Crab Claw Research Articles

Characteristics of corneal topographic and pachymetric patterns in patients with pellucid marginal corneal degeneration

To determine the characteristics of the shape of the cornea in patients with pellucid marginal corneal degeneration (PMD) and to compare these characteristics to those of eyes with keratoconus and eyes of normal subjects. This was a retrospective, cross-sectional case-series in which 49 eyes of 33 patients with PMD, 51 eyes of 51 patients with keratoconus and 53 eyes of 53 subjects with normal corneas (controls) were examined and compared. For all eyes, we obtained the topographic patterns of the axial power maps, anterior and posterior elevation maps and pachymetric maps using a rotating Scheimpflug camera. The eyes were classified into the respective patterns by visual inspection of these maps. In eyes with PMD, the most common axial power map pattern was the crab claw pattern (78 %) followed by the inferior steepening pattern (18 %). In eyes with keratoconus, the most common pattern was the inferior steepening pattern (67 %). The most common pattern in the elevation maps for both surfaces was the asymmetric island in eyes with PMD and keratoconus. Although the decentered pattern, including the decentered oval (27 %) and decentered round (20 %) pattern, on pachymetric map was specific to eyes with PMD, the incidence of these patterns was relatively low. The similarity in the topographic and pachymetric patterns in eyes with PMD and keratoconus suggests that they may be a continuity of the same disorder with different phenotypes.

Experimental study and numerical modeling of the freezing process of marine products

An increasing interest in the exploitation of new Patagonian marine crabs was manifested by the industry, due to their commercial value as frozen products. In the present work the freezing of two products: crab meat in plastic pouches and crab claws was experimentally conducted and numerically modeled. Non linear, non-stationary heat conduction partial differential equations were solved to simulate the freezing of pouches, using a computational program in finite elements coded by the authors. The freezing of crab claws was simulated considering the irregular geometry of the system and two domains with different thermal properties (crab meat in contact with a calcareous layer) using Heaviside and Gaussian functions, to obtain a smoother specific heat curve. Heat transfer coefficients in the industrial tunnel freezer were determined from independent experiments. The influence of the freezing rate on the size of the ice crystals was determined by histological observations. Numerical models were satisfactorily validated by means of experimental time–temperature curves obtained at industrial scale in freezing tunnels. Tracking of the warmest point paths in each product was performed. These simulations are of great value for food process design and can help to optimize and control the freezing of new products.

POWERDRESS and Diversified Expression of the MIR172 Gene Family Bolster the Floral Stem Cell Network

Termination of the stem cells in the floral meristem (also known as floral determinacy) is critical for the reproductive success of plants, and the molecular activities regulating floral determinacy are precisely orchestrated during the course of floral development. In Arabidopsis thaliana, regulators of floral determinacy include several transcription factor genes, such as APETALA2 (AP2), AGAMOUS (AG), SUPERMAN (SUP), and CRABSCLAW (CRC), as well as a microRNA (miRNA), miR172, which targets AP2. How the transcription factor and miRNA genes are coordinately regulated to achieve floral determinacy is unknown. A mutation in POWERDRESS (PWR), a previously uncharacterized gene encoding a SANT-domain-containing protein, was isolated in this study as an enhancer of the weakly indeterminate ag-10 allele. PWR was found to promote the transcription of CRC, MIR172a, b, and c and/or enhance Pol II occupancy at their promoters, without affecting MIR172d or e. A mutation in mature miR172d was additionally found to enhance the determinacy defects of ag-10 in an AP2-dependent manner, providing direct evidence that miR172d is functional in repressing AP2 and thereby contributes to floral determinacy. Thus, while PWR promotes floral determinacy by enhancing the expression of three of the five MIR172 members as well as CRC, MIR172d, whose expression is PWR-independent, also functions in floral stem cell termination. Taken together, these findings demonstrate how transcriptional diversification and functional redundancy of a miRNA family along with PWR-mediated co-regulation of miRNA and transcription factor genes contribute to the robustness of the floral determinacy network.

Characterization of a Crabs Claw Gene in basal eudicot species Epimedium sagittatum (Berberidaceae).

The Crabs Claw (CRC) YABBY gene is required for regulating carpel development in angiosperms and has played an important role in nectary evolution during core eudicot speciation. The function or expression of CRC-like genes has been explored in two basal eudicots, Eschscholzia californica and Aquilegia formosa. To further investigate the function of CRC orthologous genes related to evolution of carpel and nectary development in basal eudicots, a CRC ortholog, EsCRC, was isolated and characterized from Epimedium sagittatum (Sieb. and Zucc.) Maxim. A phylogenetic analysis of EsCRC and previously identified CRC-like genes placed EsCRC within the basal eudicot lineage. Gene expression results suggest that EsCRC is involved in the development of sepals and carpels, but not nectaries. Phenotypic complementation of the Arabidopsis mutant crc-1 was achieved by constitutive expression of EsCRC. In addition, over-expression of EsCRC in Arabidopsis and tobacco gave rise to abaxially curled leaves. Transgenic results together with the gene expression analysis suggest that EsCRC may maintain a conserved function in carpel development and also play a novel role related to sepal formation. Absence of EsCRC and ElCRC expression in nectaries further indicates that nectary development in non-core eudicots is unrelated to expression of CRC-like genes.

Evolutionary variation in the mechanics of fiddler crab claws

BackgroundFiddler crabs, genus Uca, are classic examples of how intense sexual selection can produce exaggerated male traits. Throughout the genus the enlarged “major” cheliped (claw) of the male fiddler crab is used both as a signal for attracting females and as a weapon for combat with other males. However, the morphology of the major claw is highly variable across the approximately 100 species within the genus. Here we address variation, scaling, and correlated evolution in the mechanics of the major claw by analyzing the morphology and mechanical properties of the claws of 21 species of fiddler crabs from the Pacific, Gulf and Atlantic coasts of the Americas.ResultsWe find that the mechanics that produce claw closing forces, the sizes of claws and the mechanical strength of the cuticle of claws are all highly variable across the genus. Most variables scale isometrically with body size across species but claw force production scales allometrically with body size. Using phylogenetically independent contrasts, we find that the force that a claw can potentially produce is positively correlated with the strength of the cuticle on the claw where forces are delivered in a fight. There is also a negative correlation between the force that a claw can potentially produce and the size of the claw corrected for the mass of the claw.ConclusionsThese relationships suggest that there has been correlated evolution between force production and armoring, and that there is a tradeoff between claw mechanics for signaling and claw mechanics for fighting.

Terrestrial arthropods from the Late Pleistocene of Jamaica: systematics, palaeoecology and taphonomy

The Red Hills Road Cave, Jamaica, is the most important site for terrestrial arthropods in the post‐Miocene of the Greater Antilles. Its fauna includes millipedes, isopods, crabs and insects, in addition to land snails and vertebrates. Arthropods are preserved in three dimensions and delicate structures such as limbs can be recognized. This unusual preservation was favoured by acidic groundwater rich in dissolved calcium carbonate; periods of high rainfall during which the bottle‐shaped cave was filled with water; and any arthropod washed in would have drowned. The absence of spiders, centipedes and most insects is due to the absence of carbonate in their exoskeletons. Millipedes and isopods possess a potential for preservation by carbonate mineralization that does not occur in other groups; they secrete calcium carbonate in the exoskeleton which hardens the cuticle and is water permeable, bringing about mineral replacement of the original structures.Within the cave, fossil millipede taxa include Rhinocricus sp. or spp., Chondrotropis sp., Caraibodesmus verrucosus (Pocock) and Cyclodesmus sp. cf. C. porcellanus Pocock. The isopod fauna includes Pseudarmadillo sp., Venezillo boonae Van Name, and Philoscia spp. 1 and 2. Crab claws belong to Sesarma sp. cf. S. cookei Hartnoll. Millipedes and isopods are particularly complete, representing drowned individuals fossilized soon after death; land crabs occur as fingers and rare chelae, suggesting that they may be exuviae. Only the most robust parts of insects have been discovered, but are particularly rare, consisting of three taxa of fly puparia and one possible beetle elytra. Copyright © 2012 John Wiley & Sons, Ltd.

Optimization Design for Crank Arc Guide Bar Gathering Mechanism of Crab Claw Type Loading Machine

This paper conducts a comprehensive study on the optimization design for crank arc guide bar gathering mechanism of crab claw type loading machine. The optimization aim is to make reality locus of gathering claw end-point be as in-accordance as possible with ideal locus, and so on. Formulae are derived for displacement of gathering claw end-point and position angle of the gathering claw. An optimization design model is established for the crank arc guide bar gathering mechanism. The crank arc guide bar gathering mechanism is optimized of crab claw type loading machine with 2100 mm wide, and the optimization result is satisfactory. Compared to the optimized crank straight line guide bar gathering mechanism in literature [2], the locus error function of gathering claw end-point has been largely improved with a reduction of 25.8%.

The class II HD-ZIP JAIBA gene is involved in meristematic activity and important for gynoecium and fruit development in Arabidopsis

Development and patterning of the gynoecium – and later the fruit – must be finely regulated to ensure the survival of the species that produces them. The process that leads to successful fruit formation starts at early stages of floral meristem development and follows a series of chronologically successive events. In a recent work we reported the functional characterization of the class II HD-ZIP JAIBA (JAB) gene. Mutant jab plants showed sporophytic defects in male and female reproductive development, and combined with the mutant crabs claw (crc) caused defects in the floral meristem (FM) determination process and gynoecium medial tissue development. Furthermore, the JAB protein interacted with transcription factors known to regulate meristematic activity, fruit development and FM determinacy. Preliminary results presented here suggest a genetic interaction between JAB and the gene SHOOT MERISTEMLESS (STM).

Pathological and physiological effects of nicking on brown crab (Cancer pagurus) in the Irish crustacean fishery

Nicking is used in fisheries to immobilize claws of brown crab (Cancer pagurus) in order to prevent cannibalism and fighting during storage. Nicking fractures the apodemes creating an open wound and damage to the internal claw tissues, which is the most valuable product of brown crab. In turn, this results in a reduction of quality of product and possibly compromises the host’s defence mechanisms to other physiological challenges experienced throughout the post-harvest process. This study assessed the effects of nicking on the physiology and pathology of brown crab from the Irish fishery over 7 days. Results showed significantly elevated levels of muscle necrosis (P=0.005), total pathologies (P=0.022) and encirculating granulocytes in nicked crab compared to non-nicked crab. Mean glucose (212.0μg/mL±108.4), lactate (36.52μg/mL±38.74) and RI (11.05n±1.78) levels were higher in nicked crab indicating increased stress levels. Overall, histology results showed a significantly higher (P=0.022) occurrence of pathologies, such as melanised nodules, in nicked animals. In addition to an observed reduction in the quality of claw muscle, nicked crab also showed significantly higher (P=0.005) levels of necrosis in claw muscle. From the results of this study it is recommended that alternative retention methods are used.

JAIBA, a class‐II HD‐ZIP transcription factor involved in the regulation of meristematic activity, and important for correct gynoecium and fruit development in Arabidopsis

The gynoecium is one of the most complex organs of a plant. After fertilization, it becomes a fruit, which has two important functions: to protect the seeds while they develop and to disperse them at maturity. The development and patterning of the gynoecium and later fruit must be finely regulated to ensure the survival of the species that produces them. The process that leads to successful fruit formation starts at early stages of floral meristem development and follows a series of chronologically successive events. In this work we report the functional characterization of the class-II homeodomain leucine zipper (HD-ZIP) JAIBA (JAB) gene. Mutant jab plants show sporophytic defects in male and female reproductive development, and combined with crabs claw cause defects in the floral meristem (FM) determination process and gynoecium medial tissue development. This suggests that proper FM determination is required for gynoecium medial tissue development, and indicates that JAB and CRC are necessary for both processes. Furthermore, the JAB protein interacts with transcription factors known to regulate meristematic activity, fruit development, and floral meristem determinacy. The sporophytic effect on pollen and embryo sac development might be an independent and later function of JAB. In summary, we present data that indicates that the JAB gene regulates meristematic activity in different tissues, and that it is necessary for the correct formation of the gynoecium at different stages, contributing to a crucial process in plant life: proper fruit development.

Above (review)

Reviewed by: Above Kate Quealy-Gainer Bobet, Leah . Above. Levine/Scholastic, 2012. [368p]. Trade ed. ISBN 978-0-545-29670-0 $17.99 E-book ed. ISBN 978-0-545-39220-4 $17.99 Reviewed from galleys R Gr. 8-12. The underground city of Safe offers sanctuary to the Sick, the Freaks, and other rejects from the world Above. Matthew was the first of a generation to be born there and has been raised by Atticus, a Freak with crab claws for hands, who is one of the founders of Safe. As the appointed Teller, Matthew is responsible for the histories of the city and its residents, but the tale takes a terrible turn when Corner, the one and only exile from Safe, returns with an army of venomous shadows, killing Atticus and scattering the other Freaks through the underground tunnels and up Above. There, Matthew and his friend Ari, a broken and troubled shape-shifter, uncover the true origins of Safe, and Matthew's role shifts from historian to judge and executioner as he rights past wrongs and attempts to build a new Safe. Richly nuanced, this complicated tale touches on notions of security, truth, and autonomy with just a hint of romantic love. Matthew's narration oscillates between a folksy, slang-ridden casualness and a poetic stream of consciousness, abundant in imagery and metaphor; the combination is disconcerting at times but also furthers the story's ethereal, illusory quality. Each of the characters is painfully, endearingly flawed, some of them irredeemably so; Corner's story of rejection, acceptance, and then rejection again is particularly compelling, and the author deftly blurs the line between villainy [End Page 447] and vulnerability without excusing Corner's horrific acts. A disjointed timeline and differing perspectives are neatly handled through Matthew's role as Teller, and his stories speak to the idea that history is shaped by what it omits as well as what it includes. The ultimate price for the return to Safe is a high one, and readers will be left wondering not only what asylum is worth but also who deserves it. Copyright © 2012 The Board of Trustees of the University of Illinois

Contribution of Sarcoplasmic Proteins to Myofibrillar Proteins Gelation

Surimi, a refined protein extract, is produced by solubilizing myofibrillar proteins during the comminuting and salting stages of manufacturing. The resulting paste gels on heating to produce kamaboko or a range of analog shellfish such as crab claw, filament sticks, fish mushroom, and so on. The myosin molecule is the major myofibrillar protein in gelation. It is believed that washing steps during the traditional surimi process play an important role in enhancing the gel properties of the resultant kamaboko by removing water-soluble (sarcoplasmic, Sp-P) proteins. By contrast, some researchers claim that retaining Sp-P or adding it into the surimi gel network not only does not interfere with the action of myofibrillar proteins during the sol-gel transition step but also improves the gel characteristics of the resultant kamaboko. It seems that retention of Sp-P or their addition into raw surimi does enhance the textural properties of kamaboko gel perhaps by functioning as a proteinase inhibitor, particularly against trypsin and trypsin-like proteinases but this depends on the type of applied surimi process. Among different types of Sp-P, it has been claimed that some proteins such as endogenous transglutaminase (TGase) play a more important role than other Sp-P in bond formation, by catalyzing the cross-linking of myosin heavy chain (MHC) molecules during low-temperature setting of surimi, resulting a more elastic kamaboko gel.

Molecular re-confirmation and floral characteristics of drooping leaf (DL) mutants generated by insertional mutagenesis in rice

Transposon tagging and insertional mutagenesis provide one of the most powerful tools in gene function studies. Here, we report a comparison between two novel drooping leaf (DL) mutants from transposon and T-DNA insertion lines of rice. DL is distinct from well-known ABC genes and a member of the YABBY gene family, and it is closely related to the CRABS CLAW (CRC) gene of Arabidopsis thaliana. Based on phenotypic analysis, DL regulated midrib formation by promoting cell proliferation in the central region of rice leaf and was necessary for the specification of carpel identity. We identified two DL mutants by screening the Ac/Ds and T-DNA insertional mutant pool of rice. Flanking sequence tag analysis indicated that both Ds and T-DNA segments were inserted in the promoter region at 3.4 kbs and 5.4 kb upstream, respectively, of the previously known OsYABBY domain. Interestingly, the progenies of DL lines of two different pools showed various degrees of leaf drooping and abnormal carpel formation. Flower structures revealed that there were more than two stigmas with normal stamens and pistils per panicle in the Ds-induced mutants. However, T-DNA induced mutant had extra stamens with staminoid carpels. These results indicate that the promoter region of DL plays an important function in regulating anther and carpel formation.

Identification of proteins interacting with lactate dehydrogenase in claw muscle of the porcelain crab Petrolisthes cinctipes

Biochemical adaptation of enzymes involves conservation of activity, stability and affinity across a wide range of intracellular and environmental conditions. Enzyme adaptation by alteration of primary structure is well known, but the roles of protein–protein interactions in enzyme adaptation are less well understood. Interspecific differences in thermal stability of lactate dehydrogenase (LDH) in porcelain crabs (genus Petrolisthes) are related to intrinsic differences among LDH molecules and by interactions with other stabilizing proteins. Here, we identified proteins that interact with LDH in porcelain crab claw muscle tissue using co-immunoprecipitation, and showed LDH exists in high molecular weight complexes using size exclusion chromatography and Western blot analyses. Co-immunoprecipitated proteins were separated using 2D SDS PAGE and analyzed by LC/ESI using peptide MS/MS. Peptide MS/MS ions were compared to an EST database for Petrolisthes cinctipes to identify proteins. Identified proteins included cytoskeletal elements, glycolytic enzymes, a phosphagen kinase, and the respiratory protein hemocyanin. Our results support the hypothesis that LDH interacts with glycolytic enzymes in a metabolon structured by cytoskeletal elements that may also include the enzyme for transfer of the adenylate charge in glycolytically produced ATP. Those interactions may play specific roles in biochemical adaptation of glycolytic enzymes.

Empowering plant evo‐devo: Virus induced gene silencing validates new and emerging model systems

DOI: 10.1002/bies.201100040 In the above article, I –the author- review and discuss recent applications of virus induced gene silencing (VIGS) to the field of evolution of development (evo-devo). For greater completeness of relevant references, I would like to acknowledge additional research in this area, which I unfortunately missed at the time I wrote the article. An article by Yellina et al. (2010) investigates the function of two C class AGAMOUS homologs in Eschscholzia californica (California poppy). Lee et al. (2005) use VIGS to investigate the role of the YABBY gene CRABSCLAW in nectary development in several core eudicots compared to a basal eudicot. These two articles constitute additional examples of VIGS successfully applied to evo-devo questions and should therefore have been included in Table 1. Lee, J.Y., Baum, S.F., Oh, S.H., Jiang, C.Z., Chen, J.C., and Bowman, J.L. (2005). Recruitment of CRABS CLAW to promote nectary development within the eudicot clade. Development 132, 5021–5032. Yellina, A.L., Orashakova, S., Lange, S., Erdmann, R., Leebens-Mack, J., and Becker, A. (2010). Floral homeotic C function genes repress specific B function genes in the carpel whorl of the basal eudicot California poppy (Eschscholzia californica). EvoDevo 1, 13.

Thermoregulation as an Alternate Function of the Sexually Dimorphic Fiddler Crab Claw

Fiddler crabs are highly sexually dimorphic. Males possess one small (minor) feeding claw and one greatly enlarged (major) claw; females possess two small claws. The major claw is used to attract mates and for burrow defense, but it is costly for the male to possess. We tested the hypothesis that the major claw also functions as a thermoregulatory structure, a function that would allow males to spend a greater amount of time at the surface, foraging and attracting potential mates. Fiddler crabs Uca panacea were exposed to a source of radiant heat and body temperatures were monitored. Four groups of crabs were tested: intact males, males with the minor claw removed, males with the major claw removed, and females. The body temperatures of males without the major claw increased more rapidly and reached higher values than did those of males with the major claw intact, but the results from these animals were similar to those of females. These results support the hypothesized thermoregulatory function of the major claw. The major claw may function as a heat sink, transferring heat away from the body and dissipating it into the air. Enhanced thermoregulatory ability provided by the major claw may partially ameliorate the energetic costs of possessing such a large claw.

Evolution of the YABBY gene family with emphasis on the basal eudicot Eschscholzia californica (Papaveraceae)

YABBY genes are seed plant-specific transcriptional regulators that are involved in diverse aspects of leaf, shoot and flower development. A series of duplications gave rise to five gene groups found throughout flowering plants. In Arabidopsis and other species, expression of two gene groups, CRABS CLAW and INNER NO OUTER, is restricted to floral organs. In contrast, members of the FILAMENTOUS FLOWER, YABBY2 and YABBY5 gene groups are also expressed in leaves and have been termed 'vegetative YABBYs'. How the five paralogue groups evolved and how their expression and function diversified have remained largely unresolved, precluding a reconstruction of the natural history of this gene family. Here, we report new genes from Eschscholzia californica (Ranunculales, Papaveraceae) that we use together with currently available database sequences in a comprehensive phylogenetic re-evaluation of the YABBY gene family. Multilayered Bayesian analysis covering seed plants allowed us to locate Eschscholzia YABBY sequences within the gene family phylogeny. We established that vegetative YABBYs do not form a monophyletic clade, and that CRABS CLAW and FILAMENTOUS FLOWER arose from a common ancestor gene. INNER NO OUTER genes are sister to that ancestral gene. We identified several conserved motifs outside of known amino acid domains that define all five angiosperm YABBY gene clades. Further, we inferred the evolution of gene expression and provide evidence for release of purifying constraint in certain branches of the gene family tree. Finally, we report expression patterns for five Eschscholzia YABBY genes consistent with functional conservation between early-diverged and core eudicots.

Ancestral expression patterns and evolutionary diversification of YABBY genes in angiosperms

Lateral organ growth in seed plants is controlled in part by members of the YABBY (YAB) and class III homeodomain/leucine zipper (HD-ZIPIII) families of transcription factors. HD-ZIPIII genes appear to play a conserved role in such organs, but YAB genes have diversified, with some members of the family having specialized functions in leaves, carpels or ovule integuments. The ancestral expression patterns and timing of divergence of the various classes of YAB genes remain to be established. We isolated and evaluated the expression of one HD-ZIPIII and five YAB genes representing the five major YAB gene classes from Cabomba caroliniana, a member of the earliest-diverging angiosperms. Consistent with observations in eudicots, the FILAMENTOUS FLOWER (FIL) and YABBY5 (YAB5) genes of C.caroliniana were expressed in the abaxial regions of the leaf where new laminar segments arise, and the patterns of expression were mutually exclusive to those of HD-ZIPIII, indicating that these expression patterns are ancestral. Expression of CRABS CLAW (CRC) in the abaxial carpel wall, and of INNER NO OUTER (INO) in the abaxial outer integument of ovules was also conserved between eudicots and C.caroliniana, indicating that these patterns are primitive. However, the CRC gene was also expressed in other floral organs in C.caroliniana, and expression in stamens was also observed in another early-diverging species, Amborella trichopoda, indicating that carpel-specific expression was acquired after divergence of the Nymphaeales. The expression data and phylogeny for YAB genes suggest that the ancestral YAB gene was expressed in proliferating tissues of lateral organs.

Body and Claw Size At Autotomy Affect the Morphology of Regenerated Claws of the Sand Fiddler Crab, Uca pugilator

Abstract Sand fiddler crab males, Uca pugilator (Brachyura: Ocypodidae), use their single enlarged claw as a weapon in fights for burrows and as a signal to attract females to burrows. Seventy-three males from a South Carolina marsh were in reared in the laboratory to determine if body size at the time of claw loss affects the morphology of the claw that subsequently regenerates. Thirty-six males were induced to autotomize claws and regenerated new ones. Thirty-seven males retained original claws. Across four molts, males regenerating claws gained more in claw length but less in body width and overall mass than males retaining original claws. The first molt accounted for these differences as males regenerating claws gained relatively little in body size but added much in claw length. Regenerated claws were more slender, having smaller dimensions of the manus relative to claw length. As the manus houses the claw closer muscle, regenerated claws are expected to be less powerful and appear more designed for ...

Ecological implications of allometric growth in Brachyurans: Data from <i>Uca Tangeri</i> resident in a West African mangrove swamp

A survey was carried out on the fiddler crabs present in a small naturally defined mangrove swamp in the upper Bonny Estuary of the Niger Delta (S. Nigeria), the purpose of which was to study the ecological significance of the claws of the Ocypodidae crab, Uca tangeri (Eydoux, 1835). Previous studies on the size of the claws of crabs generally have focused on their use in foraging. In the present investigation, the use of claws in reproduction provides further support to the view that evolution of crab chelae (claws) is not driven by feeding requirement alone. Mating pairs collected in the field showed that > 75% of mating males had chelae above the average size of the male population as a whole. Maintenance costs for cheliped in Uca tangeri estimated by respirometry were not significantly different from other body tissues as oxygen uptake could be predicted solely from dry tissue weight. Moreover, the rate of oxygen uptake was independent of the proportion of the total body weight that could be contributed by the chelipeds. Changes in the allometry of various dimensions at sexual maturity was observed in U. tangeri and suggests a sexual role in the crab.KEYWORDS: Relative growth, Uca tangeri; Claw size, Bonny Esturary.