and Fissurellidae] show an increase in median body size. However, this is not consistent with the so-called “Lilliput Effect”, i.e. a miniaturization of species body size immediately after a large extinction event [81, 82], because the decline in body size is largely due to newly originated species.
Families were classified according to their feeding type and diversification dynamic. The solid line represents the null expectation of no change in median body size. The dotted line shows the fit of an OLS regression (r2 = 0.86, P < 0.001), where the slope (b = 1.15) was not different than the null expectation (P > 0.05). Also shown the median body size of families that went extinct or appeared. Families are depicted by numbers: 1 Buccinidae; 2 Bullidae; 3 Bursidae; 4 Calliostomatidae; 5 Calyptraeidae; 6 Cancellariidae; 7 Cassidae; 8 Cerithiidae; 9 Cliidae; 10 Columbellidae; 11 Drilliidae; 12 Ellobiidae; 13 Epitoniidae; 14 Fasciolariidae; 15 Fissurellidae; 16 Littorinidae; 17 Lottiidae; 18 Mangeliidae; 19 Marginellidae; 20 Mitridae; 21 Muricidae; 22 Nacellidae; 23 Nassariidae; 24 Naticidae; 25 Newtoniellidae; 26 Olividae; 27 Pseudolividae; 28 Pseudomelatomidae; 29 Ranellidae; 30 Rissoinidae; 31 Siphonariidae; 32 Tegulidae; 33 Trochidae; 34 Turbinidae; 35 Turridae; 36 Turritellidae; 37 Volutidae.
Previous studies have shown that the late Neogene extinction of bivalves and marine vertebrates along western South America were also trait-selective [22, 33]. This combined evidence suggests that the deep environmental transformations that took place during the Pliocene-Quaternary transition [71, 83] not only altered patterns of species diversity and composition but also might have brought a major shift in the functioning of marine ecosystems. Our results highlight the usefulness of FD indices to provide more detailed understanding of patterns of biotic turnover across evolutionary timescales.
S1 Table. Species occurrences in Pliocene and Quaternary sites.
We thank members of the Paleolab CEAZA, Alex Alballay, Jaime Villafaña, and Pablo Oyanadel, for their help collecting the information used. Geraat Vermeij and Nicole Webster provided very constructive comments that improved the manuscript. This work was funded by FONDECYT projects 1140841, 1150664 and INACH G_05–11.
- 1. Hooper DU, Chapin FS, Ewel JJ, Hector A, Inchausti P, Lavorel S, et al. Effects of biodiversity on ecosystem functioning: A consensus of current knowledge. Ecol Monogr. 2005;75(1):3–35.
- 2. Loreau M, Naeem S, Inchausti P, Bengtsson J, Grime JP, Hector A, et al. Ecology—Biodiversity and ecosystem functioning: Current knowledge and future challenges. Science. 2001;294(5543):804–8. pmid:11679658
- 3. Tilman D, Knops J, Wedin D, Reich P, Ritchie M, Siemann E. The influence of functional diversity and composition on ecosystem processes. Science. 1997;277(5330):1300–2.
- 4. Hillebrand H, Matthiessen B. Biodiversity in a complex world: consolidation and progress in functional biodiversity research. Ecol Lett. 2009;12(12):1405–19. pmid:19849711
- 5. Cardinale BJ, Srivastava DS, Duffy JE, Wright JP, Downing AL, Sankaran M, et al. Effects of biodiversity on the functioning of trophic groups and ecosystems. Nature. 2006;443(7114):989–92. pmid:17066035
- 6. Solan M, Cardinale BJ, Downing AL, Engelhardt KAM, Ruesink JL, Srivastava DS. Extinction and ecosystem function in the marine benthos. Science. 2004;306(5699):1177–80. pmid:15539601
- 7. Petchey OL, Gaston KJ. Functional diversity: back to basics and looking forward. Ecol Lett. 2006;9(6):741–58. pmid:16706917
- 8. Petchey OL, Gaston KJ. Extinction and the loss of functional diversity. Proc R Soc Lond, B, Biol Sci. 2002;269(1501):1721–7.
- 9. Petchey OL, Hector A, Gaston KJ. How do different measures of functional diversity perform? Ecology. 2004;85(3):847–57.
- 10. Poos MS, Walker SC, Jackson DA. Functional-diversity indices can be driven by methodological choices and species richness. Ecology. 2009;90(2):341–7. pmid:19323217
- 11. Schmera D, Eros T, Podani J. A measure for assessing functional diversity in ecological communities. Aquat Ecol. 2009;43(1):157–67.
- 12. Berke SK, Jablonski D, Krug AZ, Valentine JW. Origination and immigration drive latitudinal gradients in marine functional diversity. PLoS One. 2014;9(7):e101494. pmid:25036112
- 13. Stuart-Smith RD, Bates AE, Lefcheck JS, Duffy JE, Baker SC, Thomson RJ, et al. Integrating abundance and functional traits reveals new global hotspots of fish diversity. Nature. 2013;501(7468):539–42. pmid:24067714
- 14. Mouillot D, Villéger S, Parravicini V, Kulbicki M, Arias-González JE, Bender M, et al. Functional over-redundancy and high functional vulnerability in global fish faunas on tropical reefs. Proc Natl Acad Sci USA. 2014;111(38):13757–62. pmid:25225388
- 15. Boyer AG, Jetz W. Extinctions and the loss of ecological function in island bird communities. Global Ecol Biogeogr. 2014;23(6):679–88.
- 16. Foster WJ, Twitchett RJ. Functional diversity of marine ecosystems after the Late Permian mass extinction event. Nat Geosci. 2014;7(3):233–8.
- 17. Jablonski D. Species Selection: Theory and Data. Annu Rev Ecol Evol Syst. 2008;39:501–24.
- 18. Larsen TH, Williams NM, Kremen C. Extinction order and altered community structure rapidly disrupt ecosystem functioning. Ecology Letters. 2005;8(5):538–47. pmid:21352458
- 19. McKinney ML. Extinction vulnerability and selectivity: combining ecological and paleontological views. Annu Rev Ecol Syst. 1997;28:495–516.
- 20. Jablonski D. Mass extinctions and macroevolution. Paleobiology. 2005;31(2):192–210.
- 21. Smith AB, Jeffery CH. Selectivity of extinction among sea urchins at the end of the Cretaceous period. Nature. 1998;392(6671):69–71.
- 22. Rivadeneira MM, Marquet PA. Selective extinction of late Neogene bivalves on the temperate Pacific coast of South America. Paleobiology. 2007;33(3):455–68.
- 23. Smith JT, Roy K. Selectivity during background extinction: Plio-Pleistocene scallops in California. Paleobiology. 2006;32(3):408–16.
- 24. Johnson KG, Budd AF, Stemann TA. Extinction Selectivity and Ecology of Neogene Caribbean Reef Corals. Paleobiology. 1995;21(1):52–73.
- 25. Allmon WD. Paleontological completeness of the record of lower Tertiary mollusks, US Gulf and Atlantic coastal plains: implications for phylogenetic studies. Hist Biol. 1989;3:141–58.
- 26. Stanley SM, Campbell LD. Neogene mass extinction of Western Atlantic molluscs. Nature. 1981;293:457–9.
- 27. Jackson JBC, Jung P, Coates AG, Collins LS. Diversity and Extinction of Tropical American Mollusks and Emergence of the Isthmus of Panama. Science. 1993;260(5114):1624–6. pmid:17810203
- 28. Johnson KG, Curry GB. Regional biotic turnover dynamics in the Plio-Pleistocene molluscan fauna of the Wanganui Basin, New Zealand. Palaeogeogr, Palaeoclimatol, Palaeoecol. 2001;172(1–2):39–51.
- 29. Todd JA, Jackson JBC, Johnson KG, Fortunato HM, Heitz A, Alvarez M, et al. The ecology of extinction: molluscan feeding and faunal turnover in the Caribbean Neogene. Proc R Soc Lond, B, Biol Sci. 2002;269(1491):571–7.
- 30. Zachos J, Pagani M, Sloan L, Thomas E, Billups K. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science. 2001;292(5517):686–93. pmid:11326091
- 31. Philippi RA. Los fósiles Terciarios i Cuartarios de Chile. Leipzig: Imprenta Brockhaus; 1887. 256 p.
- 32. Kiel S, Nielsen SN. Quaternary origin of the inverse latitudinal diversity gradient among southern Chilean mollusks. Geology. 2010;38(10):955–8.
- 33. Villafaña JA, Rivadeneira MM. The rise and fall of the diversity of marine vertebrates during the Neogene on the temperate Pacific coast of South America. Paleobiology. 2014;40(4):659–74.
- 34. Herm D. Marines Pliozän und Pleistozän in Nord und Mittel-Chile unter besonderer Berücksichtigung der Entwicklung der Mollusken-Faunen. Zitteliana. 1969;2:1–159.
- 35. Le Roux JP, Olivares DM, Nielsen SN, Smith ND, Middleton H, Fenner J, et al. Bay sedimentation as controlled by regional crustal behaviour, local tectonics and eustatic sea-level changes: Coquimbo Formation (Miocene-Pliocene), Bay of Tongoy, central Chile. Sediment Geol. 2006;184(1–2):133–53.
- 36. Le Roux JP, Gomez C, Venegas C, Fenner J, Middleton H, Marchant M, et al. Neogene-Quaternary coastal and offshore sedimentation in north central Chile: Record of sea-level changes and implications for Andean tectonism. J South Amer Earth Sci. 2005;19(1):83–98.
- 37. Nielsen SN, Valdovinos C. Early Pleistocene mollusks of the Tubul Formation, South-Central Chile. Nautilus. 2008;122(4):201–16.
- 38. Rivadeneira MM, Carmona ER. A Late Pleistocene macrobenthic assemblage in Caleta Patillos, northern Chile: paleoecological and paleobiogeographical interpretations. Revista Geologica de Chile. 2008;35(1):163–73.
- 39. Guzmán N, Marquardt C, L. O, Frassinetti D, editors. La malacofauna Neogena y Cuaternaria del área de Caldera (27°-28° S): especies y rangos bioestratigráficos. Congreso Geológico Chileno, No 1; 2000.
- 40. Ortlieb L, Diaz A, Guzman N. A warm interglacial episode during Oxygen Isotope Stage 11 in northern Chile. Quaternary Science Reviews. 1996;15(8–9):857–71.
- 41. Ortlieb L, Goy JL, Zazo C, Hillaire-Marcel CI, Vargas G. Late Quaternary coastal changes in northern Chile. Guidebook for a fieldtrip, 23–25 November 1995. II Anual Meeting of the International Geological Correlation Program (IGCP), Project 367. Antofagasta: ORSTOM; 1995. 175 p.
- 42. Paskoff R, Leonard EM, Novoa JE, Ortlieb L, Radtke U, Wehmiller J. Field meeting in the La Serena-Coquimbo Bay area (Chile). Guidebook for a fieldtrip, 27–28 November 1995. II Anual Meeting of the International Geological Correlation Program (IGCP), Project 367. Antofagasta: ORSTOM; 1995. 69 p.
- 43. Ortlieb L, Guzmán N, Candia M. Moluscos litorales del Pleistoceno superior en el área de Antofagasta, Chile: primeras determinaciones e indicaciones paleoceanográficas. Estudios Oceanológicos. 1994;13:57–63.
- 44. Ortlieb L, DeVries T, Díaz A. Ocurrencia de Chione broggi (Pilsbry & Olsson, 1943) (Pelecypoda) en depósitos litorales Cuaternarios del sur del Perú: implicaciones paleoceanográficas. Boletín de la Sociedad Geológica del Perú. 1990;81:127–34.
- 45. Devries TJ. Concholepas Lamarck, 1801 (Neogastropoda, Muricoidea)—a Neogene Genus Native to South-America. Veliger. 1995;38(4):284–97.
- 46. DeVries TJ, Vermeij GJ. Herminespina: New genus of Neogene muricid gastropod from Peru and Chile. J Paleontol. 1997;71(4):610–5.
- 47. DeVries TJ. Acanthina Fischer von Waldheim, 1807 (Gastropoda: Muricidae), an ocenebrine genus endemic to South America. Veliger. 2003;46(4):332–50.
- 48. DeVries TJ, Hess B. Piscoacritia, gen. nov.: First account of tribe Trochini (Gastropoda: Trochidae: Trochinae) from the cenozoic of western South America. Veliger. 2004;47(1):6–12.
- 49. DeVries TJ. Pterorytis pacanana new species (Gastropoda: Muricidae): circumstantial evidence for late Pliocene El Nino events in southern Peru. Nautilus. 2005;119(4):164–8.
- 50. DeVries TJ. The late Cenozoic history of Xanthochorus Fischer, 1884 (Gastropoda: Muricidae) in western South America. Veliger. 2005;47(4):259–76.
- 51. DeVries TJ. Late Cenozoic Muricidae from Peru: Seven new species and a biogeographic summary. Veliger. 2005;47(4):277–93.
- 52. DeVries TJ. The Neogene history of Prisogaster Morch, 1850 (Gastropoda: Turbinidae) in South America. Nautilus. 2006;120(4):139–49.
- 53. DeVries TJ. Late Cenozoic Tegulinae (Gastropoda: Trochidae) from Southern Peru. Nautilus. 2007;121(4):163–81.
- 54. DeVries TJ. Cenozoic Turritellidae (Gastropoda) from southern Peru. J Paleontol. 2007;81(2):331–51.
- 55. DeVries TJ. Three new Pliocene species of Stramonita Schumacher, 1817 (Muricidae: Rapaninae) from western South America and the evolution of modern Stramonita chocolata (Duclos, 1832). Veliger. 2007;48(4):247–59.
- 56. DeVries TJ. Pliocene and Pleistocene Fissurella Bruguiere, 1789 (Gastropoda: Fissurellidae) from southern Peru. Veliger. 2008;50(2):129–48.
- 57. DeVries TJ. Cenozoic Nacella (Patellogastropoda: Nacellidae) from Peru and Chile: filling in the gaps. Veliger. 2008;50(4):274–91.
- 58. Cárdenas J, Gordillo S. Paleoenvironmental interpretation of late Quaternary molluscan assemblages from southern South America: A taphonomic comparison between the Strait of Magellan and the Beagle Channel. Andean geology. 2009;36(1):81–93.
- 59. Kowalewski M, Kiessling W, Aberhan M, Fürsich FT, Scarponi D, Wood SLB, et al. Ecological, taxonomic, and taphonomic components of the post-Paleozoic increase in sample-level species diversity of marine benthos. Paleobiology. 2006;32(4):533–61.
- 60. Hopkins MJ, Simpson C, Kiessling W. Differential niche dynamics among major marine invertebrate clades. Ecol Lett. 2014;17(3):314–23. pmid:24313951
- 61. Madin JS, Alroy J, Aberhan M, Fürsich FT, Kiessling W, Kosnik MA, et al. Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates. Science. 2006;312(5775):897–900. pmid:16690862
- 62. Valentine JW, Roy K, Jablonski D. Carnivore/non-carnivore ratios in northeastern Pacific marine gastropods. Marine Ecology-Progress Series. 2002;228:153–63.
- 63. Chao A, Lee SM. Estimating the Number of Classes Via Sample Coverage. J Am Stat Assoc. 1992;87(417):210–7.
- 64. Chao A. Non-parametric estimation of the number of classes in a population. Scand J Stat. 1984;11:265–70.
- 65. R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria URL http://wwwR-projectorg/2017.
- 66. Laliberte E, Legendre P. A distance-based framework for measuring functional diversity from multiple traits. Ecology. 2010;91(1):299–305. pmid:20380219
- 67. Villéger S, Mason NW, Mouillot D. New multidimensional functional diversity indices for a multifaceted framework in functional ecology. Ecology. 2008;89(8):2290–301. pmid:18724739
- 68. Möricke WV. Versteinerungen der Tertiärformationen von Chile. Neues Jahrbuch für Mineralogie, Geologie und Paläontologie Beilage Band. 1896;10:548–612.
- 69. Dowsett HJ, Robinson MM, Foley KM. Pliocene three-dimensional global ocean temperature reconstruction. Clim Past. 2009;5:769–83.
- 70. Dowsett HJ, Robinson MM. Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: a multi-proxy perspective. Phil Trans R Soc A. 2009;367(1886):109–25. pmid:18854303
- 71. Dekens PS, Ravelo AC, McCarthy MD. Warm upwelling regions in the Pliocene warm period. Paleoceanography. 2007;22(3).
- 72. Valenzuela-Toro AM, Gutstein CS, Varas-Malca RM, Suarez ME, Pyenson ND. Pinniped turnover in the South Pacific Ocean: new evidence from the Plio-Pleistocene of the Atacama Desert, Chile. J Vert Paleontol. 2013;33(1):216–23.
- 73. González-Wevar CA, Nakano T, Cañete JI, Poulin E. Molecular phylogeny and historical biogeography of Nacella (Patellogastropoda: Nacellidae) in the Southern Ocean. Mol Phylogen Evol. 2010;56(1):115–24.
- 74. Aberhan M, Kiessling W. Persistent ecological shifts in marine molluscan assemblages across the end-Cretaceous mass extinction. Proc Natl Acad Sci USA. 2015;112(23):7207–12. pmid:25941366
- 75. Bush AM, Bambach RK. Paleoecologic megatrends in marine metazoa. Annu Rev Earth Planet Sci. 2011;39:241–69.
- 76. Villeger S, Novack‐Gottshall PM, Mouillot D. The multidimensionality of the niche reveals functional diversity changes in benthic marine biotas across geological time. Ecol Lett. 2011;14(6):561–8. pmid:21481126
- 77. Dineen AA, Fraiser ML, Sheehan PM. Quantifying functional diversity in pre- and post-extinction paleocommunities: A test of ecological restructuring after the end-Permian mass extinction. Earth-Sci Rev. 2014;136:339–49.
- 78. Dineen AA, Fraiser ML, Tong J. Low functional evenness in a post-extinction Anisian (Middle Triassic) paleocommunity: a case study of the Leidapo Member (Qingyan Formation), south China. Global Planet Change. 2015;133:79–86.
- 79. Nielsen SN, Glodny J. Early Miocene subtropical water temperatures in the southeast Pacific. Palaeogeogr, Palaeoclimatol, Palaeoecol. 2009;280(3):480–8.
- 80. Vermeij GJ. The evolution of gigantism on temperate seashores. Biol J Linn Soc. 2012;106(4):776–93.
- 81. Twitchett RJ. The Lilliput effect in the aftermath of the end-Permian extinction event. Palaeogeogr, Palaeoclimatol, Palaeoecol. 2007;252(1):132–44.
- 82. Keller G, Abramovich S. Lilliput effect in late Maastrichtian planktic foraminifera: Response to environmental stress. Palaeogeogr, Palaeoclimatol, Palaeoecol. 2009;284(1):47–62.
- 83. Garreaud RD, Molina A, Farias M. Andean uplift, ocean cooling and Atacama hyperaridity: A climate modeling perspective. Earth Planet Sc Lett. 2010;292(1):39–50.