Influence of physicochemical parameters on burrowing activities of the fiddler crab Uca tangeri at Huelva coast (SW Spain): Palaeoichnological implications (original) (raw)
Related papers
Journal of Crustacean Biology, 2013
The burrowing activity of the only European fiddler crab species, Uca tangeri (Eydoux, 1835), was studied along the shores of the estuary of the Piedra River in Lepe, southwestern Spain. Casting of burrows allowed recognition of their simple, J-shaped to irregular architecture, which displays striking similarities to fossil Pliocene burrows in the same area. The finding of body fossils of U. tangeri in contemporaneous strata indicates these trace fossils are produced by the same species and demonstrate its presence in the eastern Atlantic coast at least for the last three million years. Burrows of U. tangeri are similar to those of other Uca spp. worldwide and also to those of other brachyurans. Their architectural simplicity makes difficult their definitive recognition in the fossil record. Nevertheless, review of existing literature confirms the presence of brachyuran burrows at least since the Cretaceous.
Burrow morphology of three species of fiddler crab (Uca) along the coast of Pakistan
Burrowing by crabs is an important component of their functional role in mangrove biotopes. the Fiddler crab (Uca) is one of the more conspicuous burrowing organisms in the mangrove areas of Pakistan. To evaluate interspecific differences in burrowing behaviour between three species of Uca (U. annulipes, U. chlorophthalmus and U. sindensis), we compared vegetation cover, sediment composition and burrow morphology by using plaster of Paris casts. Five burrow morphology characters were measured (burrow number, depth, length, volume, and diameter of the burrow openings). Nearly all the morphological characters of the burrows differed significantly between species. The burrow morphology variations were correlated with the tidal level (distance from the water mark during low tide), porosity, percent organic matter, vegetation cover and structure of the sediments. The species-specific differences in the burrows cautions against generalizing regarding the functional role of fiddler crabs along the coast of Pakistan.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2010
This study includes three aspects: 1) the ichnotaxonomic treatment of large and dominantly vertical burrows ornamented with sharp bioglyphs from the fluvial Neogene Vinchina and Toro Negro formations (northwest Argentina); 2) the description and interpretation of the sedimentary facies where these burrows occur; and 3) neoichnologic observations on large ornamented burrows from seasonal wetlands of the Río Pilcomayo National Park (Argentina) as possible modern analogues of the trace fossils and the sedimentary environment. A new ichnogenus and ichnospecies, Capayanichnus vinchinensis, is proposed to include the large striated burrows. The new ichnotaxon is distinguished by a combination of a predominantly vertical orientation, overall "L" shape (when fully developed), absence of lining and burrow bifurcation, a distinct surface texture, and lack of burrow enlargements. The hosting sedimentary facies of the Vinchina Formation can be grouped into fluvial channel and splay (floodplain) facies associations. The rivers of that unit were of two main types: single channel rivers with frequent channel avulsion and overbank flow and multichannelised rivers with poorly defined margins. At least some of these rivers were ephemeral or with intermittent discharge. The climate was probably seasonal and semiarid, as suggested by sedimentologic evidence. C. vinchinensis was dominantly recorded from the top of fluvial channels (interpreted as abandoned channels) and proximal, intermediate and distal splay facies. The large ornamented burrows found in an extant comparable example were constructed by freshwater crabs. These burrows can be distinguished by the overall architecture, the taxonomy and sex of its occupants, and the environmental setting where they were found. The neoichnologic signatures used in the interpretation of the fossil example include the common oval burrow cross-section and the surface texture. In particular, the surface texture in the modern crab burrows includes abundant comma-shaped marks, sets of grooves oblique to burrow axis, and long segmented grooves. The predominantly oval cross-section, absence of lining, and the strongly ornamented burrow surface suggest that C. vinchinensis was produced by freshwater crabs. The key features of the surface ornament are long sets of three-four ridges whose width is in average one third of the burrow major axis. Other features that also point to a crab origin are a massive filling, common burrow ends in a casing mudstone, chevron pattern in sets of surface ridges, and possible cheliped marks. The new ichnotaxon is restricted, in the Vinchina and Toro Negro formations, to fluvial facies and is absent in shallow lacustrine facies.
Marine Ecology Progress Series, 2006
The burrowing crab Chasmagnathus granulatus is the most abundant bioturbator in estuarine intertidal sediments from southern Brazil to central Argentina. This crab is a deposit feeder that excavates and maintains large semi-permanent open burrows with funnel shaped entrances. In this study we showed that the funnel shaped burrows with low aspect ratio are the most common and, with field experiments, we demonstrated that these burrows are also the most efficient in the capture of organic matter. As shown by C isotopic signatures, the origin of trapped detrital material is Spartina densiflora. Burrows are distributed in the upper part of estuaries and saltmarshes, mostly in areas of low energy, and cover extensive areas between the marsh vegetation and the open estuary. Through sampling of crab densities and use of satellite images, we estimated the number of burrows of different shapes in the Bahia Blanca estuary (38°50' S), one of the largest estuarine intertidals in the SW Atlantic. After combining this information with the trapping efficiency of burrows of different shapes, we estimated that within 100 d, a crab bed could capture the entire annual production from a marsh area of similar size. Therefore, we suggest that these extensive burrow beds may be considered large macrodetritus retention areas, reducing the amount of organic matter exported from marshes but locally increasing the sediment organic matter content.
Fiddler crabs and their above-ground sedimentary structures: a review
Journal of Ethology, 2020
Fiddler crabs are abundant, semi-terrestrial crustaceans inhabiting tropical, subtropical and warm temperate coasts worldwide. Some species build above-ground sedimentary structures at or near the opening to their burrows. The functions and shapes of these constructions vary interspecifically and according to the sex of the builder. Here, we compile the dispersed reports on these structures, suggest uniform naming for different shapes, review explanations for their functions and explore associations between the attributes of builders and their structures. We found that 47 fiddler crab species build at least one type (or subtype) of structure, including chimneys, hoods, pillars, semidomes, mudballs, and rims. Sedimentary structures show a strong association with sediment type as well as builder front type, genus and sex, but not with fiddler crab clade. Experimental studies have revealed distinct, sometimes multiple functions for some of these structures (e.g., female attraction, red...
Excavation of burrows by fiddler crabs are a crucial component of functional dynamics in mangrove ecosystem. Eleven burrow characters of rosy fiddler crab Uca rosea (Tweedie) were compared between two biotopes in Indian Sundarbans, throughout the year. Substratum qualities and mean shore level were estimated monthly. Mean density and sex ratio was calculated. Multivariate analysis of variance revealed significant differences (P\0.05) in burrow morphology in different size classes of the species and in different seasons. Nine out of eleven characteristics differed between male and female fiddler crabs including burrow diameter (mm), burrow volume (cm3), total burrow length (mm) and depth (mm), chamber diameter (mm), burrow neck height (mm) etc., being larger in males than in females. These can be attributed to the presence of large chelipeds in males. Although, the two sites were different regarding the substratum composition, percent organic carbon and organic matter content, soil pH and shore level, the burrow morphology of rosy fiddler crab followed a fixed pattern that did not change even in different habitat.
Burrows with Chimneys of the Fiddler Crab Uca thayeri: Construction, Occurrence, and Function
Zoological Studies, 2012
Building of soil structures is observed in a variety of semi-terrestrial crustaceans. In fiddler crabs (Genus Uca), this behavior occurs in several species, some of which build structures that are largely ornamental and others construct barriers that are apparently for defense. Although there is a relative abundance of studies on this type of behavior in Uca, the relationship between the social context and the occurrence of these structures remains poorly studied. Thus, this study attempted to analyze in detail the construction, occurrence, and function of mud chimneys built by the fiddler crab Uca thayeri; these sedimentary structures are possibly associated with burrow defense. Field investigations and laboratory experiments were conducted. Both sexes were often found in burrows with chimneys; however, laboratory experiments showed that only females actively built and maintained chimneys, with some difference in the morphology of these structures between sexes. The social context ...
New occurrences of Sinusichnus sinuosus described in the Cenozoic of Spain evidence the almost continuous fossil record of this ichnospecies from the Upper Cretaceous to the Lower Pliocene. Morphological and size features of these highly regular sinusoidal burrows have been analyzed, showing a very recurrent constructional pattern through time. Such features are also constant along the ontogeny of the producer. The large number of similarities that this ichnogenus shares with fodinichnial burrow systems, such as Thalassinoides, Ophiomorpha, or Spongeliomorpha, point to a crustacean authorship. Since this sinusoidal architecture is also common among some graphoglyptids, other behavioral strategies are discussed. The ichnogenus Sinusichnus occurs commonly in shallow marine environments, in particular to deltaic depositional settings.
Journal of Crustacean Biology, 2015
The burrows excavated by male Uca annulipes at a lagoonal shore on Pulau Hantu Besar, an offshore island of Singapore, are generally less acutely bent, i.e., have significantly smaller mid-angles, than the burrows of females. In an ex situ study, burrows dug by males with the major cheliped removed, and by males with intact major cheliped, were cast with wax. Seven non-angular burrow morphological parameters (burrow diameter, total burrow depth, burrow neck height, curved burrow length, horizontal length, chamber diameter and burrow volume) and two angular variables (mid-angle and ground-angle) were compared to determine if sexual dimorphism in burrow curvature was due to the effect of the major cheliped on burrow excavation. A similar experiment using females with two intact chelipeds and one cheliped removed was conducted to determine if male crabs without the major cheliped dug burrows with dimensions similar to those of females with one cheliped removed. Mean mid-angle of burrows (± SE) was 24.9 ± 1.3°and 16.0 ± 1.0°for males whose major chelipeds were removed and with major intact chelipeds, respectively. Of all the burrow morphological parameters, only the mean mid-angle differed significantly between the two groups of crabs. Female crabs (with and without cheliped removal) did not excavate significantly different-shaped burrows (mid-angles: 20.7 ± 2.1°and 18.2 ± 1.5°, respectively) suggesting that removal of cheliped did not affect burrow architecture. The curvature of the burrows of males that had the major cheliped removed was not significantly different from those of females with one cheliped removed (mid-angles: 24.9 ± 1.3°and 20.7 ± 2.1°, respectively). Results of the study showed that the major cheliped in a male U. annulipes is most likely to be responsible for the sexual dimorphism in curvature of the burrows.