Antennular Segment Research Articles

On a Tropical Subspecies of Monstrilli Wandelii (Copepoda, Monstrilloida) From the Mexican Coasts of the Caribbean Sea

AbstractFrom plankton samples taken at a reef lagoon off Puerto Morelos, on the northern portion of the eastern coast of the Yucatan Peninsula, a new tropical subspecies of Monstrilla wandelii, only known from temperate-cold latitudes, is described from male specimens. The analysis of the main characteristics in the taxonomy of monstrilloids allowed its identification as M. wandelii. The new subspecies differs from the nominal species in the relative length and armature of the antennular segments, in the structure of the genital lappets of the fifth legs and in its total size, which is nearly 2.5 times that of the nominal subspecies.

NEW SUPERFAMILY OF CALANOIDA (COPEPODA) FROM AN ANCHIALINE CAVE IN THE BAHAMAS

ABSTRACT A new calanoid copepod, Fosshagenia ferrarii, new genus, new species, was found in plankton samples collected in an anchialine cave of Caicos Islands, Bahamas. A combination of features found in this species separates it as the type of a new superfamily. The new taxon can be distinguished by a combination of several relevant taxonomic characteristics, such as the fusion of antennular segments 8 and 9, the right antennule modified in the male, less than 3 endopodal segments on the first legs, the presence of a uniramous female fifth leg, a male fifth leg forming a complex grasping organ, reduced mouthparts, and the presence of only 1 seta on the middle endopodal segment of legs 3 and 4. The new taxon appears to be more closely related to fresh- and brackish-water forms (Centropagoidea) than to any other hitherto known anchialine copepod group. The type species can be distinguished by the presence of lateral processes on the genital double-somite of the female and on the first urosomal somite of the male. It is the smallest of the known anchialine calanoid species. This small species, a predator in the water column, diverges from other anchialine copepods which are bottom-dwellers.

REDESCRIPTION OF FEMALE AND MALE MESOCYCLOPS EDAX FORBES, 1891 (COPEPODA: CYCLOPOIDA)

ABSTRACT The female and male of Mesocyclops edax Forbes, 1891, are redescribed. This species comprises the following peculiarities compared to other representatives of Mesocyclops: a broad and deeply serrate hyaline membrane along the distal seventeenth antennular segment; the intercoxal plates of legs 1-3 with tiny spinules; leg 4 bearing 2 small protuberances; the inner seta of leg 4 endopod III nearly as long but smaller than the outer seta; a shovellike shape of the caudal setae; groups of hairs on the inner rim of the caudal rami; the shape of the genital field; and caryological and naupliar peculiarities. The present note provides the first description of the male. The male exhibits sexual dimorphism in size, the habitus, and the morphology of the antennule, antenna, leg 5, and leg 6. Morphological characters are compared and reevaluated with findings in the literature.

Scanning electron microscopy of the fourth antennular segment ofBalanus amphitrite amphitrite

Despite extensive studies on settlement of the cypris larva ofBalanus amphitrite amphitriteDarwin (Crustacea: Cirripedia), the fine structure of the putative settlement receptors of this species has not been described. This study presents observations made with the scanning electron microscope of the fourth antennular segment and its associated setae.

Antennular Withdrawal Motoneurons in the Lateral Antennular Neuropil of Callinectes sapidus

ABSTRACT Antennular withdrawal behavior in Callinectes sapidus can be initiated by stimulating antennular sensory nerve IIIc, and monitored as fictive withdrawal in antennular motor nerve IA. Five motoneurons have been identified with neurites located predominately in the lateral antennular neuropil that contribute to this behavior. These motoneurons exhibited a range of evoked response following stimulation of nerve IIIc. The duration of the excitatory component of the evoked response was appropriate for the role of each motoneuron in producing antennular withdrawal. When depolarized by the intracellular injection of current, each of these cells produced a stereotypical movement of one antennular segment. Motoneurons 26-f and 26-s displaced the medial antennular segment laterally, positioning the entire antennule in a protective cephalothoracic groove. Motoneuron 27 rotated the medial segment about its long axis, while motoneuron 28 displaced the medial segment toward the midline. The movement of the medial segment produced by motoneuron 28 was antagonistic to movements produced by motoneurons 26-f and 26-s. Motoneurons 26-f, 26-s, 27, and 28 were active during the early phase of withdrawal and may establish a consistent initial position of the medial segment prior to placement of the antennule in its final protected location. Motoneuron 30―1f, also active during the early phase of withdrawal, elevated the distal segment as the initial position of the medial segment was being established.

ANTENNULAR WITHDRAWAL MOTONEURONS IN THE LATERAL ANTENNULAR NEUROPIL OF CALLINECTES SAPIDUS

Antennular withdrawal behavior in Callinectes sapidus can be initiated by stimulating antennular sensory nerve IIIc, and monitored as fictive withdrawal in antennular motor nerve IA. Five motoneurons have been identified with neurites located predominately in the lateral antennular neuropil that contribute to this behavior. These motoneurons exhibited a range of evoked response following stimulation of nerve IIIc. The duration of the excitatory component of the evoked response was appropriate for the role of each motoneuron in producing antennular withdrawal. When depolarized by the intracellular injection of current, each of these cells produced a stereotypical movement of one antennular segment. Motoneurons 26-f and 26-s displaced the medial antennular segment laterally, positioning the entire antennule in a protective cephalothoracic groove. Motoneuron 27 rotated the medial segment about its long axis, while motoneuron 28 displaced the medial segment toward the midline. The movement of the medial segment produced by motoneuron 28 was antagonistic to movements produced by motoneurons 26-f and 26-s. Motoneurons 26-f, 26-s, 27, and 28 were active during the early phase of withdrawal and may establish a consistent initial position of the medial segment prior to placement of the antennule in its final protected location. Motoneuron 30―1f, also active during the early phase of withdrawal, elevated the distal segment as the initial position of the medial segment was being established.

L'Origine Protocéphalique De La Carapace Chez Les Thermosbaenacés, Tanaidacés, Cumacés Et Stomatopodes

AbstractThis study deals with the formation of the carapace in Malacostraca which have the last thoracic segments free. In all of them, the three gnathal cephalomeres are dorsally split open whereas this phenomenon affects only a few thoracomeres: the first and part of the second in the thermosbaenacean Monodella argentarii; the first and the second in the tanaidaceans Allotanais hirsutus and Apseudes spectabilis; the first, second and third in the cumacean Heterocuma intermedia, the last two being moreover stretched. The pseudozoean stages of Stomatopoda are slighty different: only the first thoracomere is partly split open and connected by epimera to the sides of the carapace which extends as far as the fourth thoracomere; the last four thoracomeres are exposed. The organization differs in the protocephalic area. In Thermosbaenacea, Tanaidacea and Cumacea which have sessile eyes or arc blind, the protocephalon is undivided. In Stomatopoda which have stalked eyes, the ocular and antennular segments are differentiated as previously observed in other Podophthalmata; that allows to observe that the carapace is produced by the sole antennal segment. Hence, the origin of the carapace is the same in all Malacostraca: it is a dorsal expansion of the protocephalic area (antennal segment when differentiated) which splits and pushes aside the gnathal cephalic tergites and a variable number of thoracic tergites. The tergites play absolutely no role in this formation, either by fusion or by coalescence.

Flicking in the Lobster Homarus americanus: Recordings from Electrodes Implanted in Antennular Segments.

I. Grassle, J. P., and J. F. Grassle. 1976. Science 192: 567-569. 2. Butman, C. A., J. P. Grassle, and C. M. Webb. 1988. Nature 333: 771-773. 3. Grade, J. F., and J. P. Grassle. 1977. Pp. 177-189 in Ecology ofMarine Benthos, B. C. Coull, ed. Univ. SC. Press. 4. Hill, S. D., J. P. Grassle, and M. J. Ferkowicz. 1987. Biol. Bull. 173: 430. 5. Hill, S. D., M. J. Ferkowics, and J. P. Grassle. 1988. Biol. Bull. 175: 311. 6. Murphy, S. D. 1986. Pp. 519-581 in Casarett and DouN’s Toxicology, 3rd ed, J. Doull, C. D. Klaassen, and M. 0. Amdur, eds. 7. Menzer, R. E., and J. 0. Nelson. Pp. 825-853 in Casarett and Doull’s Toxicology, 3rd ed., J. Doull, C. D. Klaassen, and M. 0. Amdur, eds. 8. Nelson, L. 1987. Biol. Bull. 173: 327. 9. Nelson, L. 1990. Bull. Eviron. Contam. Toxicol. 45: 876-882.

Role of Olfaction in Recognition of Dominance in the American Lobster (Homarus americanus).

Previous articleNext article No AccessARTICLESRole of Olfaction in Recognition of Dominance in the American Lobster (Homarus americanus)C. Karavanich and J. AtemaC. Karavanich Search for more articles by this author and J. Atema Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 181, Number 2October 1991 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv181n2p359 Views: 46Total views on this site Citations: 6Citations are reported from Crossref Copyright © 1991 by Marine Biological LaboratoryPDF download Crossref reports the following articles citing this article:S. I. Cromarty, J. Mello, and G. Kass-Simon Time in Residence Affects Escape and Agonistic Behavior in Adult Male American Lobsters, The Biological Bulletin 196, no.11 (Sep 2016): 105–112.https://doi.org/10.2307/1543172 P. Bushmann and J. Atema A Novel Tegumental Gland in the Nephropore of the Lobster, Homarus americanus: A Site for the Production of Chemical Signals?, The Biological Bulletin 185, no.22 (Sep 2016): 319–320.https://doi.org/10.1086/BBLv185n2p319 L. J. Kaplan , C. Lowrance , J. Basil , and J. Atema The Role of Chemical and Visual Cues in Agonistic Interactions of the American Lobster, The Biological Bulletin 185, no.22 (Sep 2016): 320–321.https://doi.org/10.1086/BBLv185n2p320 C. Karavanich and J. Atema Agonistic Encounters in the American Lobster, Homarus americanus: Do They Remember Their Opponents?, The Biological Bulletin 185, no.22 (Sep 2016): 321–322.https://doi.org/10.1086/BBLv185n2p321K. Berg, R. Voigt, and J. Atema Flicking in the Lobster Homarus americanus: Recordings from Electrodes Implanted in Antennular Segments, The Biological Bulletin 183, no.22 (Sep 2016): 377–378.https://doi.org/10.1086/BBLv183n2p377P. B. Armstrong, M. T. Armstrong, and J. P. Quigley A Hemolytic Activity in the Blood of the American Horseshoe Crab, Limulus polyphemus that Resembles the Mammalian Complement System, The Biological Bulletin 183, no.22 (Sep 2016): 378–379.https://doi.org/10.1086/BBLv183n2p378

A new harpacticoid copepod family collected from Australian sponges and the status of the subfamily Rhynchothalestrinae Lang

A new family is proposed for Hatnondia superba gen. et sp. nov., a shield-shaped harpacticoid collected from washings of sponges from Port Phillip, Australia. It is concluded that the closest relatives of the Hamondiidae fam. nov. currently belong to the heterogeneous thalestrid genus Rhynchothalestris Sars, 1905 and for that reason the latter is revised. Rhynchothalestris rufocincta (Brady, 1880) is redescribed and designated as type species for Ambunguipes gen. nov., comprising also the Indo-Pacific A. similis (A. Scott, 1909) which is re-instated. Ambunguipes vanhoeffeni (Brady, 1910) is ranked as species inquirenda within the genus. Because of its body ornamentation R. cornuta Geddes, 1969 is transferred to Lucayostratiotes gen. nov. The Ambunguipedidae fam. nov., accommodating Ambunguipes and Lucayostratiotes are regarded as the sister-group of the Hamondiidae on the basis of the loss of the seta on the first antennular segment, the presence of bifid spinules on the antennary exopod, the presence of a modified seta on the maxillary precoxal endite, the sexual dimorphism of leg 3, the detailed structure of the female genital complex, and the asymmetry of the male P6. The diagnosis of the subfamily Rhynchothalestrinae, encompassing the genera Rhynchothalestris and Peltthestris Monard, 1924 is amended, and a redescription of the former's type species R. helgolandica (Claus, 1863) is presented. The genus also contains R. tenuis Chislenko, 1971 and R. campbelliensis Lang, 1934 grad. nov. which is elevated to full species rank. The inadequately described R. tenuicornis (Brady, 1910) is ranked as species inquirenda. The monotypic genus Peltthestris is regarded as a valid genus. It is suggested that the Rhynchothalestrinae represent an early offshoot in the evolution of the Thalestridae and that the Thalestrinae and the Dactylopusiinae are more closely related to each other than to any other subfamily. Rhynchothalestris agigensis Serban, 1959 has no close relationship with either the Rhynchothalestrinae or the Ambunguipedidae and is tentatively considered incertae sedis within the Dactylopusiinae. The discovery of/, superba and the redescription of A. rufocincta have raised the maximum number of antennular segments in male harpacticoids to 14. The terms ‘epicopulatory bulb’ and ‘epicopulatory plate’ are coined for peculiar structures of the female genital complex. The development of'setoid elements' versus addition of novel setae is briefly mentioned.

A new family of harpacticoid copepods and an analysis of the phylogenetic relationships within the Laophontoidea T. Scott

A new family Cristacoxidae is proposed to accommodate the monotypic genera Cristacoxa gen. nov., Noodtorthopsyllus Lang (ex Canthocamptidae) and Cubanocleta Petkovski (ex Laophontidae). Cristacoxa petkovskii gen. et spec. nov. is described on the basis of a single male collected from coralline sand of Bonaire, West Indies. N. psammophilus Noodt and C. noodti Petkovski are redescribed and refigured on the basis of new material from the Galápagos (Isla Santa Cruz), the West Indian Islands (Curaçao, Klein Curaçao, Bonaire) and the Canary Islands (El Hierro, Tenerife). The new family is characterised by the presence of an outer spinous process on the first antennular segment, the absence of the antennary exopod, the uniramous mandibular palp, the presence of conspicuous cristae on the precoxa and coxa of leg 1 and the elongation of the apical exopodal spines of P2 to P4. The Cristacoxidae are unique in having an equal number of setae/spines onthe P5 in both sexes. Examination of the ontogeny of this leg in males and females of Orthopsyllus spec. gives strong evidence that the cristacoxid P5 has undergone neotenous evolution. Males of Cristacoxidae are readily recognisable by their extremely long spermatophores. The new family is allocated to the superfamily Laophontoidea T. Scott, together with the Laophontidae T. Scott, the Laophontopsidae Huys & Willems, the Orthopsyllidae Huys and the Adenopleurellidae Huys. A phylogenetic analysis of the relationships within the superfamily is presented, and as a result Por’s (1986) concept of the Laophontoidea is refuted. Instead, it is concluded that the superfamily can be defined on the basis of the following apomorphies: (1) antennules with outer spinous process on segment 2; (2) antenna with allobasis bearing 1 seta; (3) antennary exopod quadrisetose; (4) P1 exopod without inner seta on exp-2 and 4 setae/spines on exp-3; (5) P1 endopod 2-segmented with elongated enp-1 and 2 elements on enp-2; (6) P2—P4 with 2-segmented endopods; exp-1 without inner seta; (7) sexual dimorphism of P3 endopod; (8) P6 bisetose with one member fused to somite. There is no close relationship neither with the Normanellidae Lang, nor with the Ancorabolidae T. Scott. The Laophontidae are considered the first offshoot in the evolution of the Laophontoidea because of the retention of the 8-segmented antennule in both sexes and the ancestral seta formulae on P2–P4. The other families can be assigned to two clades: the Adenopleurellidaeand the Laophontopsidae-Cristacoxidae- Orthopsyllidae-grouping. The Laophontopsidae and the Cristacoxidae are sister groups because of the shared sexual dimorphism of the P3 endopod (advanced type), and the fusion of antennular segments distal to the geniculation in the male. Emphasis is placed on the postembryonic development in the Laophontoidea of the male P3 endopod and P6 and on their homologies in the female. A reconstruction of the hypothetical ancestor of the Laophontoideais presented.

Cypris Ultrastructure, Metamorphosis and Sex in Seven Families of Parasitic Barnacles (Crustacea: Cirripedia: Rhizocephala)

AbstractCypris morphology in the Rhizocephala differs both between the sexes of individual species and between the species. The large aesthetasc on the third antennular segment is unique to male cyprids of the Lernaeodiscidae, Peltogasteridae and Sacculinidae (suborder Kentrogonida) and Mycetomorpha vancouverensis (suborder Akentrogonida). A fourth segmental aesthetasc, common to both sexes, is much longer in males than in females. A spinous process on the attachment disc is another male‐specific character, but is absent altogether in the Lernaeodiscidae.It is argued that these aesthetascs help locate the settlement targets.Except in Mycetomorpha vancourverensis, aesthetascs have been secondarily lost in cyprids of the suborder Akentrogonida, and there are no other morphological means for separating the male and female settling stage. In cyprids of Sylon hippolytes (Sylonidae) and of Mycetomorpha vancouverensis and Thompsonia sp. (Akentrogonidae) the long and slender antennules are probably used in penetration without formation of a kentrogon, as already reported for Clistosaccus paguri (Clistosaccidae). Cyprids of Sylon hippolytes and Clistosaccus paguri are almost morphologically identical.

Revision of the African species of the genus Mesocyclops Sars, 1914 (Copepoda: Cyclopidae)

A revision is made of the African Mesocyclops species, based on type material (when extant) and on collections from various parts in Africa. Diagnostic characteristics are: presence or absence of spinule patterns on antennular segments, structure of the hyaline membrane of the 17th antennular segment, spine pattern on the basipodite of the antenna, armature of the maxillulary palp, presence or absence of a spine on the basipodite of P1, armature of the connecting lamella, coxopodite and basipodite of P4, armature of the apical spines of Enp3P4, armature of the last thoracic segment, genital segment and the other abdominal segments, armature of the furcal rami and structure of the receptaculum seminis. First, the taxonomical status of M. leuckarti (Claus) is redefined; this species does not occur in Africa and its geographical range is restricted to Europe and the western part of Northern Asia. On the African continent, twelve other taxa are found. Four are described as new to science: M. kieferi sp.n., M. dussarti sp.n., M. spinosus sp.n. and M. aequatorialis similis subsp.n. The remainder are: M. major Sars, M. tenuisaccus (Sars), M. paludosus Lindberg, M. salinus Onabamiro, M. ogunnus Onabamiro, M. aspericornis (Daday), M. rarus Kiefer and M. aequatorialis aequatorialis (Kiefer). Their geographical distribution is discussed. Eleven taxa are restricted to the African continent (including the Arabian Peninsula and the Canary Islands). One taxon is also found in the Oriental Region. Madagascan representatives are briefly mentioned. The importance of breeding and cross-breeding experiments should be stressed in copepod taxonomy. Experiments were performed on African species and M. leuckarti to evaluate the morphological characters used in the present study, and intraspecific morphological variability was examined up to and including the third generation (Van de Velde, in press). In future one should critically reconsider the so-called cosmopolitan species; they may indeed represent a complex of related taxa, each with a geographical range more restricted than that of the species-complex itself.

Fine structure and molting of aesthetasc sense organs on the antennules of the isopod, Asellus aquaticus (Crustacea).

In Asellus aquaticus certain distal antennular segments bear single sensilla referred to as aesthetascs. These show a proximal stem and a distal bulbous region. Depending on its position, each aesthetasc is innervated by either 50-60 or 70-80 bipolar sensory cells, the perikarya of which are situated within the pedunculus. Within the antennular segment the dendrites develop unbranched cilia (9 X 2 + 0 structure). The sensory cells are unusual in that mono- as well as biciliary dendrites are present within a single aesthetasc, the ratio of both types being correlated with the number of sensory cells. Cilia and receptor lymph cavity are enveloped by a set of 3-4 inner and 13-14 outer sheath cells, which terminate at the base of the sensillum, so that the delicate and poreless cuticle of the bulbous region encloses only outer segments within the receptor lymph fluid. A new molting type in arthropods is described in which the outer sheath cells alone build the new cuticle, whereas the inner sheath cells most probably have a protective function. A definition of aesthetascs is proposed based on fine-structural criteria. Functionally the sensilla are considered to be chemoreceptors. This assumption is confirmed by experiments with diluted vital dye as well as lanthanum showing that dissolved substances penetrate the poreless cuticle instantaneously.

Morphological and physiological characteristics of the antennular short hair sensilla of the blue crab,Callinectes sapidus

The four short hair sensilla (SHS) on the proximal antennular segments of Callinectes sapidus consist of a tapered shaft covered on all but the inner surface with unbranched hairs. Waterborne mechanical stimuli do not excite the SHS, whereas antennular movement evokes high amplitude activity in afferent fibers. Phasic sensory elements from the anteriormost sensillum respond primarily to anteroventral deflection, while the other three sensilla contain sensory elements which respond to posteroventral deflection. The similarity of SHS to the Type I long hair sensilla of the cockroach trochanteral plate suggest they perform a comparable movement‐limiting function. The SHS may also interact with afferent activity from the statocysts.

Statolith implantation in the banana prawn Penaeus merguiensis

Specimens of Penaeus merguiensis de Man were captured between February and May 1981 from intertidal creeks and beaches of Cleveland Bay, Townsville, Australia, using a 15 m seine net. The statocyst of P. merguiensis resembles that of other macrurans in that it is a dorsal invagination of the basal antennular segment lined with groups of sensory hairs. The statolith is composed of sand grains implanted by the prawn from the substratum which must be done after every moult. Implantation begins within 90 min of ecdysis and has 3 phases: sifting; digging and finally eye withdrawal which pushes the sand grains into the statocyst chamber.

Structures Chemoreceptrices Des Antennules Du Crabe Carcinus Maenas (L.) (Decapoda Brachyura)

Four types of sensory hairs have been identified on the antennules of Carcinus maenas: aesthetascs, guard hairs, short and long mechanoreceptors. Furthermore sensory areas are located in small cuticular cavities. The aesthetascs are implanted on most of the antennular segments; they do not display any sexual dimorphism during growth. Each is innervated by a particular ganglion, the axons of which join the antennular nerve. Although cuticular permeability is very striking, no pores could be observed. The aesthetascs seem well adapted for chemoreception; the other hairs for mechanoreception.

Nanogalathea Raymondi, a New Genus and Species of Galatheidae (Decapoda, Anomura) From the Bay of Bengal

Nanogalathea raymondi new genus and species is described for two females from the Bay of Bengal collected during the IIOE Expedition. The genus is quickly diagnosed by the absence of the rostral teeth; pyramidal spine on the outer orbital angle, shape and armature of the basal antennular segment and the shape of the third thoracic sternites. Relationship of the genus with closely allied genera is discussed.

Trois nouvelles especes du genre mixtacandona (ostracoda, cyprididae, candoninae)

The authors describe Mixtacandona elegans n. sp.,M. pietrosanii n. sp., M. tabacarui n. sp. and present new data on the systematics and biogeography of the following Mixtacandona groups: ljovuschkini,hvarensis and riongessa. Mixtacandona elegans n. sp. belongs to the group ljovuschkini. The carapace is very elongated and has markedly assymetrical valves. The species has been found in a porous aquifer in southeastern Bulgaria. M. pietrosanii n. sp. belongs to the group hvarensis. The 3rd antennular segment and the 2nd endopodial segment of the cleaning leg have each two setae. The species lives in porous aquifers in the Danube plain in Roumania. M. tabacarui n. sp. (gr. riongessa) has a triangular left valve with a pointed dorsal protuberance. The species has been found in wells fed by karstic water in southern dobrodgea (Roumania), on the Black Sea coast.

Morphological characters of taxonomical importance in Cryptoniscina (Isopoda Epicaridea) A scanning electron microscopic study of Cryptoniscus Larvae

Abstract By means of scanning electron microscopy, several morphological characters have been investigated in a large number of cryptoniscus larvae, representing all the 7 families of the Cryptoniscina. However, with the present subdivision of the taxon, features characterizing the entire superfamily or the different species were easier to settle than those of the generic or family levels. The number and arrangement of setae on the two proximal antennular segments, the number of segments of the antennal peduncle and flagellum, as well as their setation, and the number and position of setae on the different segments of the pleopods, are all characters of the super-family. Presence or absence of posterior teeth on the antennular plate is a family character, with the exception of Cabiropsidae, while the number of these teeth generally can be used at the generic level. However, in one genus, Cyproniscus, they even showed an intraspecific variation in number. Apart from the Hemioniscidae, the presence or absen...