Liberta E. Scotto

Studies on decapod crustacea from theIndian River Region of Florida: XI. Community composition, structure, biomass andspecies-areal relationships of seagrass and drift algae-associated macrocrustaceans

A 1-year study, using six 10 m2 drop nets at monthly stations, was conducted on the seagrass and drift algae-associated macrocrustaceans (primarily Decapoda) in the Indian River lagoon on the central eastern Florida coast. The macrocrustacean community consisted of 38 species, in 28 genera and 17 families, the majority of which were caridean (grass) shrimp and brachyuran crabs. Two caridean shrimp, a pagurid crab, and a penaeid shrimp were numerically dominant species which, together with 10 less numerous species, were considered to be characteristic representatives of the macrocrustacean community. Both a species-area and individuals-area relationship were demonstrated using a combinatorial statistical method, and a modification of the Fisher species-individuals relationship. The community as a whole responded in numbers of individuals, and in total crustacean biomass, to increases in seagrass and drift algae (as plant biomass g−1 m−2). Macrocrustacean community diversity appeared to be regulated by above-ground plant abundance, and is thus a function of habitat complexity. The consistency of decapod species composition indicated that the community is both predictable and resilient, with resultant stability due, in some measure, to habitat diversity produced by the periodic trimonthly increases in drift algae abundances. Competitive exclusion may be more important than predation on this seagrass bed in regulating the within-habitat diversity of the macrocrustacean community.

Microphrys Bicornutus (Latreille, 1825) : The Complete Larval Development Under Laboratory Conditions with Notes on Other Mithracine Larvae (Decapoda: Brachyura: Majidae)

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.

Studies On Decapod Crustacea From the Indian River Region of Florida. Xiv. a Method for Rapid Preparation of Brachyuran Larvae for Scanning Electron Microscopy

Introduction. ? Scanning electron microscopy (SEM) has become an important tool in the elucidation of both gross morphology and fine structures in many groups of crustaceans (e.g. Copepoda, Grice & Lawson, 1971; Ostracoda, Sandberg, 1970; Cirripedia, Rainbow & Walker, 1976; Euphausiacea, Guglielmo & Costanzo, 1977). Although adult decapod crustaceans have been studied in some detail (e.g. Abele, 1971; Mauchline et al., 1977; Hindley & Alexander, 1978; Williams, 1978), scanning microscopy of larvae of this group has received only slight atten tion (Laughlin & Neff, 1976; Bellon-Humbert et al., 1978). The number of SEM fixation procedures has been as varied as the authors who proposed them and the composition of the specimens examined. For example, adult decapod structures such as xanthid crab gonopods (Abele, 1971), integu mental sensilla of pelagic shrimp (Mauchline et al., 1977), hermit crab spines (McLaughlin & Lane, 1975) and chelate pereiopods of penaeid shrimp (Hindley & Alexander, 1978) have been prepared for SEM by dehydration through an alcohol series before airor freeze-drying. Fujino (1975), studied the dactylus of the ambulatory pereiopods of a pontoniine shrimp using an alternate fixation method which involved soaking the appendages in a gluteraldehyde, and then an osmium tetroxide solution. Other fixation procedures involving the scanning of adult decapods can be found in Bauer (1975, 1977) and Felgenhauer & Schr?m (in press). Scanning of decapod larvae, on the other hand, has been neglected. The sparse literature includes the studies of Laughlin & Neff (1976) on the sensory structures of the zoeae of Rhithropanopeus harrisii (Gould), and Bellon-Humbert et al. (1978) on the development and location of sensory and neurosecretory sites in larval and postlarval Palaemon serratus (Pennant). The latter authors provide to date the only published methodology for preparation of decapod larvae for SEM. Their procedure consisted of washing the larvae in distilled water and in am moniacal water (0.1%), fixing in a 100% ethanol-chloroform mixture (2:1) for a week, and rinsing in 100% ethanol and in n-butanol (3 changes each). During a laboratory study on the larval development of the brachyuran crab, Menippe nodijrons Stimpson (see Scotto, in press), several zoeal stages were prepared for SEM by applying a new methodology. This quick and simple tech nique, which requires a minimal number of chemical reagents, is described below. Materials and methods. ? Representative samples of each zoeal stage of M.

Studies on Decapod Crustacea from the Indian River Region of Florida Xxvii. Phimochirus Holthuisi (Provenzano, 1961) (Anomura: Paguridae): the Complete Larval Development Under Laboratory Conditions, and the Systematic Relationships of its Larvae

In a recent revision of several pagurid genera, McLaughlin (1981a, b) noted that at least 44 species had been assigned at one time or another to the genus Pylopagurus A. Milne Edwards and Bouvier, 1891. In splitting the genus Pylopagurus into 10 new genera, McLaughlin restricted only five species to Pylopagurus sensu stricto, placing nine other species in her new genus Phimochirus. Adults of Phimochirus are distinguished from other closely related genera in the pylopagurid group primarily by chelipedal and uropodal characters (see McLaughlin, 1981a). The larval development either within Phimochirus, or within Pylopagurus sensu lato, is completely unknown, although species in both taxa are not uncommon in the western and eastern Atlantic and eastern Pacific Oceans. Consequently, a comparison of larval characters within and across generic boundaries might provide additional data supporting or negating the recent generic revisions. In this paper we report on the complete larval development of Phimochirus holthuisi (Provenzano, 1961), a wide-ranging species found in littoral and continental shelf waters to a depth of 252 m, from North Carolina to Texas, the Caribbean Sea and Colombia to Brazil (McLaughlin, 1981b). We compare possibly important characters exhibited by these larvae with those known in larvae from other related pagurid species. MATERIALS AND METHODS

Studies on Decapod Crustacea from the Indian River Region of Florida, XXV. Carapacial and Abdominal Allometry in Five Species of Subtropical Parthenopid Crabs (Brachyura Parthenopidae)

[La croissance relative de caracteres cephalothoraciques et abdominaux choisis a ete examinee chez cinq especes de crabes parthenopides recueillis sur le plateau continental, a lest et a louest de la Floride. En general la largeur de la carapace presentait une allometrie positive par rapport a sa longueur dans des series de mâles, de femelles, de femelles ovigeres et de juveniles, ranges par taille, avec une expansion de la carapace plus prononcee chez les femelles, ovigeres ou non. En vue dessayer de determiner la taille a la mue de puberte, les rapports bivaries de la longueur du gonopode mâle ou de la largeur du cinquieme somite abdominal des femelles a la largeur de la carapace ont ete calcules et schematises sous la forme de regressions log-log. La divergence dans les lignes de regression a permis lextrapolation dune phase de mue puberale, laquelle chez la plupart des especes se produit entre des limites restreintes, de 3 mm environ., La croissance relative de caracteres cephalothoraciques et abdominaux choisis a ete examinee chez cinq especes de crabes parthenopides recueillis sur le plateau continental, a lest et a louest de la Floride. En general la largeur de la carapace presentait une allometrie positive par rapport a sa longueur dans des series de mâles, de femelles, de femelles ovigeres et de juveniles, ranges par taille, avec une expansion de la carapace plus prononcee chez les femelles, ovigeres ou non. En vue dessayer de determiner la taille a la mue de puberte, les rapports bivaries de la longueur du gonopode mâle ou de la largeur du cinquieme somite abdominal des femelles a la largeur de la carapace ont ete calcules et schematises sous la forme de regressions log-log. La divergence dans les lignes de regression a permis lextrapolation dune phase de mue puberale, laquelle chez la plupart des especes se produit entre des limites restreintes, de 3 mm environ.]

STUDIES ON DECAPOD CRUSTACEA FROM THE INDIAN RIVER REGION OF FLORIDA. XXIII. THE LABORATORY CULTURED ZOEAL STAGES OF THE CORAL GALL-FORMING CRAB TROGLOCARCINUS CORALLICOLA VERRILL, 1908 (BRACHYURA: HAPALOCARCINIDAE) AND ITS FAMILIAL POSITION

The first 5 zoeal stages of the brachyuran, coral-inhabiting, gall-forming crab Troglocarcinus corallicola Verrill, 1908, are described and illustrated. Based on the sequential appearance of morphological characters, this species passes through at least 5, and perhaps 6 or 7 larval stages before metamorphosing to megalopa. The zoeae can be easily recognized in the plankton by a combination of lateral aliform expansions on the fourth, and a distinct dorsal caplike process on the second abdominal somite. The number of abdominal somites (5) remains constant throughout the first 5 (and probably subsequent) zoeal stages. Evidence from larval morphology supports the contention based on adult characters, that the Hapalocarcinidae are closely related to the Pinnotheridae, as well as having close affinities to the Hymenosomatidae and Leucosiidae. The family Hapalocarcinidae is a widespread group of approximately 27 species in at least 8 genera (Fize and Serene, 1957; Takeda and Tamura, 1979). The major distribution is throughout the Pacific and Indian Oceans, with only 3 species presently recorded from the Atlantic Ocean (2 from the western Atlantic and one from the eastern Atlantic). The family is unique in that the members symbiotically associate with scleractinian corals by forming galls, dens, or depressions within the substratum of the living corallum. Previous studies have been primarily taxonomic in nature, but the group is so taxonomically confusing that its phylogenetic position within the brachyuran Decapoda has not been established with certainty. Within the family, first zoeal larvae have been briefly described and inadequately illustrated for only 3 species (Potts, 1915; Edmondson, 1933; Fize, 1956; Al-Kholy, 1963; as reviewed in Castro, 1976), so that the larval development within the family can be considered practically unknown. Of the 2 species known from the western Atlantic Ocean, Troglocarcinus corallicola is the most widespread, being recorded from Bermuda (the type-locality of Verrill, 1908), Straits of Florida, northeastern Gulf of Mexico, and Dominica, British West Indies (Rathbun, 1937; Shaw and Hopkins, 1977). The species is a known symbiont of madreporarian hermatypic corals, in which it forms lunate galls or dens. However, our collections made off the central eastern Florida coast showed the species to be an associate of the Ivory Tree Coral Oculina varicosa Lesueur, 1820, as well. Among specimens obtained were several ovigerous females. These offered an opportunity to study the larval development of the species, and perhaps clarify systematic relationships within the family. Accordingly, this paper reports on the first 5 larval stages of Troglocarcinus corallicola, and (as far as previously published data allow) compares morphological characters of the zoeae with those noted for the Pacific species Hapalocarcinus marsupialis Stimpson, 1859 (Potts, 1915; Al-Kholy, 1963) and Cryptochirus minutus Edmondson, 1933 [=C. coralliodytes Heller, 1861, fide Utinomi, 1944].

EARLY ZOEAL STAGES OF THE SEMITERRESTRIAL SHRIMP MERGUIA RHIZOPHORAE (RATHBUN, 1900) CULTURED UNDER LABORATORY CONDITIONS (DECAPODA NATANTIA, HIPPOLYTIDAE) WITH A DISCUSSION OF CHARACTERS IN THE LARVAL GENUS ERETMOCARIS

Les larves de Merguia rhizophorae elevees en laboratoire presentent beaucoup des caracteristiques typiques des larves attribuables a la famille des Hippolytidae et au genre larvaire composite Eretmocaris. Les larves ont un flagelle antennaire fortement allonge, a partir du second stade, ce qui semble les distinguer des autres Eretmocaris. On ne peut comparer ces stades larvaires avec ceux des autres Carides que de facon approximative, par manque de connaissances sur la plupart des larves de la famille. Nous suggerons que le genre larvaire Eretmocaris soit conserve jusqua ce que les caracteristiques larvaires des especes soient mieux connues.

Early Larval Stages of the Indo-Pacific Coral Gall-Forming Crab Hapalocarcinus Marsupialis Stimpson, 1859 (Brachyura, Hapalocarcinidae) Cultured in the Laboratory

Die beiden ersten Larvenstadien der gallbildenden Art Hapalocarcinus marsupialis Stimpson aus dem Pazifik wurden unter laborbedingungen aufgezogen. Die Larven werden abgebildet und beschrieben und mit den Larven von Troglocarcinus corallicola Verrill aus dem Atlantik verglichen. Die Larven beider Arten haben wenigstens 10 Merkmale gemein und unterscheiden sich nur in den drei folgenden: Verhaltnis der Antennaldornen, Borstenformel der Endopodite, relative Grosse der medioventralen Tuberkel am 5. Abdominalsegment. Aufgrund der Larvalmerkmale ist die Gattung Hapalocarcinus in der Nahe der Familien Pinnotheridae, Hymenosomatidae und Leucosiidae zu stellen.