Showing papers in "Journal of Crustacean Biology in 1982"
TL;DR: In another part of the study involving competition for preferred substrate, little displacement occurred even at high densities; caution is suggested in assessing the importance of aggressive interactions to species displacements.
Abstract: Aggressive interactions and competition for shelter were studied in simplified laboratory environments among the crayfish Orconectes virilis, O. propinquus, and O. rusticus. O. rusticus was clearly superior to O. virilis, with O. propinquus generally intermediate. These results are consistent with ongoing displacements in northern Wisconsin. However, in another part of the study involving competition for preferred substrate, little displacement occurred even at high densities; caution is therefore suggested in assessing the importance of aggressive interactions to species displacements.
176 citations
TL;DR: Compared with warmer water populations in southern Britain and Holland, the Maine coast population of C. maenas has later settlement of megalopae, slower growth, delayed maturity, longer generation time, and a longer life span, which may account for the inability of populations to establish themselves in waters much colder than those of the central coast of Maine.
Abstract: Along the central coast of Maine most female Carcinus maenas extruded their eggs in spring. The smallest ovigerous female was 34 mm in carapace width. Mating occurred from July to October, and in all mating pairs the male was larger than the female. Megalopae and Stage 1 crabs did not settle until late August, growing only to a mean of 5.5 mm carapace width (Stage 5) before winter. Renewed growth began the following June, and juveniles grew to 13-25 mm carapace width by their second winter. Most mature males molted by the end of July, whereas mature females molted from July to October, while guarded by males waiting to mate with them. On the central coast of Maine, therefore, C. maenas matures when 2-3 years old, breeds 2-3 times, and generation time is a minimum of 3 years. Compared with warmer water populations in southern Britain and Holland, the Maine coast population of C. maenas has later settlement of megalopae, slower growth, delayed maturity, longer generation time, and a longer life span. Such differences may account for the inability of populations to establish themselves in waters much colder than those of the central coast of Maine. The northern limits of the range of the green shore crab Carcinus maenas in the Gulf of Maine have reflected the periodic warming of the surface waters that occurred in the Gulf during the 1930's, 1950's and 1970's. During the warmer years the numbers of C. maenas increased in the northeastern part of the Gulf, but during the intervening colder years their numbers declined again and they then became uncommon north of the coast of central Maine (Welch, 1968, 1979). Do colder than average temperatures slow growth and delay larval recruitment to an extent sufficient to restrict the species from permanent or extensive colonization of the northern Gulf? The life cycle of C. maenas on the North American coast has not been examined in detail. Most accounts of its life cycle have described populations on the coasts of Britain and Holland (Broekhuysen, 1936; Crothers, 1967, 1968, 1970; Klein-Breteler, 1975a, b, c, 1976a, b) where water temperatures average 4-5?C warmer than on the coast of central Maine. The purpose of the present study is to compare the life cycle of C. maenas on the coast of central Maine with that of the populations from warmer waters as a way of assessing the ability of the species to penetrate cold-temperate regions.
150 citations
TL;DR: It is shown that a substrate with preformed crevices is preferred for settling, but other substrates can be manipulated to make suitable burrows, and field observations that lobsters can successfully exploit a variety of substrates are confirmed.
Abstract: During the molt from third- to fourth-stage, larvae of Homarus americanus metamorphose into their adult form and pigmentation. In the course of the fourth stage, their pelagic life changes to a benthic existence. Artificial substrate choice experiments and qualitative illumination experiments show that during the early fourth stage the phototactic response reverses from positive to negative. Together with positive thigmotaxis, this results in a choice of dark crevices. Among natural substrate choices, preferential settlement occurred on macroalgal-covered rocks, followed by rocks on sand, mud, and sand. Moreover, when no choice was given, settling occurred most rapidly on macroalgal-covered rocks (34 h), followed by scattered rocks on sand (38 h), and mud (62 h); no settling occurred on sand even two weeks after the last animal had settled on all other substrates. These animals continued to explore the sand substrate with dives to the bottom. Although mud was not a preferred substrate in choice tests, the animals that chose mud and those that were presented only with mud settled successfully and were immediately efficient in their burrowing behavior, constructing U-shaped tunnels even in the center of the aquarium without using a pebble or rock as a starting point. These laboratory tests confirm field observations that lobsters can successfully exploit a variety of substrates. They show that a substrate with preformed crevices is preferred for settling, but other substrates can be manipulated to make suitable burrows.
133 citations
TL;DR: Sensilla sensitive to mechanical but not to chemical stimuli include peg sensilla, which are small sensilla situated in articulated sockets within cuticular depressions and are distributed over the surface of the carapace, pereiopods, and maxillipeds, and mechanoreceptive sensilla include cuticular articulated peg organs (=CAP organs).
Abstract: Chemosensory neurons and mechanosensory neurons innervate all the cephalothoracic appendages of the lobster Homarus americanus, including the antennules, antennae, six pairs of mouthparts, and five pairs of pereiopods. The structure and sensory function of sensilla on these appendages are described. Sensilla on the pereiopods and maxillipeds can be classified morphologically and physiologically. Smooth setae and squamous setae are the primary setal types in the rows and tufts of hairs on the walking legs; they also are found on the maxillipeds and, less abundantly, on the crusher and seizer claws. Serrate setae are common on the maxillipeds and the third and fourth walking legs. Hedgehog hairs are located on the cutting edges of the claws of the first two pairs of walking legs and on apposable cuticular surfaces on the last two segments of the fourth pair of walking legs. All four of these types of sensilla are both mechano- and chemosensitive. Sensilla sensitive to mechanical but not to chemical stimuli include peg sensilla, which are small sensilla situated in articulated sockets within cuticular depressions and are distributed over the surface of the carapace, pereiopods, and maxillipeds. Other mechanoreceptive sensilla include cuticular articulated peg organs (=CAP organs), located on the pereiopods and on the third maxillipeds, and campaniform sensilla, found on the antennae and antennules. Exclusively chemosensory sensilla were not found.
123 citations
TL;DR: Four developmental stages are defined for the cement glands of mature female American lobsters, which are tegumental glands that cycle in phase with ovary development and secrete a substance that appears to be involved in the egg fertilization-attachment process.
Abstract: Four developmental stages are defined for the cement glands of mature female American lobsters. These "cement glands" are tegumental glands that cycle in phase with ovary development and secrete a substance that appears to be involved in the egg fertilization-attachment process. Since cement glands do not develop in male or immature female lobsters, they can be used to determine maturity in females that are not ovigerous. In wild populations, size at maturity is frequently based on sizes of ovigerous females, but this assessment is complicated by the existence of two different reproductive patterns in the Adult-I year, the fact that only half of the mature females are ovigerous in any year, and the fact that ovigerous females often are not adequately sampled by traditional trapping procedures. Cement gland development can be used to improve the accuracy of maturity assessments by providing information on maturity of barren females.
68 citations
TL;DR: Alvinocaris lusca, a new genus and species of caridean shrimp, is recorded from the thermally influenced Rose Garden area of the Galapagos Rift zone.
Abstract: Alvinocaris lusca, a new genus and species of caridean shrimp, is recorded from the thermally influenced Rose Garden area of the Galapagos Rift zone. Characters of this form indicate placement in the family Bresiliidae which is redefined. A key to the 5 bresiliid genera is given.
65 citations
TL;DR: It is demonstrated that chemical cues are important in species recognition in the crayfishes Orconectes propinquus and OrconECTes virilis and males and females of both species can perceive the chemicals released from their own and the other species.
Abstract: Laboratory experiments demonstrate that chemical cues are important in species recognition in the crayfishes Orconectes propinquus and Orconectes virilis. Males and females of both species can perceive the chemicals released from their own and the other species and are attracted only to the chemicals of conspecifics of the opposite sex.
55 citations
TL;DR: Shrimps of the families Sergestidae and Palaemonidae collected in the Orinoco basin, the upper Cuyuni River, and the upper and lower Rio Negro, are dealt with in this paper.
Abstract: Shrimps of the families Sergestidae and Palaemonidae collected in the Orinoco basin, the upper Cuyuni River, and the upper and lower Rio Negro, are dealt with in this paper. New records and comments are given for Acetes paraguayensis, Macrobrachium amazonicum, M. brasiliense, M. jelskii, M. nattereri, M. surinamicum, and Palaemonetes carteri. Two new palaemonids are described: Macrobrachium cortezi, a form related to M. nattereri, from several localities in the Orinoco River and upper Rio Negro, and M. aracamuni, from an altitude of 680 m in the Cerro Aracamuni in the drainage area of the upper Rio Negro. Another previously undescribed species of Macrobrachium is recorded but not named due to the lack of mature males. The Guayana highland is an ancient land mass extending from the Amazon River to the Atlantic coast of South America and includes the Guianas and parts of Venezuela and Brazil. The Venezuelan Guayana comprises 41,300 km2 of territory, mostly above 400 m that separate the Orinoco from the Amazon basin and forms a formidable barrier to the dispersion of the fresh-water fauna of the lowlands. The hydrology of the zone is defined by the Orinoco River that bounds the area to the west and north and its tributaries that generally flow north or northwesterly. A smaller portion to the east is drained by the Cuyuni River. The Orinoco and the Amazon basins are connected through the Brazo Casiquiare, while the inundated savannah of Rupununi allows intermittent connections between the Branco and the Esequibo Rivers (Lowe-McConnell, 1964). There is no fresh-water continuity between the Orinoco and the Cuyuni basins. The fresh-water fauna of the Venezuelan Guayana has been explored superficially, and only along the courses of the main rivers and the few roads now existing in the area. The fresh-water shrimps of the Orinoco River are practically unknown (Rodriguez, 1980, 1981) except for a record of Macrobrachium amazonicum (Heller, 1862) in the lower Orinoco and another record of M. brasiliense (Heller, 1862) from Villavicencio, Colombia (Holthuis, 1952). Euatya sculptilis Koelbel, 1884, later synonymized under Atya gabonensis Giebel, 1875, was described from the Orinoco River basin, but its presence there has never been confirmed, although recently Hobbs (1980) recorded this West African species from Brazil.
50 citations
TL;DR: Barnacles were unevenly distributed over the proximal, medial, and distal portions of the gills and in the crab Scyllla serrata densities of two Octolasmisspecies were highly correlated, whereas in Charybdis cruciata the correlation between two other species of barnacles was less pronounced.
Abstract: Early in 1981 marine Crustacea (Decapoda) indigenous to Singapore waters were examined for epizoic pedunculate barnacles of the genus Octolasmis (Gray, 1825). Twenty-seven of the 56 decapod species examined were hosts of up to 7 Octolasmis species each. The Octolasmisspecies observed included O. angulata, O. bullata, O. cor, O. lowei, O. neptuni, O. tridens, O. warwickii, and three unnamed species. Of the 10 Octolasmis species one (rarely two) was found externally on the body and appendages and nine species were found internally in the gill chambers. Host specificity varied, but most Octolasmis species occurred on several host species. With one exception, significantly more barnacles were found on the inner side than on the outer side of the host gills. Barnacles were unevenly distributed over the proximal, medial, and distal portions of the gills. Generally barnacle species had distinctive distribution patterns over the gills. In the crab Scyllla serrata densities of two Octolasmisspecies were highly correlated, whereas in Charybdis cruciata the correlation between two other species of barnacles was less pronounced.
49 citations
TL;DR: For most species, there was little evidence of reproductive seasonality since ovigerous females of Munida longipes, Munidopsis bairdii, and Eumunida picta were collected only in fall or winter; however, ovigerously females of munidopsis rostrata, Munida valida, and Munidas longipes were collectedonly inFall or winter.
Abstract: Twelve species of Galatheidae and one species of Chirostylidae numbering 6,928 individuals were retrieved from trawl collections made on the continental shelf, slope, and rise in the Middle Atlantic Bight. The most abundant species collected was Munida iris iris which constituted >90% of the total catch of galatheoidean anomurans. Three other species (Munidopsis rostrata, Munida valida, and Munida longipes) comprised > 1% of the total number of Galatheoidea. The bathymetric distribution of Munidopsis spp. was confined to depths >500 m, whereas all except two Munida spp. were collected from the continental shelf and upper slope. Munida spp. and Eumunida picta produced large numbers of small eggs, whereas eggs from Munidopsis spp. were large and few in number. Ovigerous females of all species examined, except Munida microphthalma and Eumunida picta, had larger carapace lengths than males and other females. For most species, there was little evidence of reproductive seasonality since ovigerous females were collected throughout the year; however, ovigerous females of Munida longipes, Munidopsis bairdii, and Eumunida picta were collected only in fall or winter. Parasites of Galatheoidea were mainly bopyrid isopods and rhizocephalan barnacles. The incidence of parasitism was low for all species examined.
47 citations
TL;DR: Collection of isopod crustaceans from a wide variety of intertidal marine habitats in Queensland, Australia, contained five new species and a new genus of eubranchiate sphaeromatids.
Abstract: Collections of isopod crustaceans from a wide variety of intertidal marine habitats in Queensland. Australia, contained five new species and a new genus of eubranchiate sphaeromatids. Descriptions are given for the different stages of their growth and some ecological considerations are discussed. The new genus is Paradella and the new species are: Paradella octaphymata, new genus, new species; Dynamenella liochroea, new species; D. ptychura, new species; D. trachydermata, new species; and Ischyromene polytyla, new species. Ischyromene Racovitza, Dynamenella Hansen, Cymodocella Pfeffer, and Dynamenopsis Baker are redefined and rediagnosed. The importance of founding species on descriptions of adult males is stressed, but this should be supplemented with descriptions of all other stages of the life cycle if possible. The form of the brood pouch of the ovigerous female and the form of the penes and appendix masculina of the mature male should be included as these characters are relatively consistent at the generic level.
TL;DR: It is predicted that measurable numbers of new snail shells are transferred daily to hermit crabs in habitats where gastropod frequently prey upon other gastropods.
Abstract: We predicted that measurable numbers of new snail shells are transferred daily to hermit crabs in habitats where gastropods frequently prey upon other gastropods. The rate of new shell acquisition by hermit crabs, Pagurus longicarpus, was monitored daily in northeastern Gulf of Mexico salt marshes where crown conchs, Melongena corona, prey heavily upon marsh periwinkles, Littorina irrorata. Periwinkle shells, marked while housing live snails, appeared on P. longicarpus at daily rates ranging from 1 to >20 for selected areas of approximately 60 m2 in three marshes. The maximum number (22.8) of new periwinkle shells appearing among P. longicarpus in the immediate area (300 m2) represented 16.5% of crabs present there each day.
TL;DR: The larval development of C. mccullochi is intermediate in type between the direct developments and the more prolonged indirect developments described previously for Caridina spp.
Abstract: The larval development of C. mccullochi is intermediate in type between the direct developments and the more prolonged indirect developments described previously for Caridina spp. Its discovery has allowed the identification of a complete sequence of progressively abbreviated larval developments within the genus. The larval development of C. mccullochi is described in detail and a number of generalisations are discussed concerning the selective nature of the changes associated with the progressive reduction of the larval phase in the genus.
TL;DR: During winter months on Seven and One-half Fathom Reef, reproduction is attenuated in populations of Synalpheus fritzmuelleri and S. apioceros, and much lower percentages of both populations carry normal eggs in winter months, and brood sizes appear to be smaller.
Abstract: During winter months on Seven and One-half Fathom Reef, reproduction is attenuated in populations of Synalpheus fritzmuelleri and S. apioceros. Some ovigerous specimens occur throughout the year, but much lower percentages of both populations carry normal eggs in winter months, and broods of these eggs appear to be smaller. A seemingly wasteful production of nonviable, minute, chalky eggs by S. apioceros during winter months and the absence of such eggs in S. fritzmuelleri under the same ambient conditions could relate to the more tropical restriction of the former species. On Seven and One-half Fathom Reef, S. apioceros is probably near the northernmost extreme at which it can successfully reproduce.
TL;DR: The reliance of G. lateralis upon adult behaviors to reduce risks during migration and spawning is compared with strategies of other land crabs which appear to rely more heavily upon larval adaptations.
Abstract: Females of the red land crab Gecarcinus lateralis (Freminville) must leave the physiological and physical protection of a terrestrial burrow to carry their developing egg masses to the surf and release the pelagic larvae. En route, both adults and eggs may encounter increased risks from predators, extremes of salinity (rain or concentrated tidepools), and wave impact. Several types of behavior by ovigerous females reduce these risks to both adult females and larvae during migration and spawning. Females migrate directly toward the shore, reducing the time required to reach the sea. They spawn synchronously. Ovigerous females actively release eggs only when the eggs are ripe, precluding premature release, but will do so in water of any salinity, whether still or agitated. Physiological adaptations of larvae would contribute little to their survival were eggs released in extreme salinities; the range of tolerance is only 50-125% sea water. The spawning females avoid standing water of any salinity, thereby preventing release of larvae in dilute or concentrated tidepools, or those without connection with the sea. Females begin migration to the nearshore zone before egg-releasing behavior develops, hence are unlikely to release eggs prematurely if inundated by rain. Spawning females approach the surf hesitantly, minimizing the risk of being swept to sea. The reliance of G. lateralis upon adult behaviors to reduce risks during migration and spawning is compared with strategies of other land crabs which appear to rely more heavily upon larval adaptations.
TL;DR: Several aspects of an adult C. antennarius population are document including: 1) seasonal abundance, 2) sex ratio, 3) size composition, 4) molting and spawning periods, 5) individual growth rates, and 6) migratory behavior.
Abstract: Bimonthly crab trapping and tagging efforts off the central coast of California from August 1976 to April 1981 yielded data on over 9,000 adult Cancer antennarius, the northeastern Pacific rock crab. Female crabs were most abundant during autumn, the period of warmest water temperatures along central California, but males exhibited no clearly defined seasonal abundance trends. Ovigerous females were prevalent during winter, resulting in the subsequent dispersal of pelagic larvae during spring and early summer. Rock crabs attain sexual maturity about 2 years after settlement, at a size of 60-80 mm carapace width. Adult crab growth averages 16.7% in carapace width and 57.7% in body weight after a single molt, with intermolt periods of up to 16 months duration. Maximum size may exceed 150 mm in carapace width and 900 g in body weight after 5 or 6 years making C. antennarius a desirable sport and commercial fishery species. Tag returns averaged 6.3% while tag loss, as detected by a scar on the epimeral suture of recaptured crabs, was 14.4%. Nearly half of all recaptured crabs were recovered at their original release site after 2-18 months, although migratory distances of 7 km were recorded for several individuals. The northeastern Pacific rock crab Cancer antennarius Stimpson is an edible crab common along the central Californian coast of North America, and ranges from Oregon to Baja California (Garth and Abbott, 1980). Three sympatric species of Cancer, all commonly referred to as "rock crab," inhabit the central Californian coast: C. antennarius (rock crab), C. productus Randall (red crab), and C. anthonyi Rathbun (yellow crab). Of these, C. antennarius is the most abundant in shallow waters of the outer rocky coast. In central and southern California these three species have supported a small sport and commercial fishery for over thirty years (Frey, 1971). Despite its common occurrence and commercial importance, the Pacific rock crab has received little attention in the scientific literature beyond descriptions of larval development (Mir, 1961; Roesajadi, 1976), laboratory behavior (Krekorian et al., 1974), molt cycle dynamics (Spaziani et al., 1981), and brief accounts of its general biology (Schmitt, 1921; Ricketts et al., 1968; Garth and Abbott, 1980). The objective of the present study was to document several aspects of an adult C. antennarius population including: 1) seasonal abundance, 2) sex ratio, 3) size composition, 4) molting and spawning periods, 5) individual growth rates, and 6) migratory behavior.
TL;DR: The two species are an exception to the right-left equality of handedness previously thought to prevail for the genus, and recently published studies provide possible clues to the mechanism for the determination of right-handedness and its functional significance.
Abstract: Right-handedness of the major cheliped was found in 97.3% of 2,784 male specimens of U. vocans from collections of the National Museum of Natural History (U.S. National Museum) and the 1979 R/V ALPHA HELIX expeditions to the western Pacific. A comparable figure of 96.8% right-handedness was obtained for 281 specimens of the rarer U. tetragonon. Since the collections span the known geographical ranges of both species, it would appear that a strong bias for right-handedness is a universal trait for each. The two species are thus an exception to the right-left equality of handedness previously thought to prevail for the genus. Recently published studies provide possible clues to the mechanism for the determination of right-handedness and its functional significance.
TL;DR: The cuticular structures described in this study are used to scrape and brush the body during grooming movements, presumably enabling these crustaceans to exploit better their environment.
Abstract: Six talitroidean amphipod species from terrestrial, semiterrestrial, fresh-water, and marine habitats were examined with scanning electron microscopy. A number of specialized and ornate grooming organs are described in which cuticular scales and setae have been modified into bristles, fans, combs, and brushes. Terrestrial, semiterrestrial, and aquatic groups possess grooming modifications quite distinct from each other, while individual species, within a single habitat group, differ much less. The structure and function of several nongrooming specializations is also discussed. Although sexual dimorphism of arthropod grooming structures is rare, such dimorphism is present in the Amphipoda. This dimorphism stems from the use of the major grooming appendages as precopulatory organs in the male. The cuticular structures described in this study are used to scrape and brush the body during grooming movements, presumably enabling these crustaceans to exploit better their environment.
TL;DR: In this paper, the authors discuss the nomenclature used to designate groups of sphaeromatid genera and propose new properly formed names to replace the previously incorrectly formed subgroups of Hansen and others that have been proposed over the years.
Abstract: Nomenclature used to designate groups of sphaeromatid genera is discussed. New, properly formed, names are proposed to replace the previously incorrectly formed subgroups of Hansen and others that have been proposed over the years since Hansen. A diagnosis and list of the genera with authors is given for each subfamily. A key to the subfamilies is provided.
TL;DR: The morphogenetic interrelationships of the observations are discussed and it is suggested that P. bithynis is more advanced phylogenetically than either P. pandalicola or P. floridensis.
Abstract: Larvae of Probopyrus pandalicola, P. floridensis, and P. bithynis were raised experimentally in the laboratory. Development times of larvae (epicaridium to cryptoniscus) and intermediate host selection were the same for all parasite species. We used SEM and LM to obtain both morphological and morphometric data on first and final stage larvae from each species. While P. bithynis larvae are distinct morphologically, P. floridensis and P. pandalicola larvae are similar to one another, but often differ significantly in several body measurements. Furthermore, cryptonisci of P. floridensis and P. pandalicola differ in regard to host specificity, pigmentation, and swimming speed. The authors conclude that P. pandalicola, P. bithynis, and P. floridensis should retain separate species status. Finally, the morphogenetic interrelationships of our observations are discussed and we suggest that P. bithynis is more advanced phylogenetically than either P. pandalicola or P. floridensis.
TL;DR: Carapace length was found to be a better measurement than total length because no shrinkage occurred when exposed to preservatives nor was it susceptible to damage.
Abstract: Length to weight and other morphometric relationships were examined and the effects of preservatives on Meganyctiphanes norvegica and Thysanoessa inermis (Euphausiacea) from the Bay of Fundy were described. Weight increased exponentially with length, showing no significant difference between sexes. The relationships between two different total length measurements and carapace length are given so that studies from other areas using any of these three measurements can be compared. The change in slope of the line for the carapace to total length relationship for 0 and 1 year class animals revealed a change in body allometry, i.e., abdominal growth was reduced in the second year. A series of 14 weight change relationships from fresh to formalin through alcohol to dry weight demonstrated significant weight loss and change in total length depending on preservative or combination of preservatives used. Carapace length was found to be a better measurement than total length because no shrinkage occurred when exposed to preservatives nor was it susceptible to damage. A biochemical analysis of a sample of M. norvegica taken in August yielded a 79% water content, 56.0% protein, 13.1% lipid, and 15.8% ash, the last three values as a percentage of dry weight.
TL;DR: Thamnocephalus venezuelensis, new species, is described from specimens collected from an ephemeral pond located in Zulia, Venezuela and an additional collection is reported from Falcon, Venezuela, which represent the first known occurrence of Tham nocephalus in South America.
Abstract: Thamnocephalus venezuelensis, new species, is described from specimens collected from an ephemeral pond located in Zulia, Venezuela (11°20ʹN, 72°05ʹW). An additional collection is reported from Falcon, Venezuela (11°25ʹN, 69°40'W). These two populations represent the first known occurrence of Thamnocephalus in South America. The genus was previously thought to be confined to North America.
TL;DR: Morphological features shared among both the zoeal and megalopal stages of the various mithracine genera are compared, and phylogenetic relationships within Microphrys, Mithrax, and Macrocoeloma are proposed.
Abstract: The complete larval development, consisting of two zoeal stages and a megalopa, and the first crab stage is described for the shallow-water western Atlantic spider crab Microphrys bicornutus. Data from laboratory cultures indicate that the species can complete its planktonic development in less than a week, and is able to attain first crab stage in as few as 10 days. The zoeal stages of M. bicornutus show a great many similarities to known zoeae in other genera within the subfamily Mithracinae, including species of the American genus Mithrax, and to Mucrocoeloma, and to a lesser extent the Indo-West Pacific genera Tiarinia and Micippa. Morphological features shared among both the zoeal and megalopal stages of the various mithracine genera are compared, and phylogenetic relationships within Microphrys, Mithrax, and Macrocoeloma are proposed.
TL;DR: Analysis of 340 published descriptions of larval development in the Anomura and Brachyura reveals that the maxillary scaphognathite of the first zoeal stage can be classified into one of eight types.
Abstract: Analysis of 340 published descriptions of larval development in the Anomura and Brachyura reveals that the maxillary scaphognathite of the first zoeal stage can be classified into one of eight types. In addition, there are five sequences by which the diverse zoeal scaphognathites develop into the typical postlarval form. These features appear to be valuable taxonomic characters and provide relevant larval evidence concerning the lower limits of the Brachyura and affinities within the Anomura.
TL;DR: The complete larval development of Gecarcinus lateralis lateralis (Freminville, 1835), a gecarcinid land crab from Bermuda, is described and illustrated based on larvae reared in the laboratory.
Abstract: The complete larval development of Gecarcinus lateralis lateralis (Freminville, 1835), a gecarcinid land crab from Bermuda, is described and illustrated based on larvae reared in the laboratory. The species passes through six (possibly five) zoeal stages and one megalopal stage. The development through six zoeal stages to the young crab stage takes at least 29 days. Morphological characters of G. I. lateralis larvae are compared with gecarcinid species of which the complete larval development is known, i.e., Cardisoma guanhumi and C. carnifex.
TL;DR: New species of cardinalfish described from the gill chambers of the whitestar cardinalfish Apogon lachneri Bohlke from Puerto Rico; and the dusky cardinalfish Phaeoptyx pigmentaria and the freckled cardinalfish P. conklini from the Bahamas.
Abstract: Mothocyabohlkeorum, new species, is described from the gill chambers of the whitestar cardinalfish Apogon lachneri Bohlke from Puerto Rico; and the dusky cardinalfish Phaeoptyx pigmentaria (Poey) and the freckled cardinalfish P. conklini (Silvester) from the Bahamas. It may be distinguished from Mothocya nana (Schioedte and Meinert) by the shape of the frons and telson; and by having a cephalon which is slightly instead of deeply immersed in pereonite 1. Larger female M. bohlkeorum occur on the larger hosts. Female isopods may undergo vegetative growth stages between reproductive brood stages. Male and female isopods occur in opposing gill chambers of a host. This duplex male-female association may explain how relatively large cymothoid isopods colonize small host species.
TL;DR: The terrestrial crabs Gecarcinus ruricola and G. lateralis are sympatrically distributed in many areas of the Caribbean and shows an increase in mean size from eastern to western localities, but growth in both species is allometric.
Abstract: The terrestrial crabs Gecarcinus ruricola and G. lateralis are sympatrically distributed in many areas of the Caribbean. Biometric analyses were conducted using four carapace dimensions and branchial volumes for both species throughout the Caribbean. Mean size of adult G. ruricola does not differ significantly among areas of the Caribbean. G. lateralis shows an increase in mean size from eastern to western localities. The carapace of G. ruricola lateral to the orbits is proportionally larger than the corresponding area of G. lateralis, but growth in both species is allometric. Thus, one should employ caution in using carapace ratios for taxonomic discrimination between the species. The branchial chambers of both G. lateralis and G. ruricola increase in size approximately as the cube of the carapace length. An expansion in the lateral carapace dimension of G. ruricola provides a small increase in branchial volume and a relatively larger increase in surface area which presumably facilitates gaseous exchange with the atmosphere. G. lateralis occurs most frequently in the presence of easily burrowed sandy substrate with at least moderate protection by vegetation. G. ruricola occurs almost exclusively under a forest canopy where it seeks protection in crevices, holes, or other retreats with minimal need for burrowing.
TL;DR: The family Corallanidae is defined, with the monogeneric family Excorallanids being placed in synonymy and the genera Austroargathona and Corilana are of doubtful status.
Abstract: The family Corallanidae is defined, with the monogeneric family Excorallanidae being placed in synonymy. The family is now regarded as containing the following genera: Alcirona, Argathona, Austroargathona, Excorallana, Corallana, Lanocira, Tachaea, and Tridentella.The genera Austroargathona and Corilana are of doubtful status.
TL;DR: Aegla bahamondei, new species (Crustacea, Anomura, Aeglidae) is described from the Tucapel River on the western slope of Cordillera de Nahuelbuta, Chile, and closely resembles A. rostrata Jara from preandean lakes of the Valdivia and Tolten river basins.
Abstract: Aegla bahamondei, new species (Crustacea, Anomura, Aeglidae) is described from the Tucapel River on the western slope of Cordillera de Nahuelbuta, Chile. Morphologically it closely resembles A. rostrata Jara from preandean lakes of the Valdivia and Tolten river basins. A. bahamondei differs from A. rostrata in its acute median tubercle on the fourth thoracic sternum, less prominent overall spinulation, and nonstilettolike rostrum. The morphological similarity between A. bahamondei and A. rostrata is interpreted as indication of recent common ancestry. It is hypothesized that A. bahamondei represents the plesiomorphic and A. rostrata the apomorphic species. The Chilean coastal mountain range of Nahuelbuta, stretching between 37? and 39?, is a region of faunistic individuality compared with the remaining southern Chilean territory. This view is supported by the existence of at least two genera of Plecoptera (Insecta) and one species of Anura restricted to this region (Illies, 1969; Formas, 1979); these authors presume that the Cordillera de Nahuelbuta served as a refuge for the preglacial Tertiary fauna. Arenas (1976) has suggested that in postglacial times some freshwater fishes and amphibians could have extended their geographic range from this coastal refuge to the Andes. Four species of crayfishes (Parastacidae) and three species of Aeglidae (Bahamonde and L6pez, 1963; Jara, 1977) are known from freshwaters in the Chilean region between Concepci6n and Valdivia provinces. However, none of the Aegla species have been recorded from the Cordillera de Nahuelbuta itself or from its immediate surroundings. This paper describes as a new species a form of Aegla Leach found in a small river on the western slope of the Cordillera de Nahuelbuta.
TL;DR: The combination of a hoodlike rostrum with a presumed glandular apex, and low morphological diversification of peraeopods 5-7 requires the erection of a new family, the Cheidae.
Abstract: Cheus annae, new genus, new species, is described and figured Comparisons with the Phoxocephalidae, Urothoidae, Platyischnopidae, Haustoriidae, and Pontoporeiidae show many characters in common, particularly with the first three families The combination of a hoodlike rostrum with a presumed glandular apex, and low morphological diversification of peraeopods 5-7 requires the erection of a new family, the Cheidae