The brachiopod Argyrotheca cuneata (Brachiopoda: Megathyrididae) is reported for the first time from the southern coast of Türkiye. Twenty-three complete specimens were found in samples of shell grit taken from depths less than 5 m. The findings suggest that A. cuneata may be a common brachiopod species in shallow nearshore habitats along the southern coasts of the country. Widths of the largest and the smallest specimens were 3.7 mm and 0.71 mm, respectively. A comparison of shell dimensions of all specimens indicate an allometric change in the shape of A. cuneata during growth from being longer than wide to wider than long. The protegula preserved on the smallest specimens are described and illustrated possibly for the first time for this species.

This study analysed and compared the shell shape, morphometrics and relative growth of four sympatric limpet species (Patella depressa, Patella ulyssiponensis, Patella vulgata and Siphonaria pectinata) collected at Praia da Luz in Lagos (Algarve coast – southern Portugal). Morphometric relationships were established through regression analysis between linear (shell length, width and height), ponderal (total weight), area (shell base and surface areas) and volume variables (shell internal and total volumes). Relative growth (isometry vs allometry) was analysed to assess variation in the growth rate of morphometric variables throughout the species ontogeny. In addition, morphometric indices (ellipticity, conicity, density, surface area and volumetry) were calculated to further characterize shell shape. Overall, 1482 individuals with broad size and weight ranges were analysed (P. depressa = 354; P. ulyssiponensis = 306; P. vulgata = 408; S. pectinata = 414). All regressions were highly significant (P < 0.001) and the morphometric variables were strongly correlated (r = 0.761 to 0.994). Among 28 morphometric relationships, there were 14 isometries, 13 positive allometries and only one negative allometry. The morphometric indices revealed clear morphological differences between species and were mostly size-dependent, reflecting gradual changes in shell shape during growth. The main results are compared with a compilation of analogous data reported for these limpet species throughout their distributional range. Overall, the general trends in relative growth are discussed in terms of the species life habits, main traits and functional morphology.

Archaic projectile points from the Andean Altiplano exhibit a curious trend of increasing size over time, in contrast to a well-documented size reduction throughout North America. Although a number of hypotheses exist to account for decreasing projectile-point size, there are currently no explicit explanations for increasing size. We consider several hypotheses and interrogate two techno-economic hypotheses. We posit that increasing point size compensated for lost dart momentum or accuracy that resulted from the shortening of atlatls or atlatl darts as wood became increasingly scarce on the tree-sparse Altiplano. We evaluate these hypotheses using a replicated Andean atlatl system in ballistic trials. Contrary to expectation, results show that point enlargement significantly reduces penetration depth, allowing us to confidently reject the momentum hypothesis. Point enlargement, in contrast, tentatively correlates positively with accuracy. Our experiment further shows that camelid bone is an effective and economical alternative to wood for atlatl production. Despite suboptimal lengths, camelid radioulna atlatls have a convenient morphology that requires low production time, which helps explain empirically observed camelid bone atlatls from the Andean highlands. More generally, our observations lead us to consider that central tendencies in archaeologically observed projectile-point size may reflect a trade-off between penetration and accuracy.

Projectile points are a common subject of archaeological study. In the past decade, landmark-based geometric morphometrics (LGM) has increasingly been used to analyze points as whole objects. LGM and other studies document allometric changes in points—change in shape with change in size—as a product of resharpening. Allometry registers in part because different segments or modules of points are subject to different degrees of resharpening, with blades often experiencing more reduction than stems. Different modules retain varying degrees of morphological integrity as points move through their use lives. Most previous LGM studies involved two-dimensional point models, and few tested directly for modularity. We apply LGM methods to three-dimensional models of Folsom point replicas whose degree and pattern of reduction are known, finding evidence for both allometry and modularity, with modest integration. Complementary non-LGM data reveal similar results, indicating a robust pattern and ways to approximate LGM results in other data. Moreover, our dataset's experimental control clearly identifies the results as a function of the progressive reduction in use experienced by points.

Mineral composition and relative deposition rates in the pig’s body are used to assess the mineral net requirements for growth and input–output balances. The study aimed to examine the dynamics of changes in mineral composition and deposition rates in the empty body (EB) from birth to 140 kg BW depending on dietary protein supply. In the experiment, 66 entire male, 58 castrated and 66 female Swiss Large White pigs were used to determine body composition at birth, 10, 20 kg and at 20 kg intervals from 40 to 140 kg BW. From 20 kg BW, they had either ad libitum access to a control grower and finisher diet or a grower and finisher diet containing 80% CP, lysine, methione+cystine, threonine and tryptophan of the control diet. Each EB fraction (carcass, organs and empty intestines, blood and bile) was weighed and analyzed for water, ash, calcium, phosphorous, magnesium, potassium, sodium, copper, iron, manganese and zinc contents. Allometric relationships between the amount of each mineral in the EB and the EB weight (EBW) were fitted. The R2 of the allometric equations was above 0.92, except for copper and manganese (below 0.33), revealing the EBW as an excellent explanatory variable of the analyzed amounts. The copper and manganese composition in the EB were extremely low and variable which explain the low R2. Except for zinc, all mineral relative deposition rates decreased with increasing EBW. The amount of ash, calcium and phosphorus in the EB was not affected by the diet, but when expressed relative to body protein these minerals were increased when pigs were fed the low protein diet. This suggests an independent protein deposition and bone mineralization when animals are fed diets limiting in protein content. The diet also affected the amount of potassium in the EB which was greater when the low protein diet was fed. The gender only affected the amounts of potassium and sodium in the EB which were greater in entire males. Entire males had also greater amounts of water in the EB, which may explain the observed effect of gender on these two electrolytes. Finally, gender and dietary protein did not affect to a sufficient relevant way the body mineral composition and deposition rates in the EB, suggesting that their distinction may not be necessary to assess, on BW basis, the mineral net requirements for growth and the exported amount of minerals in input–output balances.

Tropical bamboos persist in a wide range of light conditions and quickly respond to changes in light availability. However, the mechanisms underpinning this ability remain unknown. In order to test the hypothesis that the modular and hollow culm architecture of bamboos explains their performance in a wide range of light environments, we determined the allometric relationships of two dominant bamboo species of the upper hill dipterocarp forests of Malaysia, Gigantochloa ligulata (n = 29) and Schizostachyum grande (n = 25), via destructive sampling. We also monitored biomass turnover of bamboos and woody trees in 24 permanent plots (1.92 ha in total) over a one-year period. Compared with woody trees, bamboo culms attained 1.5 times the height and their clumps supported four times as much total leaf area at the same above-ground biomass. In addition, at a given height, bamboo clumps had six times larger crown projection area than trees while having a similar amount of total leaf area per unit of crown projection area. Finally, bamboos’ biomass turnover rate was three times higher than trees, and G. ligulata increased its specific rate of biomass increase after canopy disturbance, while trees decreased. We conclude that the unique architecture of bamboos allows them to persist under closed forest canopy light conditions and to respond to gap formation via high biomass turnover rate.

Multiple introductions of an exotic species can facilitate invasion success by allowing for a wider range of expressed trait values in the adventive range. Schinus terebinthifolius (Brazilian peppertree) is an invasive shrub that was introduced into Florida in two separate introductions and has subsequently hybridized, resulting in three distinct lineages (eastern, western, and hybrid). To determine whether allocation of aboveground biomass differed by introduction history, we destructively sampled 257 stems from each of six populations with differing introduction histories. The proportion of aboveground biomass allocated to fruit, wood, and leaves differed among the three populations. To determine whether the relationship between stem size and several dependent variables that measure plant performance (total dry weight, wood dry weight, number of fruits, fruit dry weight, leaf dry weight, and number of leaves) differed quantitatively by introduction history, we performed analyses of covariance. Slopes of these relationships (dependent variable vs. stem size) varied by lineage. Hybrid populations had the steepest slopes for one set of dependent variables (total dry weight, wood dry weight, and leaf dry weight), while western populations had the steepest slopes for a different set of dependent variables (number of fruits, fruit dry weight, and number of leaves). The parameterized regression equations for each dependent variable and lineage were used to nondestructively estimate different kinds of production by individuals that are part of long-term longitudinal studies to understand the demographic consequences of these different biomass allocation strategies for the performance of S. terebinthifolius individuals across the invaded range in Florida.

Characterizing the response of weeds to canopy shade is important for improved understanding of crop–weed competition and weed population dynamics. In 2000 and 2001, field studies were conducted in central New York state to examine the influence of three neighbor types (none, broccoli, or broccoli plus winter rye) and two locations (between or within rows of broccoli) on the morphology, phenology, and seed germination characteristics of Powell amaranth. Reductions in light availability and in the ratio of red-to-far red light were associated with increases in (1) partitioning of dry weight to stem tissue, (2) stem elongation, and (3) specific leaf area. Canopy shade also resulted in fewer main leaves at flowering and a reduced rate of leaf appearance but had no effect on the number of days to flowering. The relationship between Powell amaranth fecundity and aboveground dry weight was allometric, with both parameters declining significantly under competition. The weight of seeds produced did not vary significantly according to the competitive environment experienced by the maternal parent. However, the germination percentage of viable seeds was 40 to 50% lower for seeds maturing on plants grown under competition than without competition. Reductions in the number of main leaves at flowering and increased seed dormancy may be adaptive responses to canopy shade. Both mechanistic crop–weed competition models and population dynamic models would benefit from incorporation of data on the phenotypic plasticity of morphology, phenology, and seed germination characteristics of weeds.

The present study investigated the population dynamics of Exhippolysmata oplophoroides in an area influenced by upwelling, focusing on reproductive period, sex ratio, growth rate, longevity, mortality, relative growth and size of sex change. We also tested the hypothesis that the appendices internae increased in size with sex change from the male to the simultaneous hermaphrodite phase as possible replacements for the male appendices masculinae, which are reduced or lost at sex change. Population structure was assessed by the distribution of size frequency in three demographic groups: male phase, hermaphrodite phase with, and without embryos. For relative growth analysis, the length of the following structures was measured: carapace, second pleuron, first pereopod, second pereopod, appendices internae of the second to fifth pleopods, and appendix masculina. Smaller size classes were composed only by male-phase individuals. The sex ratio was significantly biased towards the simultaneous hermaphrodite phase. Reproduction was continuous in the population throughout the year. Slower growth rates but higher maximum body sizes than those estimated at other locations in south-eastern Brazil were observed in the population studied. Cooler temperatures and higher nutrient levels associated with upwelling may have produced this pattern of reproduction and growth, similar to that found in more southerly austral latitudes. We also found that sex change influences the relative growth of body structures such as the second pereopods, appendices internae, and appendix masculina, and hypotheses on the adaptive value of such allometric growth are proposed.

This study reports the morphometric relationships and relative growth of 20 uncommon bivalve species collected along the Algarve coast (southern Portugal). Morphometric relationships were established between three linear variables (shell length, height and width) and one ponderal variable (total weight) and the relative growth between variables (isometry vs allometry) was analysed in order to assess their variation throughout ontogeny. In addition, morphometric indices (elongation, compactness, convexity and density) based on ratios of those linear and ponderal variables were calculated in order to further characterize morphologically the bivalve species. A total of 2512 individuals belonging to nine bivalve families were analysed, comprising specimens with broad ranges in both shell length (11.8–109.0 mm SL) and total weight (0.2–354.6 g TW). All morphometric relationships were highly significant (P < 0.001) and displayed invariably high correlation coefficients (r = 0.727–0.998). Among a total of 60 morphometric relationships, 27 isometries, 25 positive allometries and 8 negative allometries were registered. The morphometric indices displayed a remarkable variation among taxa, reflecting the high morphological diversity of these miscellaneous bivalve species. Discriminant analysis provided a spatial visualization of the species morphometric variables that further evidenced their main shape features, the distinctness between some species and families (e.g. Pharidae and Cardiidae) and the morphological resemblance among some species belonging to other families (e.g. Veneridae and Tellinidae). Overall, this information is useful and has practical application in diverse research fields, including studies on systematics and taxonomy, physiology, biology, ecology, fisheries assessment and management.

We studied the relationship between flower size and nectar properties of hummingbird-visited flowers in the Brazilian Atlantic Forest. We analysed the nectar volume and concentration as a function of corolla length and the average bill size of visitors for 150 plant species, using the phylogenetic generalized least squares (PGLS) to control for phylogenetic signals in the data. We found that nectar volume is positively correlated with corolla length due to phylogenetic allometry. We also demonstrated that larger flowers provide better rewards for long-billed hummingbirds. Regardless of the causal mechanisms, our results support the hypothesis that morphological floral traits that drive partitioning among hummingbirds correspond to the quantity of resources produced by the flowers in the Atlantic Forest. We demonstrate that the relationship between nectar properties and flower size is affected by phylogenetic constraints and thus future studies assessing the interaction between floral traits need to control for phylogenetic signals in the data.

Sexual maturity of the spider crab Libinia ferreirae was assessed for each sex, based on body dimensions and observations of gonad condition. A total of 346 crabs were analysed, of which 68% were females. Immature and adult individuals were recognized based on their allometric growth and gonad development. Abdomen width (AW) vs carapace width (CW) and propodus length (PL) vs CW were the relationships that best separated allometric groups of females and males, respectively. For females, gonad and allometric morphological maturity were, respectively, 38.77 and 39.43 mm of CW, which is close to the carapace size of the smallest ovigerous female (38.08 mm). For males, gonad maturity was 34.86 mm of CW and three allometric phases were observed: immature (IM♂), adolescent (AD♂) and adult morphometrically mature (MM♂). The IM♂ phase showed lower values of CW and PL than the AD♂ phase, without spermatophores inside the vas deferens; the AD♂ phase exhibited higher CW values than IM♂, but lower CW and PL values than the MM♂ phase, and the presence of spermatophores in the vas deferens; the MM♂ phase had higher values of CW and PL than the AD♂ phase and spermatophores in the vas deferens. Therefore, females showed synchronic morphometric, gonadal and functional maturity, while in males, gonadal maturity was attained before morphometric maturity, which probably could be a reproductive strategy for this species.

The bivalve ligament provides the thrust for shell opening, acting as the resistance in a lever system against which adductor muscle effort is applied. Usually, its outer lamellar layer is subjected to tensile stress, while the inner fibrous layer is compressed, with the pivotal axis located between them. However, opisthogyrate rostrate bivalves display a concave dorsal margin, and both the umbo and the postero-dorsal angle of the shell project dorsally to the ligament, which then fails to act as pivotal axis. Three opisthogyrate rostrate genera of unrelated lineages show somewhat different solutions to this morpho-functional challenge. In Cuspidaria (Anomalodesmata), the ligament is internal, subjected only to compression and ventral to the pivotal axis, a thickened periostracum develops, forcing the dorsal margins of the valves to act as pivotal axis, and the posterior parts of the shell's dorsal margins gape dorsally. In Nuculana (Palaeotaxodonta), the inner layer of the ligament is internal, the outer layer is external but reduced, and some species develop a dorsal ridge parallel to the commissural plane, on a level with the rostrum and acting as pivotal axis. In Pterotrigonia (Palaeoheterodonta) and other rostrate trigoniides, the ligament is external opisthodetic, but is allometrically reduced. Trigoniides may also develop a dorsal ridge.

Juvenile tropical trees grow from the shaded understorey to the high-light conditions of the canopy, but actual height growth trajectories towards the canopy remain unknown. Although height growth is the determining factor for reaching the canopy, investment in diameter growth is needed to sustain mechanical stability. We quantified variation in long-term juvenile tree growth patterns in diameter and height within three Bolivian moist forest species, and evaluated whether diameter growth and height growth were related. We reconstructed lifetime growth in diameter and height for 21–27 juvenile trees per species by measuring tree rings at various heights in the stem. Growth in diameter and height strongly varied among and within tree species. The light-demanding species Cedrelinga cateniformis needed just 6–19 y to reach a height of 3 m, while the more shade-tolerant species Clarisia racemosa and Peltogyne cf. heterophylla needed 8–39 y and 13–43 y, respectively. Diameter growth and height growth were not, or just weakly, positively related, and trees of the same height displayed a wide range in stem diameter. Our results indicate that trees of all three species shifted investment in diameter growth and height growth over time, most likely in response to variation in light levels.

The objective of this study was to characterize the early development and allometric growth of the grumatã (Prochilodus vimboides). We describe a sample of 266 eggs and larvae obtained through induced spawning. The eggs were spherical (mean 3.7 mm diameter), exhibited a yellow yolk and were non-adhesive and pelagic after fertilization and hydration. The time elapsed between the early cleavage and post-flexion stages was considered short (328 hours, 8054 hour-degrees) in regard to the development times of other Neotropical rheophilic species, but time to hatching was considerably longer than in other Prochilodus species. The most notable anatomical changes were observed between the end of the yolk larval stage and the beginning of the pre-flexion stage, when the larvae displayed directed swimming and the digestive system became functional, enabling the transition from endogenous to exogenous feeding. After hatching, the larvae grew from 6.04 to 15.15 mm in total length average. Two growth phases were observed at this stage: a non-linear asymptotic curve in yolk-sac larvae, and a linear constant-rate growth phase after exogenous feeding started. Allometric growth related to standard length was positive for head length, negative for eye diameter, and switched between phases from negative to positive in body depth and head height. Morphological development and allometric growth in different larval phases impose drastic anatomical and physiological changes that are synchronic with habitat changes and the flood cycles during the reproductive period.

We examine the relationship of biomass B and length L in the eastern oyster Crassostrea virginica by focusing on the scaling exponent b in the allometric equation B = aLb using four datasets: Delaware Bay, Chesapeake Bay, Galveston Bay and a regionally extensive compilation from the NOAA Mussel Watch Program. The average value of the scaling exponent in Delaware Bay and Chesapeake Bay is about 2. For Galveston Bay, the value is distinctly higher, near 2.6. Over all Mussel Watch sites, the value is again near 2. Within Delaware Bay, the salinity gradient exerts an important effect. Shells are longer for their meat weight at lower salinities. The range of scaling exponents revealed by Mussel Watch data is exceedingly large (b < 1 to >3). Scaling exponents below 2.5 are unusual in bivalves. Among bivalves, only other oyster taxa have comparably low scaling exponents averaging near 2. We propose that oyster biomass routinely scales nearer the square of the length rather than the cube and that this is a constraint imposed by the exigency of carbonate production for reef maintenance and accretion in the face of high rates of taphonomic degradation. The adaptation as a reef builder requires the formation of carbonate that rapidly breaks down, thus requiring that carbonate produced be maximized. A biomass-to-length scaling exponent of 2 provides a mechanism to maximize shell production relative to biomass, while at the same time providing maximum surface area for the all-important settling of oyster spat to maintain the population.