Taphonomic Alteration Research Articles

Intraspecific variation and taphonomic alteration in the Cambrian (Furongian) agnostoid Lotagnostus americanus: new information from China

The concept of the agnostoid arthropod species Lotagnostus americanus (Billings, 1860), which has been reported from numerous localities in the upper Furongian Series (Cambrian) of Laurentia, Gondwana, Baltica, Avalonia, and Siberia, is reviewed with emphasis on morphologic and taphonomic information afforded by large collections from Hunan in South China, Xinjiang in Northwest China, and Zhejiang in Southeast China. Comparisons are made with type and topotype material from Quebec, Canada, as well as material from elsewhere in Canada, the USA, the United Kingdom, Sweden, Russia, and Kazakhstan. The new information clarifies the limits of morphologic variability in L. americanus owing to ontogenetic changes and variation within holaspides, including inferred microevolution. It also provides details on apparent variation of taphonomic origin. The Chinese collections demonstrate a moderately wide variation in L. americanus, indicating that arguments favoring restriction of Lotagnostus species to narrowly defined, geographically restricted forms are unwarranted. Species described as L. trisectus (Salter, 1864), L. asiaticus Troedsson, 1937, and L. punctatus Lu, 1964, for example, fall within the range of variation observed in L. americanus, and are regarded as junior synonyms. The effaced form Lotagnosilis obscurus Palmer, 1955 is removed from synonymy with L. americanus. A review of the stratigraphic distribution of L. americanus as construed here shows that the earliest occurrences of the species in all regions of the world are nearly synchronous. (Less)

The revival of a so-called rotten fish: the ontogeny of the Devonian acanthodian Triazeugacanthus.

Since its original description as a chordate, the Late Devonian Scaumenella mesacanthi has been interpreted alternately as a prochordate, a larval ostracoderm and an immature acanthodian. For the past 30 years, these minute specimens were generally considered as decayed acanthodians, most of them belonging to Triazeugacanthus affinis. Among the abundant material of 'Scaumenella', we identified a size series of 188 specimens of Triazeugacanthus based on otolith characteristics. Despite taphonomic alteration, we describe proportional growth and progressive appearance of skeletal elements through size increase. Three ontogenetic stages are identified based on squamation extent, ossification completion and allometric growth. We demonstrate that what has been interpreted previously as various degrees of decomposition corresponds to ontogenetic changes.

Taphonomy of a clypeasteroid echinoid using a new quasimetric approach

A new quasimetric approach is used to statistically analyze taphonomic data from a commonly occurring shallow water clypeasteroid echinoid in order to obtain metric equivalent measurements of taphonomic alteration on an interval-like scale. This technique takes the character condition as well as its proportion into account and translates the taphonomic alteration into data, which behave as interval scaled and thus allows for the use of parametric as well as non-parametric statistics. Tests of Echinocyamus pusillus from Giglio Island (Mediterranean Sea, Italy) were analyzed with respect to a suite of taphonomic features including abrasion of the test surface, tubercles, ambulacral and genital pore margins as well as, if present, the outline and cross section of predatory drillholes. The degree of fragmentation and encrustation was also determined. Taphonomic features were analyzed using a semi-quantitative approach with three degrees of test alteration including non-altered, moderately altered, and highly ...

TAPHONOMIC DIFFERENCES IN MOLLUSCAN SHELL PRESERVATION IN FRESHWATER ENVIRONMENTS FROM THE SOUTHEASTERN PAMPAS, ARGENTINA

Actualistic studies in freshwater environments are scarce, limiting the interpretation of paleoenvironmental information obtained from the fossil record. The objectives of this study are to assess the taphonomic factors that affect the formation of mollusk assemblages in freshwater environments of the pampean region. Twenty sites were analyzed at regional (La Brava and Nahuel Ruca) and environmental (lentic and lotic) scales. Shells were primarily affected by loss of proteinaceous parts, fragmentation, and fine-scale surface alteration. Taphonomic differences were observed in dead shell condition related to environmental conditions and faunistic composition (thin-/thick-shelled species proportion) in spite of the dominance of one species, Heleobia parchappii. The differences were related to extrinsic (environmental) factors probably due to differential influence of organic decay, microbioerosion, and/or dissolution. However, intrinsic factors, especially those related to differential preservation and input rates of thin-/thick-shelled species, may be also biasing the compositional fidelity of death assemblages. Although the degree of taphonomic alteration across locales and environments was evident, all mollusk assemblages still preserved their biological signature from the precursor communities.

An integrated approach to the taxonomic identification of prehistoric shell ornaments.

Shell beads appear to have been one of the earliest examples of personal adornments. Marine shells identified far from the shore evidence long-distance transport and imply networks of exchange and negotiation. However, worked beads lose taxonomic clues to identification, and this may be compounded by taphonomic alteration. Consequently, the significance of this key early artefact may be underestimated. We report the use of bulk amino acid composition of the stable intra-crystalline proteins preserved in shell biominerals and the application of pattern recognition methods to a large dataset (777 samples) to demonstrate that taxonomic identification can be achieved at genus level. Amino acid analyses are fast (<2 hours per sample) and micro-destructive (sample size <2 mg). Their integration with non-destructive techniques provides a valuable and affordable tool, which can be used by archaeologists and museum curators to gain insight into early exploitation of natural resources by humans. Here we combine amino acid analyses, macro- and microstructural observations (by light microscopy and scanning electron microscopy) and Raman spectroscopy to try to identify the raw material used for beads discovered at the Early Bronze Age site of Great Cornard (UK). Our results show that at least two shell taxa were used and we hypothesise that these were sourced locally.

New data on the palaeobiology of the enigmatic yunnanozoans from theChengjiangBiota,LowerCambrian,China

AbstractInterpretation of the enigmatic soft‐bodied yunnanozoans from theLowerCambrian (Stage 3,Series 2)ChengjiangBiota has remained controversial for decades because of their strange body plan and their variable taphonomic alteration. Proposed affinities have ranged from stem bilaterian to stem vertebrate. A study of over seven hundred slabs, many newly collected, from five sections at two localities demonstrates that yunnanozoans have sclerotized dorsal and axial segments, a body cavity, a unique feeding region and a coiled alimentary canal. Although two genera have been previously discriminated, all specimens have the same number of filamentous arches (seven pairs) and of ventral circular structures (four pairs); this indicates thatHaikouellaChen,Huang andLi, 1999 is a junior synonym ofYunnanozoonHou,Ramsköld andBergström, 1991. Our analysis reveals new details of the putative pharyngeal pores ofYunnanozoon lividum,and although there are similarities with the gill slits of deuterostomes, the question of their homology remains moot. The filamentous arches and their supporting rods were probably sclerotized and represent a specialized feeding structure. Yunnanozoans exhibit characters that are open to a number of alternative interpretations of putative homology, encompassing comparisons with deuterostomes and protostomes (including members of thePlatyzoa). Given their unique features, and the current lack of secure homologies, the affinities of yunnanozoans should continue to be considered in a wider bilaterian context.

Sediment transport trends from a tropical Pacific lagoon as indicated by Homotrema rubra taphonomy: Wallis Island, Polynesia

The assessment of sediment transport pathways in carbonate settings is complicated by ecologically sourced sediment. Tracers such as foraminifera have previously been used in these settings to describe the movement of coastal sediments on spatial and temporal scales where traditional grain size methods have limited use. The present study builds on the foraminifera-based tracer method by using Homotrema rubra, a foraminifer with an attached life habit (i.e., defined provenance in the reef) to document modern sediment transport trends at Wallis Island, a tropical Pacific lagoon. At Wallis Island, Homotrema taphonomic results discriminated amongst modern reef, lagoon, and island (beach) samples. Reef samples contained high concentrations of fragments that were large (> 250 μm) and exceptionally- to well-preserved (e.g., intact chambers, red color, angularity). In general, concentrations and degree of taphonomic alteration decreased with distance landward from the reef; lagoon samples were characterized by lower concentrations of Homotrema that were smaller in size and less preserved (e.g., pink in color, no chamber structure, rounding of edges). At the greatest distance from the reef, island (beach) samples contained the lowest concentrations of Homotrema fragments that were small, well rounded and bleached. In this regard, Homotrema taphonomy is a useful indicator of the direction and forcing of sediment transport and will therefore be useful in detecting overwash deposits in tropical settings, where distinguishing event deposits from surrounding sediment is problematic.

Toros-Menalla (Chad, 7 Ma), the earliest hominin-bearing area: How many mammal paleocommunities?

The fossiliferous area of Toros-Menalla (TM) (Djurab Desert, northern Chad) has yielded one of the richest African mammal faunas of the late Miocene. It is also the place where the earliest known hominin, Sahelanthropus tchadensis, was found. Although more than 300 localities are recorded in that area, previous paleoecological studies focused only on the largest and richest one. The integration of the material from other TM localities, and thus of a significant number of mammal taxa, is crucial to improve the corresponding paleoenvironmental reconstructions. Before such inferences can be drawn, it is necessary to test for the ecological integrity of these mammal assemblages: how many paleocommunities do they represent?The faunal structures of several assemblages selected for their apparent resilience to sampling biases are compared here. The criteria used in the inter-assemblage comparison are ecological diversity, taxonomic structure (taxonomic rank of abundance) and taxonomic composition. Based on multivariate analyses, two groups of TM assemblages can be distinguished. One of them contains the hominin-bearing assemblages. It is taxonomically richer and shows a wider ecological spectrum than its counterpart. The degree of taphonomic alteration undergone by the TM assemblages, as well as the distribution of amphibious mammals among them, suggest different depositional settings for these two groups of assemblages, the richest of which was probably associated with lower hydraulic energy. Overall, it seems that the TM assemblages recorded the same mammal paleocommunity preserved in two contrasted depositional settings. Moreover, the spatial overlap of these assemblages provides further evidence for the mosaic character of the landscape associated with S. tchadensis.

What causes failure (overheating) during lithic heat treatment?

Heat treatment of lithic raw material, i.e. the intentional alteration of silica rocks for improving their knapping quality, is a process that may require great care and precisely controlled conditions in order to avoid failure due to overheating. The physical causes of overheating remain poorly understood leading to problems in the interpretation of heat-treated artefacts and/or fire-related taphonomic alteration of different types of silica rocks. This driving force of overheating is investigated by a set of experimental heat treatment sequences with different ramp rates and different volumes of flint with a well-defined mineralogical composition, porosity and water content. The results of this experiment show the main cause of heat-induced fracturing to be the vapour pressure in fluid inclusions within the rocks. Heterogeneous thermal expansion could be discarded. The interdependence between volume and heating rate is also shown. These results have implications for the study of archaeological heat-treated rocks, the understanding of taphonomic heat-induced fracturing of silica rocks and experimental flint knapping.

New bethylid and chrysidid wasps (Hymenoptera: Chrysidoidea) from Canadian Late Cretaceous amber

A new bethylid species, Celonophamia gran- ama, and two new chrysidid species, Procleptes eoliami, and P. hopejohnsonae, are described from Late Cretaceous (Campanian) amber collected at the Grassy Lake locality in Alberta, Canada. Within the deposit these taxa constitute the first bethylid, and the second and third chrysidid species to be described, respectively. The new taxa expand the sparse fossil record of Chrysidoidea, particularly that of Chrysididae—a group that was previously represented by only three described species in the Mesozoic. The presence of Celonophamia species in both Canadian amber and Siberian (Taimyr) amber further emphasizes faunal simi- larities between these two northern Late Cretaceous amber deposits. Given the prevalence of metallic coloration in Chrysididae, the specimens described here also provide evidence for the taphonomic alteration of perceived insect colors in Cretaceous amber inclusions.

The Post‐Mortem Pressure Distortion of Human Crania Uncovered in an Early Medieval Pohansko (Czech Republic) Graveyard

AbstractPost‐mortem distortion resulting from the pressure of overlying sediments (i.e. grave backfill) is one of the taphonomic factors capable of altering the geometry of buried and subsequently recovered skeletal remains. If pressure distortion is a frequent occurrence, it could systematically flaw the outcome of an anthropological examination. To study the patterns of post‐mortem distortion in buried crania and shape alterations associated with a specimen's in situ position, 46 male crania recovered from an Old Slavic graveyard (Pohansko, Czech Republic) were analysed together with control specimens from four modern European osteological collections (N = 207) using geometric morphometrics. The results indicate a common pattern of shape change in buried skulls associated with their in situ orientation. However, as the overall shape variation between the Old Slavic crania (which, with their tendency towards longer, narrower shapes differed markedly from the modern Czech crania) oriented in situ on their back and side reflects the duality of dolichocranial and brachycranial forms, it seems likely that the in situ positioning of the crania stemmed from their original morphology. The lack of substantial effect of the in situ orientation on the cranial morphology is associated with a larger cranial size and a tendency for sturdiness in the Old Slavic subsample. Both of these characteristics are likely to be contributing to the resistance of these crania to taphonomic alterations. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Origin and Significance of Late Cretaceous Bioevents: Examples from the Cenomanian

Palaeontological events, documented by widespread beds or thin intervals of strata with either unusual (“exotic”) or acmes of common faunal elements are a characteristic feature of Upper Cretaceous epicontinental shelf sediments in NW Europe. Their importance in stratigraphic calibration has early been recognized and these “bioevents” are widely used as correlation tools. Furthermore, it appears that there is a genetic link between sequence and event stratigraphy as most of the “classic” bioevents developed during specific intervals of a 3rd-order depositional sequence. Early transgressive bioevents (ETBs) are subdivided into two subtypes, i.e., the lag and migration subtype. The lag subtype corresponds to the transgressive surface and develops in response to winnowing and relative enrichment of robust biogenic hardparts. Taphonomic alteration and time-averaging are important features. The migration subtype is related to the disappearance of physical or ecological barriers that triggered faunal migrations...

Análisis Tafonómico de Moluscos Por Debajo de la Interfase Agua-Sedimento en la Laguna Nahuel Rucá (Provincia de Buenos Aires, Argentina)

Abstract. TAPHONOMIC ANALYSIS OF MOLLUSKS BELOW THE SEDIMENT-WATER INTERFACE IN NAHUEL RUCA LAKE (BUENOS AIRES PROVINCE, ARGENTINA). The preservation of mollusk remains below the sediment-water interface in Nahuel Ruca lake (37°37′S–57°25′W) was analyzed in order to determine the degree of taphonomic alteration and to estimate the vertical extension of the taphonomically active zone (TAZ). To achieve that, the preservation patterns observed in five cores sampled from the littoral zone were described, and the effect of depth and presence of periostracum on shell dissolution was assessed by means of a field experiment. In all cores the recovered remains were dominated by fragments. Seven species were found: Biomphalaria peregrina (d'orbigny, 1835), Drepanotrema kermatoides (d'Orbigny, 1835), Heleobia australis (d'Orbigny, 1835), H. parchappii (d'Orbigny, 1835), Pomacea canaliculata (Lamarck, 1801), Uncancylus concentricus (d'Orbigny, 1835) and Musculium argentinum (d'Orbigny, 1835). We concluded that the TA...

Late-glacial to Holocene transition in northern Spain deduced from land-snail shelly accumulations

Shells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial–Holocene (~12.1–6.3calka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ13C values were −10.3±1.1‰, −8.2±2.3‰, and −7.3±1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ13C values during the late-glacial and some Holocene periods imply higher water stress of C3 plants and/or higher limestone contribution than today. Intrashell δ13C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ18O values were −1.1±0.7‰, −0.9±0.8‰ and −0.1±0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~12.1−10.9calka BP conditions were drier and became wetter at ~8.4−6.3calka BP and today. Intrashell δ18O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ18O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.

SEASONAL VARIATION IN ECOLOGICAL AND TAPHONOMIC PROCESSES RECORDED IN SHELLY DEATH ASSEMBLAGES

Modern valves of Lucina pensylvanica (Bivalvia: Lucinidae) were analyzed for 18O/16O ratios, drilling predation traces, biometric measurements, and taphonomic descriptors to explore seasonal variations in ecological and taphonomic processes within a death assemblage from Grand Bahama Island. The d18O values at the shell margin (5last growth episode) were used as a proxy for temperature at the time closest to the organism’s death. Temperature estimates suggest that most individuals died in warmer months, whereas mortality appeared to have been lower during cooler seasons ( ,24 6C). Only drilled valves yielded the coldest temperatures at the shell margin (,18.1–21.3 6C), whereas exclusively undrilled valves exhibited the hottest temperatures at the last growth episode (,25.5–26.5 6C). Drilled valves were significantly smaller and exhibited higher taphonomic alteration than undrilled valves, pointing to postmortem transport and sorting. While seasonal variations in predation and growth rates may have affected the observed patterns to some extent, the results, at least partly, reflect hydrodynamic variations throughout the year, which may have induced seasonal variation in postmortem sorting of drilled and undrilled valves. This study illustrates that, by combining geochemical proxies and quantitative paleoecological data, more informed ecologic and taphonomic interpretations can be achieved for subfossil and fossil assemblages.

Redescripción y Significado Paleoambiental deHeleobia ameghini(Doering, 1884) (Gastropoda: Rissooidea) en el Pleistoceno Tardío de la Provincia de Buenos Aires, Argentina

REDESCRIPTION AND PALEOENVIRONMENTAL SIGNIFICANCE OF HELEOBIA AMEGHINI (DOERING, 1884) (GASTROPODA: RISSOOIDEA) FROM THE LATE PLEISTOCENE OF BUENOS AIRES PROVINCE, ARGENTINA. New remains of Heleobia ameghini (Doering, 1884) are analysed. This is an extinct late Pleistocene gastropod species recovered from alluvial sections along the middle course of the Luján River. Detailed observations allowed establishing the main diagnostic characteristics of the species; these are compared with the data provided in the original description of this taxon. Its paleoenvironmental significance is also discussed in context with the stratigraphic setting and the accompanying fauna. Heleobia ameghini is characterized by its small size, which varies between 0.75 and 6.75 mm in length. Shells are globose, with the last whorl highly developed, in a similar way to the modern Heleobia piscium (d'Orbigny, 1835), from which it differs by their relative higher size and the lower convexity of the whorls. The poor preservation of the specimens and the bell-shaped size-frequency distribution suggest an important taphonomic alteration, which may be consequence of the dissolution processes that occurred during the biostratinomic or diagenetic stage. It is concluded that Heleobia ameghini tolerated significant salinity fluctuations, inhabiting fluvial environments subjected to recurrent episodes of storm-flooding alternated with moments of waterflow decrease. The latter were responsible for the development of ponds and eventually dry ponds during drought periods and thus higher salinity values.

Changes in human bones boiled in seawater

The differences between boiled or unboiled bones are not often studied. However, they are crucial to understand postmortem rituals and to establish defleshing procedures and mortuary practices. In this work, human bones boiled in sea or fresh water are characterized. The bone composition, as well as the compounds present in the resulting materials, shows that salt alters the boiling process mechanism. Hence, from structural and morphological criteria, it is possible to distinguish if a bone has been boiled in salt or fresh water. In both sets of samples, the smoothness of the bone surface depends on boiling time, but only in bones boiled in seawater, filaments are observed apparently pouring out of the pores.Those differences which are mainly morphological (smoothness of the surface) are explained in terms of a collagen diffusional mechanism favored by sodium and chloride ions. For a boiling time of 6 h, the surface is covered by a thick layer or crusts of degraded collagen. Experiments with seawater may be used as model experiments to simulate taphonomical alterations in bones exposed to salt water.

EVALUATING TAPHONOMIC BIAS OF PALEOECOLOGICAL DATA IN FOSSIL BENTHIC FORAMINIFERAL ASSEMBLAGES

Paleoecological analyses conducted over broad temporal and spatial scales can incorporate fossil assemblages of disparate taphonomic histories, resulting in samples where the record of the original communities is biased to different degrees. Testing for the effects of differential taphonomic biases is crucial to accurate interpretations of paleoecological patterns. To test for such effects in a shallow-marine benthic foraminiferal record from the early Miocene Astoria Formation, I developed a taphonomic grading system for benthic foraminifera and scored individuals for preservation state. Grading allows each sample to be subdivided into taphonomically similar subsamples. Subsamples are evaluated for similarity in species composition, species rank, and proportional abundances. Similarities are significantly higher in within-sample comparisons between taphonomic grades than they are among samples when taphonomic grade is held constant, indicating that ecological information is conserved despite variation in taphonomic grade within a single time-averaged assemblage. In addition, taphonomically homogenous subsamples (and nested sets of taphonomic grades) capture the same temporal patterns of species richness, community evenness, and the proportional abundances, although ordinations using subsamples with the poorest preservation do show some significant differences. Thus, although incorporating the most poorly preserved samples requires some caution, the quality of ecological information derived from these benthic foraminiferal samples is consistent across taphonomic grades. For this test case, I argue that paleoecological analyses will not be significantly affected by differences in preservation among samples. This method of taphonomic grading can be applied to other fossil groups and facilitates analyses of paleoecological results despite different degrees of taphonomic alteration.

A Bioarchaeological Investigation into the Human Remains Discovered in the Chloorkop Area, South Africa

ABSTRACTIn November 2008, human skeletal remains were discovered during construction works undertaken by Carlop Properties in the Chloorkop industrial area, Kempton Park, Gauteng. The Forensic Anthropology Unit of the University of Pretoria, Forensic Anthropology Research Centre (FARC) was notified, and rescue excavations of both the exposed and the undisturbed remains were undertaken. The skeletonised remains of at least 18 individuals were recovered and sent to the Department of Anatomy at the University of Pretoria for standard anthropological analysis. The identity and the time period of these human remains are unknown, and during social consultation, no relatives could be identified. Excavations revealed a formal burial pattern, which suggests a formal cemetery, probably associated with a historic institution. All individuals were buried in wooden coffins in an extended, supine position. The remains consist of both adult and juvenile remains. Some of the remains were found in a commingled state because of disturbance caused by construction work. The minimum number of individuals was determined by the visual pair matching of skeletal elements on the basis of similarities observed in bone morphology, age and sex, trauma and pathology and taphonomic alterations. Bioarchaeological techniques were used, and the following results were obtained. Of the 18 individuals, at least 15 were identified to be males, one possibly female and two juveniles. At least five of the adult male individuals presented with cut marks associated with standard autopsy procedures. No reference to the individuals' identity or to the context of the cemetery within the historical span of the Chloorkop area has been located. However, the burial pattern observed, as well as the demographic profile and pathology observed on the skeletal remains, suggests that these individuals could be linked to the Klipfontein Organic Products Factory (ca 1941s–1970s), which employed many migrant labourers, most to whom lived in compounds on the factory premises. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Dissolution susceptibility of Paleocene–Eocene planktic foraminifera: Implications for palaeoceanographic reconstructions

We investigated shell characteristics and differential dissolution susceptibility of planktic foraminiferal species derived from upper Paleocene and lower Eocene deep-sea sequences, Ocean Drilling Program (ODP) Site 865 (Allison Guyot) and Sites 1209B, 1210B and 1212A (Shatsky Rise) in the North Pacific Ocean. The purposes of this study are: 1) assessing the effects of differential dissolution on upper Paleocene–lower Eocene planktic foraminiferal assemblages, at species level and within different biozones, to quantify dissolution susceptibility of genera and species; 2) investigating the differences in shell characteristics; 3) revealing the relationship between shell parameters and dissolution robustness of taxa, and 4) identifying the key shell parameter(s) influencing the dissolution susceptibility of foraminiferal taxa. Two independent experiments were carried out, one focusing on gradual qualitative deterioration of taxa by dissolution and the other documenting the weight loss of taxa. Shell parameters such as wall thickness, porosity and pore size were determined through Scanning Electron Microscopy (SEM) and image analysis (JMicroVision). We found that the large muricate Acarinina and Morozovella are most resistant, followed by the cancellate Subbotina and the small muricate Igorina , confirming results of previous work. At species level, the thick-walled Acarinina soldadoensis , Acarinina subsphaerica and the large Morozovella subbotinae are the most resistant species. Most of the large Morozovella species such as Morozovella aequa , Morozovella formosa-gracilis , Morozovella velascoensis and Morozovella pasionensis , together with Acarinina nitida show intermediate dissolution resistance, whereas the small muricate Igorina species, the cancellate Subbotina velascoensis and the thin-walled Morozovella acuta and Morozovella occlusa are the most vulnerable species. We propose a formula for calculating the dissolution resistance of taxa based on their wall thickness and size — two key parameters in dissolution resistance of a species. Application of this formula reveals good agreement between the calculated and measured dissolution resistance, indicating its robustness. Furthermore, the agreement between our experimental results, in-situ experimental results on live foraminifera and natural quantitative/qualitative records suggests that our experiments accurately mimic natural dissolution processes. Consequently, these experimental results strongly bear on interpretations of foraminiferal dissolution in natural environments, especially in studies on early Paleogene climatic events that are often associated with dissolution phenomena. More generally, a proper assessment of taphonomic alteration by dissolution should be part of every paleoenvironmental reconstruction based on quantitative foraminiferal records. ► We investigate the effects of differential dissolution on upper Paleogene planktic foraminifera: ► The differences in shell characteristics of planktic species. ► The relationship between shell parameters and dissolution robustness. ► The key parameters in dissolution susceptibility of these planktic taxa. ► From this, we propose a dissolution resistance formula for planktic foraminiferal taxa.