Brachyuran Decapods Research Articles

Geological History of Brachyuran Decapods From New Zealand

Recently completed, comprehensive surveys of the living and fossil brachyurans from New Zealand permit an analysis of the paleobiogeographic history of the group. Among the 18 families known from the modern fauna, 50% are represented in the fossil record. The modern fauna is comprised of fewer family-level taxa than are present in Japan, China, or West Africa, which reflects limited low latitude influence. Development of some elements of the New Zealand brachyuran fauna can be traced into the Cretaceous. As early as the Eocene, a characteristic fauna, with high latitude, temperate affinities, had developed. Tethyan, or tropical and subtropical, taxa are less common than previously presumed. The New Zealand brachyuran fauna was established largely prior to separation of the southern continents and development of the circum-Antarctic current system.

Late Eocene Decapod Crustacea from North Westland, South Island, New Zealand

Eight species of brachyuran decapod crustaceans are recorded from coastal outcrops of Island Sandstone between Perpendicular Point and Punakaiki, Westland, New Zealand. The fauna consists of three raninids—Laeviranina pororariensis (Glaessner), L. keyesi n. sp., Lyreidus bennetti n. sp.; two portunids—Rhachiosoma granuliferum (Glaessner), Pororaria eocenica Glaessner; a goneplacid—Carcinoplax temikoensis n. sp.; and two majids—Leptomithrax griffini n. sp., Notomithrax allani n. sp. Together, they form the most diverse brachyuran assemblage yet described from New Zealand. The decapods are preserved in unusual elliptical masses, with their long axes typically parallel to bedding, containing superbly preserved cuticle often surrounded by well-formed fecal pellets, probably of decapod origin. The accumulations are interpreted to be mechanical concentrations within depressions produced by decapods or associated spatangoid echinoids. Although seven of the species have been recorded only from the Island Sandstone, Rhachiosoma granuliferum (Glaessner) is now known to occur in the correlative deep-water facies of the Kaiata Formation in North Westland, as well as in the Tapui Sandstone, North Otago (middle Eocene), and from coeval rocks at Snowdrift Quarry, southeast Otago. The raninids suggest comparison with congeneric forms from Snowdrift Quarry and the Tapui Sandstone, as well as with the La Meseta Formation, Seymour Island, Antarctica. Based upon associated foraminiferans, a Kaiatan–Runangan (late Eocene) age is assigned to this fauna. The occurrences of Carcinoplax, Leptomithrax, and Notomithrax represent paleobiogeographic and stratigraphic records for the genera.

Estimating biomass and production of pelagic larvae of brachyuran decapods in western European shelf waters

Methods are described for estimating the dry weight biomass, production due to growth, production due to moults, flux to the plankton from the benthos of hatching zoeae and from the plankton to the benthos of settling megalopae of common Brachyura from north-western European waters. These methods are applied to brachyuran larvae taken in Continuous Plankton Records in the Irish Sea during 1981–1983 and from the Longhurst Hardy Plankton Recorder over Great Sole Bank in June 1983. The former provided estimates of input of hatching zoeae to the plankton at 10 m depth from the benthos of 0.41 mg dry weight · m −3 · a −1 with a peak in April, a mean standing stock of 0.19 mg · m −3 with a maximum in May. The peak in production was in July and the annual ratio of production to biomass ( P: B) was 23.2:1 excluding moults, or 26.1:1 including moults. The estimated flux of settling megalopae from the plankton at 10 m depth to the benthos was 1.33 mg · m −3 · a −1 with a peak in July. The data from the LHPR haul gave instantaneous daily values of an input of 0.004 mg · m −2 · day −1 to the plankton and a mean biomass 6.696 mg · m −2 of brachyuran larvae in the plankton. The daily P: B ratio was 0.067:1 excluding moults and 0.073:1 including moults and an estimated 0.07 mg · m −2 · day −1 was returning to the benthos.

Ultrastructure of the mandibular organ of the shrimp, Penaeus japonicus, in untreated and experimentally manipulated individuals

The fine structure of the mandibular organ of the shrimp, Penaeus japonicus, was studied. The cells of mandibular organ contain mitochondria, smooth endoplasmic reticulum and Golgi complex. These organelles do not show any change during molt cycle. Prominent changes were observed in the cells after some steroids or proteinaceous substance. Some changes in the cells also occurred after the eyestalks were ablated. The function of the mandibular organ was considered. Le Roux (1968) described a pair of glandular organs in the cephalothorax of brachyuran decapods. He named them mandibular organs. Since then several studies on the histology and the function of mandibular organs have been published (Aoto et al., 1974, Hinsch and al Hajj, 1975, Byard et al., 1975, Hinsch, 1977, Yudin et al., 1980, Laufer et al., 1984). Nevertheless, the physiological function of the mandibular organ is still unclear. In order to obtain some idea of its function, we performed some experimental procedures with the shrimp, Penaeus japonicus. The results of these experiments are given herein.

Functional morphology of the cuticular terraces in burrowing terrestrial brachyuran decapods

Observations on Gecarcinus lateralis and Ocypode quadrata from Bermuda show that their cuticular terraces are not functional as burrowing sculptures, as previously assumed. Instead, they increase the friction against the walls of the burrow when the animal wedges itself to avoid being extracted by predators. No significant increase in the number of terraces takes place during growth in the size interval available for this study. This is different from the situation described as usual in burrowing decapods, and is rather similar to that of crevice-dwelling crabs. The distribution of terraces and their ontogenetic pattern, therefore, are not reliable indicators of the life habits.

Burrowing habits and cuticular sculptures in recent sand­ dwelling brachyuran decapods from the Northern Adriatic Sea (Mediterranean)

Burrowing habits and cuticular sculptures in recent sand­ dwelling brachyuran decapods from the Northern Adriatic Sea (Mediterranean)

Reduction of Maxillary Endites in Larval Anomura and Brachyura

The typical zoeal maxilla is a structurally complex and highly modified appendage. Although reduced in morphology from the generalized crustacean limb so that it appears to be a single segment, certain features remain distinguishable. Coxal and basal endites, usually bilobed and armed with setae, arise from the protopodite (the fused coxa and basis). A unilobate en dopodite, or palp, extends above (distal to) the basal endite and retains a ''stepped appearance, with groups of setae indicating former segmentation. The scaphognathite, an expanded, flattened lobe fringed with setae, extends laterally from the protopodite. The setation of the endopodite and scaphognathite is of taxonomic value within the Decapoda (Gurney, 1942; Rice, 1980a) as is the shape of the scaphognathite (Van Dover et al., in press), especially within the Anomura and Brachyura. Endite setation is often variable both among species and within a given species (Aikawa, 1929; Gonor & Gonor, 1973), so this feature is of limited taxonomic importance. There are, however, interesting patterns in the degree of endite reduction within the Anomura and Brachyura which I shall discuss below. The extensive literature on the larval development of anomuran and brachyuran decapods includes descriptions and illustrations of the first zoeal maxilla of over 340 species belonging to 31 families. Analysis of these publish ed accounts indicates that well-developed endites (fig. 1A) are by far the most common condition and occur in nearly all of the species in 25 of these 31 families for which the larvae have been described (table I). In the Anomura the most extreme example of endite reduction, to the point where only a simple protopodite exists, is seen in the Hippidae (e.g. Em?rita talpoida (Say, 1817); Rees, 1959). In known larvae of this family the endite setation has been reduced to 3 short, simple setae (fig. IB). A similar reduction occurs in at least one genus of the Albuneidae (Albunea spp.; e.g. Albunea symmysta (L., 1758); Menon, 1937), although in this group the short, simple setae are more numerous than in the Hippidae and are clustered (approximately 11 setae in 3 groups; fig. 1C). In the pagurid Lithopagurus yucatanicus Provenzano, 1968, the galatheid Munidopsis serricornis (Lov?n, 1852) (as M. tridentata; Sars, 1890; Samuelsen, 1972) and the tymolid Cymonomus bathamae Dell, 1971 (Wear & Batham, 1975)

Heart and one gill-bailer rhythm phase couple in Cancer boreaus and Cancer irroratus

1. 1. In two species of brachyuran decapod crustaceans, the rhythmic beating motions of the scaphognathites (SGs) or gill-bailers fell preferentially within distinct points of the heart cycle. 2. 2. An established phase relationship between one scaphognathite movement and the heart beat did not vary over many cycles and remained tightly coupled. 3. 3. During periods of heart and one gill-bailer coupling, changes in oxygen content altered beating rates but did not necessarily affect the degree of phase coupling or the angle of phase preference.

Periodic respiratory and circulatory performance in the red rock crab Cancer productus

AbstractPeriods of simultaneous arrest in both cardiac and scaphognathite (ventilatory) pumps of up to 20 minutes duration occur spontaneously and repetitively in resting restrained Cancer productus. Measurement of cardiac and scaphognathite beat frequencies, ventilation volume, oxygen uptake and circulating blood oxygen tensions indicate that oxygen exchange is more effective in this species than has previously been reported for other brachyuran decapods and compensation for long pauses involves only short periods of moderate hyperventilation and enhanced oxygen uptake. The initiation, importance and control of pausing behaviour is discussed. During periods of repetitive pausing a stereotyped pattern of heart and scaphognathite responses occurs. The pattern is easily modified by such factors as activity and oxygen availability. This study suggests that higher neural control centers coordinate the beating of heart and scaphognathites thus allowing regulation of gas transport and exchange.

Ecology of terrestrial decapod crustaceans on Aldabra

The ecology of the following pagurid and brachyuran decapods on Aldabra is described briefly: Coenobita rugosus, C. perlatus, C. clypeatus, Birgus latro, Geograpsus stormi, G. grayi, Grapsus tenuicrustatus, Cardisoma carnifex, C. frontalis, Ocypode cordimana, O. ceratopthalma. Cardisoma camifex and Birgus latro are the only species which range far from the shore. C. carnifex occurs in very large numbers, especially around freshwater pools. It is largely a detritus feeder. Birgus latro is also common and, though partly predaceous, is often associated with Pandanus , the fruit of which it eats. Coenobita rugosus feeds on the faeces of giant tortoises on the dunes.

On the Motor and Inhibitory Innervation of the Legs of Brachyuran Decapods

Previous articleNext article No AccessOn the Motor and Inhibitory Innervation of the Legs of Brachyuran DecapodsC. A. G. Wiersma and George MarmontC. A. G. Wiersma Search for more articles by this author and George Marmont Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 11, Number 3Jul., 1938 Article DOIhttps://doi.org/10.1086/physzool.11.3.30151464 Views: 1Total views on this site Citations: 2Citations are reported from Crossref Journal History This article was published in Physiological Zoology (1928-1998), which is continued by Physiological and Biochemical Zoology (1999-present). PDF download Crossref reports the following articles citing this article:Theodore J. Wiens Common and specific inhibition in leg muscles of decapods: Sharpened distinctions, Journal of Neurobiology 20, no.55 (Jul 1989): 458–469.https://doi.org/10.1002/neu.480200514C. A. G. Wiersma The inhibitory nerve supply of the leg muscles of different decapod crustaceans, The Journal of Comparative Neurology 74, no.11 (Feb 1941): 63–79.https://doi.org/10.1002/cne.900740106