Artifact Of Preservation Research Articles

A taxonomic reassessment of Cirrodrilus japonicus (Pierantoni, 1912) (Annelida, Clitellata, Branchiobdellida)

Cirrodrilus japonicus (Pierantoni, 1912) has not been identified since it was originally described from specimens removed from preserved Japanese crayfish that had been deposited in the Natural History Museum in Hamburg, Germany. A morphological comparison of the published description and recently discovered syntypes of C. japonicus from the Hamburg Museum with syntypes and newly collected material of Cirrodrilus ezoensis (Yamaguchi, 1934), supported the view that preservation artifacts in C. japonicus caused Prof. Yamaguchi to believe his well-preserved specimens were member of a separate species. Therefore, C. ezoensis becomes a junior synonym of C. japonicus.

Back to life: Techniques for developing high-quality 3D reconstructions of plants and animals from digitized specimens.

Expanded use of 3D imaging in organismal biology and paleontology has substantially enhanced the ability to visualize and analyze specimens. These techniques have improved our understanding of the anatomy of many taxa, and the integration of downstream computational tools applied to 3D datasets have broadened the range of analyses that can be performed (e.g., finite element analyses, geometric morphometrics, biomechanical modeling, physical modeling using 3D printing). However, morphological analyses inevitably present challenges, particularly in fossil taxa where taphonomic or preservational artifacts distort and reduce the fidelity of the original morphology through shearing, compression, and disarticulation, for example. Here, we present a compilation of techniques to build high-quality 3D digital models of extant and fossil taxa from 3D imaging data using freely available software for students and educators. Our case studies and associated step-by-step supplementary tutorials present instructions for working with reconstructions of plants and animals to directly address and resolve common issues with 3D imaging data. The strategies demonstrated here optimize scientific accuracy and computational efficiency and can be applied to a broad range of taxa.

New specimens and supplementary descriptions of two rare dragonfishes, Photonectes klepadloae and P. litvinovi, with comments on the distribution of P. filipendulus (Teleostei: Stomiidae: Melanostomiinae)

Supplementary descriptions based on new specimens of two rare dragonfish species, Photonectes klepadloae and P. litvinovi, formerly known by the holotypes only, are presented. The presence of a bulbous swelling at the tip of the terminal filament of the mental barbel is documented for P. klepadloae, and its absence in some specimens of that species, including the holotype, is likely an artifact of preservation. The presence of blue luminous tissue is documented for P. litvinovi, which was formerly believed to lack it due to skin abrasion in the holotype. A key for the species is corrected based on the new diagnostic characters of P. litvinovi. Incorrect mapping of the distribution of P. filipendulus provided in the original description is improved and a map showing the known distribution of all three aforementioned species is presented.

Rediscovery, redescription and identity of Pristimantis nebulosus (Henle, 1992), and description of a new terrestrial-breeding frog from montane rainforests of central Peru (Anura, Strabomantidae)

The taxonomic status of the strabomantid frog species Pristimantis nebulosus (Henle, 1992), originating from the southern Cordillera Azul in central Peru, is investigated based on examination of the holotype and its comparison with freshly collected topotypic material. Following current standards, we provide a redescription of the holotype. It is in a rather poor state and exhibits certain damages and preservation artifacts, conditions that have hampered an allocation of this nominal taxon to any known living population of Pristimantis in the past. Our detailed specimen-to-specimen comparison provided morphological evidence for the conspecifity of the holotype and freshly collected topotypes. Molecular phylogenetic analysis, based on the mitochondrial 16S gene fragment places P. nebulosus in the P. conspicillatus species group, being closely related to P. bipunctatus and an undescribed candidate species from the Cordillera de Carpish. From both, P. nebulosus differs by considerable divergence in the 16S gene (p-distance 4.1–6.2%). Based on the specimens available, we provide an updated diagnosis for P. nebulosus, compare it to other species in the P. conspicillatus group and describe its advertisement call. In addition, we describe and name the closely related candidate species from the Cordillera de Carpish. It is sister to P. bipunctatus and P. nebulosus, but differs from both mainly by its tuberculate dorsal skin (versus shagreen) and divergence in the 16S gene (3.3–4.1%). We briefly discuss cryptic species diversity in the P. conspicillatus and P. danae species groups and provide justification for the description of a singleton species.

Coupled Coccolith-Based Temperature and Productivity High-Resolution Reconstructions in the Eastern Equatorial Pacific During the Last Deglaciation and the Holocene

We present a new high-resolution reconstruction of annual sea-surface temperatures (SSTa) and net primary productivity (NPP) using novel coccolithophore-based models developed for the Eastern Equatorial Pacific (EEP). We combined published coccolithophore census counts from core-tops in the Eastern Pacific with 32 new samples from the Equatorial region, to derive a new statistical model to reconstruct SSTa. Results show that the addition of the new EEP samples improves existing coccolithophore-based SST-calibrations, and allow reconstructing SSTa in the EEP with higher confidence. We also merged the relative abundance of deep-photic species Florisphaera profunda in the same surface sediment samples with existing calibration datasets for tropical regions, to reconstruct annual NPP. Both temperature and productivity calibrations were successfully applied to fossil coccolith data from Ocean Drilling Project Site 1240, in the EEP. The coccolith-based SSTa estimates show a cooling during the Last Glacial Maximum (LGM) and the Younger Dryas, and warming at the start of the Holocene. This pattern differs in the timing and magnitude of the temperature changes from other available SST-reconstructions based on biogeochemical and faunal proxies. We discuss these discrepancies to be the result of different proxy sensitivities to insolation forcing, seasonal bias, and/or preservation artifacts. Reconstructed annual NPP shows a general decreasing trend from the late last glacial period to recent times, which we relate to the weakening of wind-driven equatorial upwelling towards the Holocene. We also calculated carbon export using our SSTa and NPP reconstructions, and compared to other geochemical-based reconstructions for the same location. Our coupled SSTa-NPP reconstruction provides key data to more fully assess the evolution of primary and export productivity as well as organic carbon burial in the EEP, with implications for its role in global biogeochemical cycles across glacial terminations.

First Report of Hemipenial Variation among Some Genera and Species of Shieldtail Snakes (Serpentes: Uropeltidae) from India and Sri Lanka

Hemipenial characteristics have historically provided a wealth of comparative morphological characters for the systematic classification of snakes. However, the organs remain poorly known in many groups, particularly tropical and burrowing lineages. Here, we report on hemipenial morphology for 12 species from five genera from the family Uropeltidae: Melanophidium punctatum, M. cf. wynaudense, Plectrurus perrotetii, Rhinophis karinthandani, R. melanoleucus, R. saffragamus, R. sanguineus, Teretrurus cf. hewstoni, Uropeltis bhupathyi, U. cf. ceylanica, U. macrolepis, and U. rajendrani. Many are photographed or illustrated here for the first time. In Melanophidium, the organ is bulbous and mushroom-shaped, with the sulcus spermaticus winding through numerous convoluted folds. In Plectrurus and Teretrurus, it is simple, smooth, and conical. In Sri Lankan Rhinophis and some Uropeltis, the organ generally resembles previously described hemipenes from other species in those genera in being simple, subcylindrical, and covered in fine spines. However, a median lobular process is observed in the Indian species R. karinthandani, R. melanoleucus, and R. sanguineus, seemingly representing a novel bilobate morphology. One species, U. bhupathyi, exhibits a novel, bulbous morphology, but this may be an artifact of preservation. The hemipenes of the Uropeltidae and their sister group Cylindrophiidae resemble some typhlopoid blindsnakes more than their henophidian relatives such as pythons and boas. Whether this is due to convergence related to microhabitat, a form of sexual selection unrelated to ecomorphology, or symplesiomorphy from an ancestral snake morphology is unclear. Gross hemipenial morphology can now serve to diagnose uropeltids to the genus level or species group, though more data and comparative series are needed to determine whether other characters, such as the number and location of spines, can potentially differentiate taxa at finer scales.

Shallow marine ecosystem collapse and recovery during the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM), the most well-studied transient hyperthermal event in Earth history, is characterized by prominent and dynamic changes in global marine ecosystems. Understanding such biotic responses provides valuable insights into future scenarios in the face of anthropogenic warming. However, evidence of the PETM biotic responses is largely biased towards deep-sea records, whereas shallow-marine evidence remains scarce and elusive. Here we investigate a shallow-marine microfaunal record from Maryland, eastern United States, to comprehensively document the shallow-marine biotic response to the PETM. We applied birth-death modeling to estimate the local diversity dynamics, combined with evaluation of time-variable preservation artifacts. We discovered strong increase of species disappearance and appearance predating the onset and at the final recovery phase of the PETM, respectively. Our paleoecological analyses indicate that bathymetric habitat compression due to extreme warmth and oxygen minimum zone expansion caused shallow-marine benthic species extirpation and ecosystem perturbation during the PETM; and that rapid recovery and diversification followed the PETM disaster, thus contributing new understanding to the shallow-marine biotic changes in a broad context of global warming. • Local extinction event predates the Paleocene-Eocene Thermal Maximum (PETM) onset. • Rapid local diversification occurred when the PETM anomalies terminated. • A clear perturbation-recovery pattern of the shallow-marine ecosystem across PETM. • Habitat compression by warming and deoxygenation led to local PETM extinction. • Biodiversity loss by hyperthermal events may be irreversible.

Old Brains in Alcohol: The Usability of Legacy Collection Material to Study the Spider Neuroarchitecture

Natural history collections include rare and significant taxa that might otherwise be unavailable for comparative studies. However, curators must balance the needs of current and long-term research. Methods of data extraction that minimize the impact on specimens are therefore favored. Micro-CT has the potential to expose new character systems based on internal anatomy to taxonomic and phylogenetic analysis without dissection or thin sectioning for histology. However, commonly applied micro-CT protocols involve critical point drying, which permanently changes the specimen. Here, we apply a minimally destructive method of specimen preparation for micro-CT investigation of spider neuroanatomy suitable for application to legacy specimens in natural history collections. We used two groups of female spiders of the common species Araneus diadematus—freshly captured (n = 11) vs. legacy material between 70 and 90 years old (n = 10)—to qualitatively and quantitatively assess the viability of micro-CT scanning and the impact of aging on their neuroarchitecture. We statistically compared the volumes of the supraesophageal ganglion (syncerebrum) and used 2D geometric morphometrics to analyze variations in the gross shape of the brain. We found no significant differences in the brain shape or the brain volume relative to the cephalothorax size. Nonetheless, a significant difference was observed in the spider size. We considered such differences to be explained by environmental factors rather than preservation artifacts. Comparison between legacy and freshly collected specimens indicates that museum specimens do not degrade over time in a way that might bias the study results, as long as the basic preservation conditions are consistently maintained, and where lapses in preservation have occurred, these can be identified. This, together with the relatively low-impact nature of the micro-CT protocol applied here, could facilitate the use of old, rare, and valuable material from collections in studies of internal morphology.

Evaluating preservation bias in the continental growth record against the monazite archive

Abstract Most recent models of continental growth are based on large global compilations of detrital zircon ages, which preserve a distinctly episodic record of crust formation over billion-year timescales. However, it remains unclear whether this uneven distribution of zircon ages reflects a true episodicity in the generation of continental crust through time or is an artifact of the selective preservation of crust isolated in the interior of collisional orogens. We address this issue by analyzing a new global compilation of monazite ages (n >100,000), which is comparable in size, temporal resolution, and spatial distribution to the zircon continental growth record and unambiguously records collisional orogenesis. We demonstrate that the global monazite and zircon age distributions are strongly correlated throughout most of Earth history, implying a link between collisional orogenesis and the preserved record of continental growth. Our findings support the interpretation that the continental crust provides a preservational, rather than generational, archive of crustal growth.

Yarravia oblonga Lang & Cookson, 1935 emended, from the Lower Devonian of Victoria, Australia

Yarravia oblonga is emended here and adds to our knowledge of floral diversity during the late Silurian and Early Devonian of central Victoria, Australia. Examination of specimens and analysis with light microscopy have revealed its defining characteristics as a slender elongate fructification, with most of the dichotomies in the fructification confined to the sterile axes. The sporangia of Y. oblonga are located centrally with sterile axes on the outside curving up and over the apices. The original diagnosis of a synangium is discounted as it was an artefact of preservation, and Hedeia is now considered a heterotypic synonym of Yarravia, with the latter taking priority. Furthermore, the branching pattern of Yarravia is simple and demonstrates that it does not belong with the ‘trimerophyte grade’. The presence of Yarravia in South China is of palaeophytogeographical importance, as it suggests some exchange between the two regions or is evidence of convergent evolution. Fearghus R. McSweeney* [fearghus.mcsweeney@rmit.edu.au] School of Science, RMIT University, Swanston Street, Melbourne 3000, Australia; Jeff Shimeta [jeff.shimeta@rmit.edu.au] School of Science, RMIT University, Swanston Street, Melbourne 3000, Australia; John St. J. S. Buckeridge [john.buckeridge@rmit.edu.au] Earth & Oceanic Systems Group, RMIT University, GPO Box 2476, Melbourne, Australia.

Нематериальное культурное наследие как предмет дискурса культурологической школы Беларуси

The article substantiates the need for theoretical and methodological study and practical activities of socio-cultural institutions to identify, valorise objects of intangible cultural heritage (hereinafter referred to as ICH) created by the world community in order to protect, preserve and include it in the modern cultural space. The author considers various scientific approaches to attribution of artifacts of national culture, their patrimonialization and inclusion in the “State List of the Republic of Belarus” and “Representative List of the Intangible Cultural Heritage of Humanity” of UNESCO. It is noted that the Belarusian School of Cultural Studies conducts significant scientific and practical activities to understand the role and place of ICH in the modern globalizing world. The essence of the problem lies in the different approach of culturologists, museologists, historians to the attribution, valerization of objects of intangible cultural heritage, which complicates the activities of the state and the public to preserve and represent it. The purpose of the article is to outline the actualization of the problem of the preservation of ICT in the context of globalization both in Belarus and in Ukraine, to combine the efforts of Ukrainian and Belarusian cultural scientists to determine scientific approaches to the study of ICT objects and to develop recommendations for practitioners in the socio-cultural sphere who should directly deal with the protection and preservation artifacts of cultural heritage.

Worldwide Distribution Patterns of the Planktonic Shelled Protists Radiolaria (Polycystina) and Foraminifera: Similarities and Contrasts

Planktonic Foraminifera and Polycystina (Radiolaria) depict roughly similar—but not identical—worldwide distribution patterns. Discrepancies affect both cold- and warmwater areas, as well as the latitudinal profile of species richness, which peaks at the equator in Radiolaria, but in the subtropics in Foraminifera. Some differences are probably due to group-specific dissimilarities, but preservational and methodological artifacts play a key role.

A comparison between Zooglider and shipboard net and acoustic mesozooplankton sensing systems

Abstract Some planktonic patches have markedly higher concentrations of organisms compared to ambient conditions and are <5 m in thickness (i.e. thin layers). Conventional net sampling techniques are unable to resolve this vertical microstructure, while optical imaging systems can measure it for limited durations. Zooglider, an autonomous zooplankton-sensing glider, uses a low-power optical imaging system (Zoocam) to resolve mesozooplankton at a vertical scale of 5 cm while making concurrent physical and acoustic measurements (Zonar). In March 2017, Zooglider was compared with traditional nets (MOCNESS) and ship-based acoustics (Simrad EK80). Zoocam recorded significantly higher vertically integrated abundances of smaller copepods and appendicularians, and larger gelatinous predators and mineralized protists, but similar abundances of chaetognaths, euphausiids, and nauplii. Differences in concentrations and size-frequency distributions are attributable to net extrusion and preservation artifacts, suggesting advantages of in situ imaging of organisms by Zooglider. Zoocam detected much higher local concentrations of copepods and appendicularians (53 000 and 29 000 animals m−3, respectively) than were resolvable by nets. The EK80 and Zonar at 200 kHz agreed in relative magnitude and distribution of acoustic backscatter. The profiling capability of Zooglider allows for deeper high-frequency acoustic sampling than conventional ship-based acoustics.

Longitudinal study of rat volar fat pad fixation and ethanol storage: implications for the use of fluid-preserved specimens in morphological studies.

Museum fluid collections preserve important biological specimens for study. Tissues are often fixed in 10% buffered formalin to halt metabolic activities and transferred to a solution of ethanol for long-term storage. This process, however, forces water from the tissues and has been shown to alter the morphology of preserved specimens in ways that may influence the biological interpretation of results. The degree to which fluid preservation alters morphology is linked to multiple biological factors, such as tissue size and composition, and should therefore be examined prior to functional analysis. This study is undertaken as part of a more inclusive examination of mammalian volar morphology. A sample of five adult male and five adult female rats (Rattus norvegicus) was utilized to evaluate longitudinal changes in the dimensions of the volar pads across fixation in 10% buffered formalin and preservation in 70% ethanol for 1 year. No significant changes to the measured dimensions of the rat volar pads were present across stages of fixation and preservation, and no significant interactions of specimen size or sex were noted. These findings indicate that small mammalian volar pads that have been fixed in 10% buffered formalin and stored in 70% ethanol are appropriate for morphological study using the measurements described here without corrective algorithms. This finding is rare among preservation studies but highlights the variability of tissue behavior during chemical preservation and the necessity of preliminary investigations of preservation artifacts. Concurrence here between the preserved and unpreserved samples is likely related to the anhydrous nature of the volar pads and the supporting skeletal structure, and their confined position between major joints of the hands and feet.

The largest flying reptile from the Crato Formation, Lower Cretaceous, Brazil

ABSTRACTThe Early Cretaceous deposits of the Araripe Basin in northeast Brazil has yielded numerous vertebrate fossils, in which pterosaurs are the predominant tetrapods. Almost all specimens of this extinct group of flying reptiles recovered from this basin come from two stratigraphic units, the Crato and Romualdo Formations, with the pterosaurs from the former being usually small to middle-sized and large individuals (with a maximized wingspan over 5 m) being only found in the latter. Here we report on a new specimen (MPSC R 1221) composed of a partial right wing, which is the largest pterosaur discovered from the Crato Formation so far, having an estimated maximized wingspan of 5.5 m. Despite the incompleteness of this material, MPSC R 1221 can be referred to the Anhangueridae based on the length ratio between the metacarpal IV and the first wing phalanx. According to the osteohistological study and the degree of fusion, MPSC R 1221 represents a sub-adult individual, showing that the animal had not reached the maximum size before its death. The present study shows that large-sized pterosaurs were also present in the Crato Formation and that their rarity might be an artefact of preservation.

Low oxygen and argon in the Neoproterozoic atmosphere at 815 Ma

The evolution of Earth's atmosphere on >106-yr timescales is tied to that of the deep Earth. Volcanic degassing, weathering, and burial of volatile elements regulates their abundance at the surface, setting a boundary condition for the biogeochemical cycles that modulate Earth's atmosphere and climate. The atmosphere expresses this interaction through its composition; however, direct measurements of the ancient atmosphere's composition more than a million years ago are notoriously difficult to obtain. Gases trapped in ancient minerals represent a potential archive of the ancient atmosphere, but their fidelity has not been thoroughly evaluated. Both trapping and preservation artifacts may be relevant. Here, I use a multi-element approach to reanalyze recently collected fluid-inclusion data from halites purportedly containing snapshots of the ancient atmosphere as old as 815 Ma. I argue that those samples were affected by the concomitant trapping of air dissolved in brines and contaminations associated with modern air. These artifacts lead to an apparent excess in O2 and Ar. The samples may also contain signals of mass-dependent fractionation and biogeochemical cycling within the fluid inclusions. After consideration of these artifacts, this new analysis suggests that the Tonian atmosphere was likely low in O2, containing ≤10% present atmospheric levels (PAL), not ∼50% PAL as the data would suggest at face value. Low concentrations of O2 are consistent with other geochemical constraints for this time period and further imply that the majority of Neoproterozoic atmospheric oxygenation occurred after 815 Ma. In addition, the analysis reveals a surprisingly low Tonian Ar inventory—≤60% PAL—which, if accurate, challenges our understanding of the solid Earth's degassing history. When placed in context with other empirical estimates of paleo-atmospheric Ar, the data imply a period of relatively slow atmospheric Ar accumulation in the Paleo- and Meso-Proterozoic, followed by extensive degassing in the late Neoproterozoic or early Cambrian, before returning to a relatively quiescent state by the Devonian. This two-step structure resembles that for the evolution of atmospheric O2, hinting at a common driving force from the deep Earth. Some caution is warranted, however, because still more enigmatic contaminations than the ones presented here may be relevant. Gases trapped in minerals may offer important constraints on the evolution of Earth's surface, climate, and atmosphere, but potential contaminations and other confounding factors need to be considered carefully before these records can be considered quantitative.

Two rare taxa from the type area of the Devonian, south-west England

The rarity of certain taxa in the type Devonian, south-west England, may be real, but it is probably, in part, an artefact of preservation. In part this is a product of Variscan deformation, but disarticulation of multi-element skeletons into minute plates must also be a contributory factor. Echinoids are rare from these deposits and were hitherto limited to the Upper Devonian. A single radiole (=spine) from the Middle Devonian (Givetian) Lummaton Shell Beds, Torquay Limestone Formation, is referred to echinoid sp. indet. Although stromatoporoids are common in these same beds, true sponges were hitherto unknown. In the same rock specimen, a moderately well preserved siliceous spicule is referred to octactinellid sp. indet.

The Osteology and Phylogenetic Position of Luperosuchus fractus (Archosauria: Loricata) from the Latest Middle Triassic or Earliest Late Triassic of Argentina

Large archosaurs from the early part of the archosaur radiation are exceedingly rare and with few exceptions, most of these remains consist of fragmentary postcrania. We redescribe the fragmentary skull of Luperosuchus fractus from the early Middle—Late Triassic Chañares Formation of Argentina, assign newly discovered fragments from the original excavation to the same individual, and analyze its phylogenetic affinities. The dorsally convex and mediolaterally compressed anterior portion of the nasal (= ‘Roman-nose’), convex and circular knob on the dorsolateral margin of the postorbital, and a long anterior process of the prefrontal that fails to extend to the anterior end of the frontal are considered autapomorphies of Luperosuchus. The elongated gap between the nasal and maxilla is likely an artifact of preservation and this prompted a critical reevaluation of the supposed openings in the anterior portion of the skull of other suchians. We confirm that Luperosuchus is a loricatan (composed mostly of the taxa classically termed as ‘rauisuchians’) using a well sampled phylogeny and find a close relationship with the other large southwestern Pangean forms, Prestosuchus chiniquensis and Saurosuchus galilei. We also show that the holotype of Luperosuchus is the only known specimen of the taxon and all other previously referred material cannot be assigned with confidence to it.

Earliest Onychophoran in Amber Reveals Gondwanan Migration Patterns

The anomalous occurrence of supposedly Gondwanan taxa in Laurasian-derived regions remains an intriguing chapter of paleobiogeographical history. Representatives of Peripatidae, a major subgroup ofvelvet worms (Onychophora), show a disjointed distribution in the neotropics, tropical Africa, and Southeast Asia, the latter being the only landmass previously associated with Laurasia [1, 2]. The arrival of these animals in Southeast Asia is explained bytwoalternative, albeit not mutually exclusive, hypotheses: an early migration via Europe before continental drift (Eurogondwana hypothesis) or transportation via insular India during the Cretaceous and Paleogene ("out-of-India" hypothesis) [3-6]. The latter hypothesis is based on a single extant species of Peripatidae,Typhloperipatus williamsoni, in India. †Cretoperipatus burmiticus from Myanmar is the oldest fossil onychophoran found in amber [7], dating to sometime between the two proposed scenarios, and hence crucial for clarifying how Gondwanan lineages of these low-vagility animals reached Southeast Asia (see also Supplemental Information). Based on the anatomical reconstruction of †C.burmiticus using synchrotron radiation-based X-ray microtomography (SRμCT) and comparisons with extant taxa, we resolved this fossil species within Onychophora, particularly within Peripatidae, with T.williamsoni as its closest extant relative. This suggests that an early Eurogondwanan migration of peripatids was the most likely event, as Burmese amber is too old to becompatible with the out-of-India hypothesis. Moreover, peripatids probably colonized India only recently from Myanmar, refuting the putative Gondwanan relict status of Indian onychophorans. Finally, preservation artifacts identified in the novel amber material might have a major impact on studies of onychophoran stem and/or crown groups.

Long-term Isopropanol Storage Does Not Alter Fish Morphometrics

Since the discovery of spirit-based preservation, scientists have based innumerable studies of systematics, anatomy, development, biogeography, evolutionary biology, and ecomorphology on fluid specimens held by the world's natural history collections. Though alcohol preservation can alter specimen measurements through dehydration and shrinkage, the magnitude of this problem over decadal timescales has never been estimated. If substantial, long-term preservational effects could compromise studies that depend on the comparability of morphometrics drawn from specimens collected at different times unless the artifacts were explicitly controlled. To evaluate the importance of these potential artifacts, we obtained geometric morphometric data from series of four common fish species collected from the Willamette River drainage over the last 70 years and preserved in the Oregon State Ichthyology Collection in 50% isopropanol after formalin fixation. Most regressions of principal component axes against date of collection revealed no directional trends in specimen morphology, and the two significant regressions lose significance when recent collections from the ecologically distinctive river main stem are excluded. We conclude that specimen shrinkage occurs shortly after preservation and does not exacerbate over time and that much of the observed morphological variation in our sample likely stems from habitat differences among collecting localities. Thus, morphological studies can continue to compare specimens collected over decadal timespans to answer questions about the ecological, evolutionary, and biogeographic causes of morphological variation with minimal concern for major preservational artifacts caused by long-term alcohol storage.