The shell as a recording device: growth record and shell ultrastructure of Lampsilis radiata radiata (Pelecypoda: Unionidae)

Growth records retained in the shell of Lampsilis radiata radiata and shell ultrastructure were examined in a population from Lake Champlain, Vermont, U.S.A. Maximum size was 75 mm as measured from the umbo to the farthest margin. Ages were obtained by counting annual bands, and growth plots were constructed. By knowing the amount grown by individuals of the same age in the same year, the years 1975 and 1977 were identified as poor for growth of younger individuals. Light micrographs of shell thin sections showed macroscopic annual lines, and microscopic and ultrastructural lines. Ultrastructural lines were visible within macroscopic lines. Scanning electron micrographs of etched sections clarified the light micrographs and allowed recognition of two damage-response structures embedded within the nacreous layer in the umbonal region: adventitious conchiolin and prismatic crystals. Theories of growth line formation are presented. Shell growth appears to follow an alternating cycle of protein deposition as organic matrices followed by CaCO3 secretion into the matrices. The Lutz–Rhoads theory of growth line formation, based on alternating periods of aerobic and anaerobic metabolism, was examined in detail and found unsuitable for this species.

Download Full-text

The Composition of Tidally Deposited Growth Lines in the Shell of the Edible Cockle, Cerastoderma Edule

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400052425 ◽

1985 ◽

Vol 65 (3) ◽

pp. 573-581 ◽

Cited By ~ 14

Author(s):

Margaret R. Deith

Keyword(s):

Marine Invertebrates ◽

Biological Clock ◽

Growth Line ◽

Line Formation ◽

Cerastoderma Edule

The shells of marine invertebrates grow incrementally (Wilbur, 1972). When a section of shell is observed under the microscope, the increments are often visible, separated by fine lines (Fig. 1). Studies of these phenomena have focused chiefly on the periodicity of increment and growth-line formation, principally because of its geological or archaeological application as a ‘biological clock’ (e.g. Wells, 1963; Koike, 1973).

Download Full-text

Longbone histology of the Tendaguru sauropods: implications for growth and biology

Paleobiology ◽

10.1666/0094-8373(2000)026<0466:lhotts>2.0.co;2 ◽

2000 ◽

Vol 26 (3) ◽

pp. 466-488 ◽

Cited By ~ 171

Author(s):

P. Martin Sander

Keyword(s):

Bone Tissue ◽

Growth Pattern ◽

Sexual Maturity ◽

Sampling Technique ◽

Maximum Size ◽

Upper Jurassic ◽

Growth Line ◽

Fossil Bone ◽

Growth Series ◽

Size At Sexual Maturity

A new sampling technique for fossil bone (coring with a 5/8″ bit) was used to sample longbones of all four sauropod genera from the Upper Jurassic Tendaguru beds of Tanzania for paleohistological study. Brachiosaurus and Barosaurus are represented by growth series of humeri and femora, while Dicraeosaurus could be sampled in fewer specimens and only one bone of Janenschia was available. Although all samples are dominated by fibrolamellar bone tissue, taxa can be distinguished by the degree and nature of bone remodeling and the presence and spacing of a peculiar kind of growth line (here termed “polish lines”). In addition, Barosaurus bone revealed two types of histology, tentatively interpreted as sexual morphs. The Tendaguru sauropods show a common growth pattern in which growth is determinate but sexual maturity is achieved well before maximum size is reached. For Brachiosaurus and Barosaurus, size at sexual maturity can be estimated and was reached at about 40% and 70% maximum size, respectively. Quantification of growth is possible in Janenschia using polish lines: the specimen studied reached sexual maturity at ≥11 years, attained maximum size at ≥26 years, and died at ≥38 years.

Download Full-text

ISOTOPE SCLEROCHRONOLOGY AND SEASON OF ANNUAL GROWTH LINE FORMATION IN LIMPET SHELLS (PATELLA VULGATA) FROM WARM- AND COLD-TEMPERATE ZONES IN THE EASTERN NORTH ATLANTIC

Palaios ◽

10.2110/palo.2012.p12-038r ◽

2013 ◽

Vol 28 (6) ◽

pp. 386-393 ◽

Cited By ~ 21

Author(s):

D. SURGE ◽

T. WANG ◽

I. GUTIERREZ-ZUGASTI ◽

P. H. KELLEY

Keyword(s):

North Atlantic ◽

Annual Growth ◽

Growth Line ◽

Line Formation ◽

Patella Vulgata ◽

Eastern North Atlantic

Download Full-text

An analysis of the growth bands and ridges of barnacle shell plates

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400016052 ◽

1975 ◽

Vol 55 (2) ◽

pp. 439-461 ◽

Cited By ~ 38

Author(s):

Edwin Bourget ◽

Dennis J. Crisp

Keyword(s):

Outer Surface ◽

Periodic Structures ◽

Thin Layers ◽

Growth Line ◽

Shell Material ◽

Shell Wall ◽

Dark Line ◽

Thin Sections ◽

Growth Bands ◽

Discontinuous Growth

Periodic structures indicating discontinuous growth of shell wall plates have been observed in thin sections of shell and on the outer surface of shell plates of many species of operculate (Bourget, 1975). When sectioned and etched the shell plates appear to be composed of successive thin layers of shell material, each layer consisting of a few rows of fine crystals. Where two layers are adjoined, a dark line, marking the junction of two incremental zones, is clearly visible. The thin layers of shell have been termed growth bands whereas the junction of adjoining layers will be referred to as the growth line.

Download Full-text

Alternative models for allozyme-associated heterosis in the marine bivalve Spisula ovalis.

Genetics ◽

10.1093/genetics/139.4.1719 ◽

1995 ◽

Vol 139 (4) ◽

pp. 1719-1726 ◽

Cited By ~ 5

Author(s):

P David ◽

B Delay ◽

P Berthou ◽

P Jarne

Keyword(s):

Genetic Basis ◽

Linear Models ◽

Growth Parameters ◽

Shell Growth ◽

Maximum Size ◽

Age And Growth ◽

Individual Growth ◽

Marine Bivalve ◽

Initial Growth ◽

Genomic Effects

Abstract Correlations between allozyme heterozygosity and fitness-related traits, especially growth, have been documented in natural populations of marine bivalves. However, no consistent pattern has been exhibited, because heterotic effects on size vary with age and individual growth parameters are generally unknown. No consensus has emerged on the genetic basis of allozyme-associated heterosis. The species studied here, Spisula ovalis, displays annual shell growth lines, which allows us to compute individual age and growth dynamics over the whole life span. Our morphological study was coupled to a protein electrophoresis study at seven polymorphic loci. While the maximum size gained is not related to heterozygosity, the age at half maximum size, t1/2, is significantly negatively correlated with heterozygosity, indicating an heterotic effect on initial growth. The correlation between heterozygosity and size is expected to vanish when age increases, due to the form of the growth function. This decreasing correlation is consistent with previous studies. We compare the relative performances of five linear models to analyze the genetic basis of heterosis. Surprisingly, the largest part of variance in t1/2 is due to additive effects, the overdominant components being much weaker. Heterosis is therefore due to general genomic effects rather than to local overdominance restricted to allozymes or small neighboring chromosomal segments. A significant dependence of individual heterotic contributions of the enzyme loci upon expected heterozygosities, rather than metabolic function, further supports the hypothesis of enzymes acting as markers. General genomic effects can hold only if allozyme heterozygosity is positively correlated with heterozygosity at fitness-related genes scattered throughout the genome. This hypothesis is supported here by heterozygosity correlations between enzymatic loci.

Download Full-text

Annual cycle of shell growth increment formation in two continental shelf bivalves and its paleoecologic significance

Paleobiology ◽

10.1017/s0094837300006837 ◽

1980 ◽

Vol 6 (3) ◽

pp. 331-340 ◽

Cited By ~ 118

Author(s):

Douglas S. Jones

Keyword(s):

Growth Rate ◽

Continental Shelf ◽

Annual Cycle ◽

Shell Growth ◽

Growth Increment ◽

Age And Growth ◽

Growth Line ◽

Arctica Islandica ◽

Growth Increments ◽

Increment Formation

The bivalvesSpisula solidissima, the Atlantic surf clam, andArctica islandica, the ocean quahog, from the continental shelf off New Jersey, contain repeating structures in their shells. By analyzing the growing shell margins in living specimens at bi-weekly (or sometimes monthly) intervals throughout two consecutive years, it was possible to define an annual cycle of shell growth increment formation in both species. The shell increments in each species are microstructurally distinct units that form over a period of several months at select seasons of the year. Each species has two alternating shell growth increments, GI I and GI II. GI I (the annual growth line of previous studies) is formed annually in the late summer-fall inS. solidissimaand in the fall-early winter inA. islandica.These periods correspond to the spawning phase of the reproductive cycle in both species. No winter rings were found. The annual increments were used to determine age and growth rate in both Recent and Pleistocene specimens. They may also be useful in determining season of death. Because shell growth increments are formed in synchrony among living populations in these species, mass mortalities may be distinguished in the fossil record. Accurate age and growth rate determinations in fossils are important in many paleobiologic contexts, such as deciding between increased longevity or growth rate in cases of phyletic size increase.

Download Full-text

Anaerobiosis and a Theory of Growth Line Formation

Science ◽

10.1126/science.198.4323.1222 ◽

1977 ◽

Vol 198 (4323) ◽

pp. 1222-1227 ◽

Cited By ~ 104

Author(s):

R. A. Lutz ◽

D. C. Rhoads

Keyword(s):

Growth Line ◽

Line Formation

Download Full-text

Evidence for stage-based larval vulnerability and resilience to acidification in Crassostrea virginica

Journal of Molluscan Studies ◽

10.1093/mollus/eyaa022 ◽

2020 ◽

Vol 86 (4) ◽

pp. 342-351

Author(s):

A Whitman Miller ◽

Amanda Reynolds ◽

Mark S Minton ◽

Rachel Smith

Keyword(s):

Image Analysis ◽

Crassostrea Virginica ◽

Early Stage ◽

Larval Growth ◽

Growth Line ◽

Small Range ◽

Scanning Electron Micrographs ◽

High Co2 ◽

Low Co2 ◽

Physiological Capacity

ABSTRACT Using image analysis of scanning electron micrographs (SEMs), we compared differences in growth of D-stage veligers [i.e. prodissoconch I and II (PI and PII) larvae] of eastern oysters Crassostrea virginica grown in mesohaline water under high- and low-CO2 conditions. We found SEMs to reveal no evidence of dissolution or shell structure deformity for larval shells in either of the CO2 treatments but detected prominent growth lines in the PII regions of larval shells. The number of growth lines closely approximated the duration of the experiment, suggesting that growth lines are generated daily. Mean growth line interval widths were 20% greater for larval shells cultured in low- vs high-CO2 conditions. Crassostrea virginica veliger larvae were shown to tolerate high CO2 levels and aragonite saturation states (Ωarag) < 1.0, but larval growth was slowed substantially under these conditions. Differences in growth line interval width translate into substantial changes in shell area and account for previously observed differences in total shell area between the treatments, as determined by light microscopy and image analysis. Other studies have documented high mortality and malformation of D-stage larvae in bivalves when pre-veliger life stages (i.e. eggs, gastrula and trochophores) were exposed to elevated CO2. Our experiments revealed statistical differences in rates of larval survival, settlement and subsequent early-stage spat mortality for veligers reared in high- and low-CO2 conditions. Although each of these rates was measurably affected by high CO2, the magnitude of these differences was small (range across categories = 0.7–6.3%) suggesting that the impacts may not be catastrophic, as implied by several previous studies. We believe the apparent disparity among experimental results may be best explained by differential vulnerability of pre-veliger stage larvae and veligers, whereby PI and PII larvae have greater physiological capacity to withstand environmental conditions that may be thermodynamically unfavourable to calcification (i.e. Ωarag < 1.0).

Download Full-text

Identification of methionine -rich insoluble proteins in the shell of the pearl oyster, Pinctada fucata

Scientific Reports ◽

10.1038/s41598-020-75444-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hiroyuki Kintsu ◽

Ryo Nishimura ◽

Lumi Negishi ◽

Isao Kuriyama ◽

Yasushi Tsuchihashi ◽

...

Keyword(s):

Calcium Carbonate ◽

Pearl Oyster ◽

Pinctada Fucata ◽

Nacreous Layer ◽

Solid Complex ◽

Prismatic Layer ◽

Initial Stage ◽

Organic Matrices ◽

Aggregation Activity ◽

Main Components

Abstract The molluscan shell is a biomineral that comprises calcium carbonate and organic matrices controlling the crystal growth of calcium carbonate. The main components of organic matrices are insoluble chitin and proteins. Various kinds of proteins have been identified by solubilizing them with reagents, such as acid or detergent. However, insoluble proteins remained due to the formation of a solid complex with chitin. Herein, we identified these proteins from the nacreous layer, prismatic layer, and hinge ligament of Pinctada fucata using mercaptoethanol and trypsin. Most identified proteins contained a methionine-rich region in common. We focused on one of these proteins, NU-5, to examine the function in shell formation. Gene expression analysis of NU-5 showed that NU-5 was highly expressed in the mantle, and a knockdown of NU-5 prevented the formation of aragonite tablets in the nacre, which suggested that NU-5 was required for nacre formation. Dynamic light scattering and circular dichroism revealed that recombinant NU-5 had aggregation activity and changed its secondary structure in the presence of calcium ions. These findings suggest that insoluble proteins containing methionine-rich regions may be important for scaffold formation, which is an initial stage of biomineral formation.

Download Full-text