Primitive life habits and adaptive significance of the pelecypod form

Paleobiology ◽  
1976 ◽  
Vol 2 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Michael J. S. Tevesz ◽  
Peter L. McCall
Keyword(s):  
Small Body ◽  
Relative Size ◽  
Mantle Cavity ◽  
Shell Morphology ◽  
Suspension Feeding ◽  
Suspension Feeders ◽  
Body Sizes ◽  
Mode Of Life ◽  
Life Habits ◽  
Soft Bottoms

The typical pelecypod form, long thought to be primitively adaptive to burrowing, is likely to have been originally adaptive to a suspension feeding, epifaunal, possibly crawling mode of life. At small body size (< 1 cm), pelecypods possessing typical burrowing features can function as epifaunal crawlers. Pelecypods arose at small body sizes and are part of a molluscan evolutionary sequence in which relative size of the mantle cavity increased to accommodate a few large gills specialized for suspension feeding.Acquisition of a bivalved shell by ancestral epifaunal suspension feeders may have offered protection from sediment clogging on soft bottoms, additional control over the direction, volume, and rate of water flow through the mantle cavity, more effective protection from predators, and better short-term control of the internal environment. Consideration of invertebrate groups analogous to the pelecypods (Branchiopoda, Cladocera, Ostracoda, Phyllocarida) support the view that the bivalve condition is primarily an adaptation for suspension feeding and predator avoidance in benthic environments.The earliest known pelecypod, Fordilla troyensis Barrande, was not necessarily infaunal just because it had features similar to much larger, Recent burrowers. The size, shell morphology and environment of preservation of F. troyensis all suggest that it is reasonable to envision Cambrian pelecypods as epifaunal suspension feeders, possibly crawling on sedimentary bottoms. Moreover, the sudden Ordovician expansion of pelecypods and increase in individual size may be explained as a result of invasion of the infaunal adaptive zone.

Hábitos de vida dos Gastropoda e Bellerophontida da formação Maecuru, Devoniano Médio, Bacia do Amazonas, Brasil

2007 ◽  
Vol 30 (1) ◽  
pp. 197-203
Author(s):  
Luiza Corral Martins de Oliveira Ponciano ◽  
Deusana Maria da Costa Machado ◽  
Ana Carolina Gelmini de Faria ◽  
Ana Carolina Maciel ◽  
Juliana Matos ◽  
...  
Keyword(s):  
High Mobility ◽  
The Other ◽  
Nutrient Source ◽  
Cross Sectional ◽  
Suspension Feeders ◽  
Fine Grained ◽  
Mode Of Life ◽  
Life Habits ◽  
Shallow Seas ◽  
High Diversity

The Maecuru Formation comprises the Devonian-Carboniferous sedimentary sequence of Amazonas Basin and consists of fluvialdeltaics to neritics sandstones and pelites layers. Its fossiliferous sediments (the uppermost part of the Lontra Member) consists of hummocky cross-stratified fine-grained to very coarse sandstones beds.With the purpose of adding more information about the palaeoecology of The Maecuru Formation fossils, the life habits of gastropods and bellerophontids were inferred based on functional analysis and similarities with the living forms. The more significant features used were: (1) total frontal cross-sectional area, (2) height and relative positions of pressure point and center of gravity, (3) apertural margin morphology, (4) kind of symmetry and (5) surface smoothness. The species Platyceras (Orthonychia) steinmanni; Platyceras (Tumbophalus) hartti; Platyceras (Platyostoma) darwini; Platyceras (Platyostoma) (?) agassizi; Platyceras (Orthonychia) meerwarthi; Platyceras (Orthonychia) gracilis; Platyceras (Tumbophalus) coutoanus; "Platyceras" tschernischewi; "Platyceras" subconicum; "Platyceras" (Ortonychia) hussaki; "Platyceras" (Ortonychia) whitii; "Platyceras" (Ortonychia) whitii var. curua and "Platyceras" symmetricum var. maecuruensis represent the epifaunal gastropods with low mobility (coprophagous/suspension feeders) of the Maecuru Formation, living symbiotically directly over the anus of a crinoid or nearby. This coprophagous mode of life was probably a non-obligate relationship, because only the closest organisms will get all the advantages of using the crinoid host as a nutrient source. The others adult platyceratids would have a broader feeding repertoire, like as suspension feeders. The bellerophonts Plectonotus (Plectonotus) derbyi, Plectonotus (?) (Plectonotus) salteri e Bucanella reissi would have an epifaunal medium to high mobility, showing a predator habit preferably. On the other hand Bucania freitasi, Ptomatis forbesi and Bellerophon steltzneri showed morphologies compable to a grazer habit with medium mobility. This relative high diversity of gastropods and bellerophonts corroborates the environment of medium and inner shelf inferred for the Maecuru Formation among the others macrofossils, since the majority of Paleozoic fauna of gastropods were typically from shallow seas.

scholarly journals Parallel evolutionary trajectories underlie the origin of giant suspension-feeding whales and bony fishes

2011 ◽  
Vol 279 (1730) ◽  
pp. 944-951 ◽  
Author(s):  
Matt Friedman
Keyword(s):  
Strong Support ◽  
Sister Group ◽  
Lower Jurassic ◽  
Suspension Feeding ◽  
Baleen Whales ◽  
Suspension Feeders ◽  
Lack Of Information ◽  
Bony Fishes ◽  
Body Sizes ◽  
Posidonia Shale

Giant suspension feeders such as mysticete whales, basking and whale sharks, and the extinct (indicated by ‘†’) †pachycormiform teleosts are conspicuous members of modern and fossil marine vertebrate faunas. Whether convergent anatomical features common to these clades arose along similar evolutionary pathways has remained unclear because of a lack of information surrounding the origins of all groups of large-bodied suspension feeders apart from baleen whales. New investigation reveals that the enigmatic ray-finned fish † Ohmdenia , from the Lower Jurassic (Toarcian, 183.0–175.6 Ma) Posidonia Shale Lagerstätte , represents the immediate sister group of edentulous †pachycormiforms, the longest lived radiation of large vertebrate suspension feeders. † Ohmdenia bisects the long morphological branch leading to suspension-feeding †pachycormiforms, providing information on the sequence of anatomical transformations preceding this major ecological shift that can be compared to changes associated with the origin of modern mysticetes. Similarities include initial modifications to jaw geometry associated with the reduction of dentition, followed by the loss of teeth. The evolution of largest body sizes within both radiations occurs only after the apparent onset of microphagy. Comparing the fit of contrasting evolutionary models to functionally relevant morphological measurements for whales and †pachycormiform fishes reveals strong support for a common adaptive peak shared by suspension-feeding members of both clades.

scholarly journals Hábitos de vida da associação "Schuchertella" agassizi - Pthychopteria eschwegei, formação Maecuru, Devoniano, Bacia do Amazonas, Brasil

2007 ◽  
Vol 30 (1) ◽  
pp. 135-144
Author(s):  
Luiza Corral Martins de Oliveira Ponciano ◽  
Deusana Maria da Costa Machado
Keyword(s):  
Benthic Invertebrate ◽  
Suspension Feeder ◽  
Shallow Marine ◽  
Suspension Feeders ◽  
Deposit Feeders ◽  
Mode Of Life ◽  
Life Habits ◽  
Coarse Sediments ◽  
Rivers State ◽  
Normal Salinity

The fossils studied came from outcrops of the Maecuru and Curuá rivers, State of Pará, belonging to the upper strata of the Maecuru Formation, Eifelian age. In this formation, two associations of marine benthic invertebrate can be identified, each inferring a distinct paleoenvironment. The association analyzed occurs in medium and coarse sandstones and shows "Schuchertella" agassizi and Ptychopeteria eschwegei as predominant organisms. It was idnetified 12 species of brachiopods, 20 species of bivalves, 12 of trilobites, 8 of gastropods, 6 of bellerophonts, 3 of crinoids and 3 of tentaculitids in this association. Brachiopods are the most abundant organisms, responsible for approximately 50% of it, followed by tentaculitids and bivalves. Trilobites, gastropods and bellerophonts sum less than 10% of the aforementioned association. Crinoids were not included in the quantitative analysis because they are only found as calicinal plates and disarticulated column disks. The brachiopods showed, through their morphofunctional characteristics, suspension feeders recumbent (free-lying) epifaunal life habit or a pedicle attached mode of life. The bivalves showed a predominant suspension feeder semiinfaunal habit, attached by byssus threads to the substratum, and an infaunal mode of life. All the trilobites showed a predator/scavenger and vagile epifaunal habit. The epifaunal platyceratids represents the gastropods with low mobility (coprophagous/suspension feeders). The bellerophonts showed an epifaunal highly/medium mobility and grazing/predator habit. The tentaculitids having a semi-infaunal, suspension feeder habit. The suspension feeder forms (brachiopods, bivalves and tentaculitids) account for over 90% of the organisms, with the remaining percentage distributed among the predator/scavenger (trilobites), coprophagous/suspension feeders (gastropods), grazers/ predators (bellerophonts) and deposit feeders (rare bivalves). The predominance of suspension feeder forms corroborates the environment inferred for the association, since suspension feeders adapt more easily to rough waters and coarse sediments. The life habits showed adaptations concerning a shallow marine environment with agitated waters, well-oxygenated, normal salinity and moderate temperatures.

scholarly journals Long-term patterns of body mass and stature evolution within the hominin lineage

2017 ◽  
Vol 4 (11) ◽  
pp. 171339 ◽  
Author(s):  
Manuel Will ◽  
Adrián Pablos ◽  
Jay T. Stock
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Homo Sapiens ◽  
Small Body ◽  
Relative Size ◽  
Size Variation ◽  
Adaptive Strategy ◽  
Middle Pleistocene ◽  
Body Sizes

Body size is a central determinant of a species' biology and adaptive strategy, but the number of reliable estimates of hominin body mass and stature have been insufficient to determine long-term patterns and subtle interactions in these size components within our lineage. Here, we analyse 254 body mass and 204 stature estimates from a total of 311 hominin specimens dating from 4.4 Ma to the Holocene using multi-level chronological and taxonomic analytical categories. The results demonstrate complex temporal patterns of body size variation with phases of relative stasis intermitted by periods of rapid increases. The observed trajectories could result from punctuated increases at speciation events, but also differential proliferation of large-bodied taxa or the extinction of small-bodied populations. Combined taxonomic and temporal analyses show that in relation to australopithecines, early Homo is characterized by significantly larger average body mass and stature but retains considerable diversity, including small body sizes. Within later Homo , stature and body mass evolution follow different trajectories: average modern stature is maintained from ca 1.6 Ma, while consistently higher body masses are not established until the Middle Pleistocene at ca 0.5–0.4 Ma, likely caused by directional selection related to colonizing higher latitudes. Selection against small-bodied individuals (less than 40 kg; less than 140 cm) after 1.4 Ma is associated with a decrease in relative size variability in later Homo species compared with earlier Homo and australopithecines. The isolated small-bodied individuals of Homo naledi ( ca 0.3 Ma) and Homo floresiensis ( ca 100–60 ka) constitute important exceptions to these general patterns, adding further layers of complexity to the evolution of body size within the genus Homo . At the end of the Late Pleistocene and Holocene, body size in Homo sapiens declines on average, but also extends to lower limits not seen in comparable frequency since early Homo .

The functional and adaptive morphology of the deep-sea species of the family limopsidae (Bivalvia: arcoida) from the atlantic

1980 ◽  
Vol 291 (1045) ◽  
pp. 77-125 ◽  
Keyword(s):  
Deep Sea ◽  
Food Production ◽  
Small Body ◽  
Mantle Cavity ◽  
Suspension Feeding ◽  
Minor Variation ◽  
The Family ◽  
Dorsal Portion ◽  
Different Populations ◽  
Adaptive Morphology

The functional and adaptive morphology of six species of the genus Limopsis from deep water of the Atlantic is investigated and the following species and subspecies are described: L. aurita, L. surinamensis (new species), L. tenella, L. minuta, L. cristata cristata, L. cristata affinis, L. cristata intermedia (new subspeices), L. cristata lanceolata (new subspecies), L. galathea . Species of the genus Limopsis are among the relatively few suspension-feeding bivalves of the deep sea. The genus is not represented in shelf faunas. It is byssate, but the species described here show a change in habit from the exobyssate to the endobyssate condition and a corresponding reduction in the number and coarseness of the byssus threads produced. While the morphology of the species is similar in all the species described, differences being restricted to minor variation in the gills and palps, the viscera are confined to a small dorsal portion of the mantle cavity. Thus, while small body size is related to the paucity of food, production of a large thick shell may require a relatively small proportion of the energy input and yet confer advantage possibly in protection and in feeding mechanism. Eggs are relatively few and of a size indicating that the larvae are planktonic but non-feeding. The widely occurring species L. tenella shows differences in the shell characters of different populations. In L. cristata variation is such that it has been possible to describe subspecies.

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

scholarly journals Seasonal maturation of Glypthelmins vitellinophilum (Trematoda: Digenea) in Lysapsus limellus (Anura: Pseudidae) from an Argentinian subtropical permanent pond

2006 ◽  
Vol 66 (1a) ◽  
pp. 85-93 ◽  
Author(s):  
M. I. Hamann
Keyword(s):  
Body Length ◽  
Developmental Stages ◽  
Small Body ◽  
Stage Iv ◽  
The Body ◽  
Climatic Fluctuations ◽  
Parasite Stage ◽  
Permanent Pond ◽  
Body Sizes ◽  
The Relationship

From December 1995 to November 2000, the seasonal maturation of Glypthelmins vitellinophilum Dobbin, 1958, in its definitive host, the frog Lysapsus limellus Cope, 1862, was studied in a subtropical permanent pond in northeastern Argentina. The objectives of this study were: 1) to determine the infrapopulation dynamics of the parasite, analyzing the seasonal maturation cycle throughout the years; and 2) to examine the relationship between the intensity of trematode infection in different developmental stages (recruitment, growth and maturation) and the host's body length. Of a total of 1,400 frogs examined over 60 months (5 years), 38% were found to be infected with G. vitellinophilum, and the intensity of infection was 1-15 trematodes per frog. Specimens of G. vitellinophilum were present in L. limellus throughout the years, but did not show a pronounced seasonal maturation cycle. Possible reasons for these findings are discussed with reference to climatic fluctuations and biotic factors. The infective period of the parasite (stage I) occurred in summer, autumn and spring, coinciding with the time each frog cohort appeared. These infections were found principally in small body sizes (classes 1 and 2) of L. limellus. Juvenile and nongravid specimens of worms (stage II and III) were found in frogs of different body sizes throughout the period of investigation. Gravid specimens of the parasite (stage IV) were generally recorded in autumn, winter and spring, mainly in the bodies of larger frogs. The body length of Trematodes in stages I and IV was significantly and positively correlated with that of the frogs.

scholarly journals Aquatic insects are dramatically underrepresented in genomic research

2020 ◽  
Author(s):  
Scott Hotaling ◽  
Joanna L. Kelley ◽  
Paul B. Frandsen
Keyword(s):  
Aquatic Insects ◽  
Small Body ◽  
Aquatic Insect ◽  
Freshwater Ecosystems ◽  
Future Research ◽  
Insect Genome ◽  
Terrestrial Insect ◽  
Body Sizes ◽  
Terrestrial Insects ◽  
Insight Into

AbstractAquatic insects comprise 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. Yet aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ∼9 terrestrial insect genomes. Instead, ∼24 terrestrial insect genomes have been sequenced for every aquatic insect genome. This discrepancy is even more dramatic if the quality of genomic resources is considered; for instance, while no aquatic insect genome has been assembled to the chromosome level, 29 terrestrial insect genomes spanning four orders have. We argue that a lack of aquatic insect genomes is not due to any underlying difficulty (e.g., small body sizes or unusually large genomes) yet it is severely hampering aquatic insect research at both fundamental and applied scales. By expanding the availability of aquatic insect genomes, we will gain key insight into insect diversification and empower future research for a globally important taxonomic group.Simple SummaryAquatic insects comprise 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. Yet aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ∼9 terrestrial insect genomes. Instead, ∼24 terrestrial insect genomes have been sequenced for every aquatic insect genome. We argue that the limited availability of aquatic insect genomes is not due to practical limitations—e.g., small body sizes or overly complex genomes—but instead reflects a lack of research interest. We call for targeted efforts to expand the availability of aquatic insect genomic resources to gain key molecular insight into insect diversification and empower future research.

scholarly journals Polymorphy and extinction of the Late Cretaceous burrowing shrimp Protocallianassa faujasi and first record of the genera Corallianassa and Calliax (Crustacea, Decapoda, Thalassinoidea) from the Cretaceous

2001 ◽  
Vol 70 (2) ◽  
pp. 85-98 ◽  
Author(s):  
Krista Swen ◽  
René H.B. Fraaije ◽  
Gijsbert J. van der Zwaan
Keyword(s):  
New Species ◽  
First Record ◽  
Suspension Feeding ◽  
Feeding Mode ◽  
Male And Female ◽  
Immature Male ◽  
Type Area ◽  
Mode Of Life ◽  
Burrow Morphology

A biometric study of chelae of the burrowing shrimp Protocallianassa faujasi ( Desmarest, 1822), from the late Maastrichtian of the Maastrichtian type area, The Netherlands, has revealed three morphotypes. These types are interpreted as sexual dimorphs (male and female) and earliest ecdysis stages (immature male). Among the studied material are fifteen specimens of a new Cretaceous callianassid, Corallianassa acucurvata new species, one specimen provisionally assigned to the genus Calliax and a callianassid from the Danian. Burrows preserving callianassid chelae in situ are discussed. Based on burrow morphology a suspension feeding mode of life for P.faujasi is inferred, whereas C. acucurvata n. sp. probably was an active omnivorous analogue of its closest Recent relatives. The extinction of P. faujasi in the Meerssen Member appears to correspond to the increase in seagrass vegetation. The Protocallianassa-Corallianassa faunal changeover took place about 100,000 yrs before the K/T boundary in this region.

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