Abdominal Width Research Articles

Morphometric characterization of thalassohaline Artemia franciscana populations from the Colombian Caribbean

AbstractAim To establish possible interpopulation relationships among Colombian Artemia franciscana (Crustacea, Anostraca) populations.Location Colombian Caribbean coast (Manaure, Galerazamba, Salina Cero and Tayrona) and a similar thalassohaline reference population from San Francisco Bay (SFB‐USA).Methods Morphometric characters of male and female cultured individuals of A. franciscana were measured. The populations were grouped according to: (1) population type (populations grouped according to two broad regions of origin: North America and the Caribbean coast), and (2) specific geographical origin (populations selected according to five specific local origins: Manaure, Galerazamba, Salina Cero, Tayrona and SFB) and evaluated using forward stepwise discriminant analysis (SPSS, Ver. 10).Results Optimal discriminant variables for males grouped by the type of population were left setae and antenna length, and for females they were abdominal length and antenna length. However, for males grouped by their specific geographical origin, the optimal variables were furca length, left setae, antenna length, eye separation, abdominal width and abdominal length, and for the females, they were furca length, abdominal length, left setae and eye separation. Male and female Colombian Caribbean populations were separated from the North American populations. However, our results show that the classification based on male characters provides better group membership than females.Main conclusions Male morphometric characters separated the type of population groups more clearly than the female characters, because all Colombian populations were correctly positioned in the Caribbean coast region and the SFB population in the North American region, with no overlapping between the two types, as was the case for the female individuals. Likewise, male individuals correctly position the Salina Cero population to its neighbouring Galerazamba population and to the other Colombian populations. In contrast, female individuals from Salina Cero did not cluster with the other Colombian coast populations (Galerazamba, Tayrona and Manaure) or with the SFB population.

Development of external sexual characters in the deep-sea sponge-associated shrimp Spongicola japonica Kubo (Crustacea: Decapoda: Spongicolidae)

Development of external sexual characters in the deep-sea sponge-associated shrimp, Spongicola japonica Kubo is investigated. Sexual dimorphism is observed in the gonopore, pereopod 3, abdominal width, pleuron and pleopods, and the size difference between paired shrimps is apparent. The external appearance of the gonopore is the first evidence of sexual dimorphism, opening on the coxa of pereopod 3 of females, while on the coxa of pereopod 5 of males. In females a slower growth rate for the pereopod 3 chela length and a positive growth rate for the abdominal width is recognized when both sexes are compared. The morphological changes in abdominal appendages during the formative period of the brooding chamber are illustrated.

RUNT-DEFORMITY SYNDROME IN CULTURED GIANT TIGER PRAWN PENAEUS MONODON

Abstract A total of 24 morphological abnormalities associated with the Runt-Deformity Syndrome (RDS) is reported for the first time in 17- to 18-mo old F3 generation Penaeus monodon (>40 mm CL) belonging to three breeding families. Although diagnosed as positive for the infectious hypodermal and hematopoietic necrosis virus (IHHNV), the shrimp appeared normal at 9 to 10 mo when they were procured from a commercial facility in Antique, central Philippines, in September 1996. The abnormalities affected either specific shrimp organs and appendages (e.g., rostrum, antennae, uropods) or the whole body (e.g., shell color and hardness). A two-way analysis of variance was used to evaluate differences in the morphometric characters rostral length (RL), carapace length (CL), abdominal length (AL), body length (BL), total length (TL), carapace width (CW), 1st abdominal segment width (AS1W), and body weight (BW) and the morphometric ratios RL:CL, CL:AL, and CW:AS1W by sex and stock (3 families and wild controls). Fem...

Proportional growth and maturation in Penaeus indicus

A least squares estimation of inflected linear regression is used to interpret the relationships between carapace length (CL) and total length, abdominal length and abdominal width respectively, in Penaeus indicus and Metapenaeus monoceros. In both species well-defined inflection points with significant differences between slopes are evident in each of these relationships. In P. indicus males, changes in proportional growth are evident at 27.5–29.3mm CL. In females two inflection points are evident, one at 28.8–31.0mm CL and another at 39.7mm CL. Similarly, in M. monoceros, males show a proportional growth change at around 22mm CL and females at 27mm and 34mm respectively. These changes in P. indicus occur at the approximate sizes at which mating maturity and ovarian maturity are attained, suggesting that they may be linked.

Morphometry, Sexual Dimorphism and Size At Maturity of the White-Clawed Crayfish Austropotamobius Pallipes Pallipes (Lereboullet) From a Wild French Population At Deux-Sèvres (Decapoda, Astacidea)

This paper describes patterns of sex and size dimorphism and allometric growth in a French population of the native crayfish species, Austropotamobius pallipes pallipes. The threatened status of this species shows the necessity to establish a suitable management to protect it. An efficient management requires an increase in our knowledge about existing populations. By using allometric relationships, we characterized the size at the onset of sexual maturity in both sexes and evaluated sexual dimorphism in this population. The size at the onset of sexual maturity appeared to be different in both sexes (20.1 mm POL in males and 18.17 mm POL in females). The sexual dimorphism, shown by the variables of claw length and abdominal width, was not closely related to the puberal moult. The growth rates of this population were very different from those shown by other European populations. Discriminant analysis was performed on the data, but it did not separate the juveniles of both sexes. This study provides fundamental results concerning the relative growth of A. pallipes which could be used to compare several French populations in the future.

FECUNDITY AND RELATIVE GROWTH OF THE CRAB PLATYXANTHUS PATAGONICUS (BRACHYURA: PLATYXANTHIDAE) IN PATAGONIA, ARGENTINA

A total of 1.046 individual s of the crab Platyxanthus patagonicus were collected in the fishery area near Puerto Rawson, Chubut, Argentina. Fecundity and relative growth were determined using carapace length (CL) as the reference dimension. Ovigerous females (42.7-72.0-mm CL) were sampled in winter, spring, and early summer. Mean (±SE) fecundity (97,900 ± 37,800 eggs) was positively related cr' = 0.71) to CL. For all the relationships in which relative growth was explored, the FORTRAN program Mature II computer technique (Somerton, 1983) was used to estimate the size at sexual maturity. For both sexes, MATURE II did not detect (P > 0.05) any abrupt change in the rate of relative growth of carapace width (CW) versus CL. The rate of growth of CW was negatively (b 1) allometrie for males. Instead, the rate of growth of the major propodus length (PL) was isornetric for females and positively allometric for males. For males, possible size al sexual maturity oecurs at -44-rnm CL, sinee the Mature method detected an abrupt change in the rate of relative growth of PL at this size. Relative growth of the sixth abdominal segment width (A W) was positively allometrie for females and isometric for males. For fernales, a ehange in the rate of relative growth of AW and sixth abdominal segment length (AL) was observed at -50-rnrn CL. This result, in conjunction with the faet that the minimum size found for an ovigerous female was 42.7-rnm CL, suggests that in females, sexual maturity oeeurs al 40-50-rnm CL. In males, relative growth of AL versus CL was positively allometrie up ro a size of 44-mm CL; above this size relative growth was isometric.

POTAMONAUTES DENTATUS, NEW SPECIES, A FRESH-WATER CRAB (BRACHYURA: POTAMOIDEA: POTAMONAUTIDAE) FROM KWAZULU-NATAL, SOUTH AFRICA

ABSTRACT Potamonautes dentatus, new species, a fresh-water crab from the Mgeni River, KwaZulu-Natal, South Africa, is characterized by strongly denticulate anterolateral margins and the presence of a notch in the postfrontal crest posterior to the exorbital tooth. The new species is compared to other potamonautid species occurring in the region. Of the 12 morphometric relationships examined, 9 dimensions exhibited allometric growth: wet weight, anterior and posterior width of the carapace, body depth, and abdominal width in both sexes, length (in males) and width of the merus of pereiopod 2 for both sexes combined, and major cheliped propodus length and height in both sexes. Sexual dimorphism was demonstrated for wet weight, abdominal width, major cheliped propodus length and height, and length of the merus of pereiopod 2.

Relative Growth of the Speckled Swimming Crab Arenaeus Cribrarius (Lamarck, 1818) (Brachyura, Portunidae), Near Ubatuba, State of São Paulo, Brazil

AbstractArenaeus cribrarius is a mainly tropical crab that occurs in the Western Atlantic Ocean, Brazil being its type-locality. The species ranges from Vineyard Sound, Massachusetts, USA to La Paloma, Uruguay. Information about this species is scarce. The relative growth ofA. cribrarius was analyzed, based on some morphometric relations, where the carapace width, excluding lateral spines (CW), was used as an independent variable. A total of 403 specimens (189 males and 214 females), was collected in Ubatuba, State of São Paulo, Brazil, with otter-trawls. The animals were sexed and sorted to maturation phase (juvenile or adult). Some measurements were made: carapace (length and width excluding lateral spines), abdomen (greatest width of the fifth somite in females and the sixth in males) and major chela (greatest length, width and height, dactylus length). This study was made by the application of the power function (y=a.xb) which was fitted to the data and the pattern of growth established for each parameter by the "b"-value (constant of allometry), as positive allomctry (b>1), negative allometry (b<1) or isometry (b=1). The morphometric relations of the carapace showed a tendency to isometry. In females, the abdominal width grew in positive allometry, higher in juveniles (b= 1.33) than in adults (b=1.18). In this case, an overlap and discontinuity was noticed between the phases over a carapace width range of 55 to 70 mm, where the puberty molt occurs. The majority of relationships showed that the major chela of the males grew in positive allometry, however, the greatest allometric difference between the phases was observed towards the propodus length with 1.09 as juvenile and 1.26 as adult "b"values. In the males, this variable showed an inflection between the CW range of 45 to 55 mm, where the transition to the maturation phase occurs. The relative growth of this species is similar to those of previously studied species. This indicates, that the propodus length and the abdominal width are the morphometric variables most appropriate to estimate the size at the beginning of the sexual maturity for males and females of this species, respectively.

飼育下における初中期シマイセエピフィロゾーマの成長と形態

Early and middle larval development of P. penicillatus reared in the laboratory for 160 days was examined. Although no puerulus was obtained, the larval development during the experiment was morphologically divided into seven stages. Average molting intervals were around six days for instars I-III and ten days after instar V. In most cases, one pair of setae was regularly added on the exopod of the 3rd maxilliped after instar II and those on the exopod of the 1st and the 2nd pereopods after instar V. Growth in body length and other body parts was indicated as an exponential curve. The growth patterns of the antennular and the antennal length and the abdominal width were changed at stage V. Morphological variations in larval development among individuals in the same instar were observed after instar IV. Early-stage phyllosomas of P. penicillatus were distinguished from other phyllosomas of the present genus in having two spinules on the proximal segment of the maxilla, in stead of three spinules in others.

Morphometry, Reproduction, Diet, and Epizoites of Ovalipes Stephensoni Williams, 1976 (Decapoda, Brachyura)

ABSTRACT Morphometry, reproductive biology, diet, and epizoite infestation of Ovalipes stephensoni (Brachyura: Portunidae) are described. The results are based on observations of 347 specimens collected by demersal trawl on the continental shelf of the eastern United States from 13-198 m, between 28° and 37°N, and on 26 specimens from the National Museum of Natural History collections in Washington, D.C. All seven morphometric relationships observed (carapace length, body depth, propodal length, width and depth of crushing chela, and abdominal width) exhibited allometric growth to some extent. Sexual dimorphism was demonstrated for chelar propodal length and abdominal width. Prepubertal and pubertal molts were inferred from two changes in allometry of the male chelar propodal length and female abdominal width. Allometric maturity was correlated with gonad, pleopod, and gonopore development. Males reach full maturity at a carapace width of 61 mm; females complete maturation by the time they reach 51 mm in width. Ovalipes stephensoni is heterochelic and heterodontic with the crushing claw occurring on the right side in 91.6% of the specimens observed. There is little evidence that cheliped laterality changes with age (size). Although this species is an opportunistic carnivore, bivalve mollusks, cephalopods, and small crustaceans comprised the bulk of the diet. Relatively heavy infestations of lepadid barnacles, Octolasmis muelleri, were found in the branchial chamber. Lesions of the ciliated protozoan Synophrya hypertrophica were present in the gill lamellae.

POST-LARVAL GROWTH OFDISSODACTYLUS PRIMITIVUSBOUVIER, 1917 (BRACHYURA: PINNOTHERIDAE) UNDER LABORATORY CONDITIONS

Dissodactylus primitivus is a small pinnotherid crab parasitic on spatangoid urchins. Post-larval growth has been observed in the laboratory in the absence of hosts. Individual animals were grown over the whole size range of the species for a period of 691 days after hatching. During growth of D. primitivus males and females, there was no significant change in carapace width with length. Relative to carapace width, male abdominal width increased isometrically. Growth of the female abdomen was allometric and could not be explained by a simple relationship. Two phases leading to sexual maturity were recognized: one of low positive allometry, the other of strong allometric growth. During the latter phase pubertal molts occurred.Growth over time showed decreasing increments and an increase in intermolt periods, with slight differences between sexes. The resulting growth rates closely fitted power curves. Compared to females, growth of males decreased after the first year. This could explain the presence of larger females in natural populations.Several growth relationships analogous to weight were demonstrated and the results discussed in relation to other Crustacea.

Morphometry, Reproductive Biology, and Diet of Acanthocarpus Alexandri Stimpson, 1871 (Decapoda, Brachyura) in the Middle Atlantic Bight

ABSTRACT Morphometry, reproductive biology, and diet of Acanthocarpus alexandri (Brachyura, Calappidae), captured on the eastern continental shelf of North America, are described. Carapace width was significantly longer than carapace length for the size range (CW: 6–44 mm) examined. Of the nine morphometric relationships observed, five dimensions exhibited allometric growth: width of propodus for male chelipeds, length of ischio-merus for female chelipeds, length of inferior meral spine for chelipeds of both sexes, width of the abdomen, and length of vulvae for females. Sexual dimorphism was demonstrated for body depth, abdominal width, and length of inferior spine of the chelipeds. Pubertal molts for females in the 18-24 mm range of carapace width were inferred from changes in allometry of vulval length and abdominal width. These alterations were correlated with gonad development and pleopod setation. Examination of testes and vasa deferentia indicated that males mature within a comparable size range. Acanthocarpus alexandri is an opportunistic carnivore and scavenger, feeding on a variety of benthic infauna.

Relative growth inNephrops norvegicus(L.) (Decapoda: Nephropidae)

Summary (1) Numerical values are given for the relative proportions of carapace length, total length, propodus length and total wet weight of Nephrops norvegicus from the Irish Sea. Where possible these values have been compared with those for animals from other areas. (2) Abdominal width and propodus length show changes in growth rate relative to the carapace length which have been ascribed to the onset of sexual maturity. The relative growth rate of the abdominal width in relation to carapace length is isometric, whereas the relative growth rate of propodus length is isometric, but positively allometric in males from sexual maturity onwards. (3) There were statistically significant differences between the body proportions of some populations of N. norvegicus. This may indicate the existence of races in discrete areas. (4) Handedness in N. norvegicus was investigated; animals with two similar claws are rare, particularly those with two crusher claws. The development of crusher and cutter claws is described.

Host Influence on the Bionomics of Trichogramma minutum1

The effect of host on the bionomics of Trichogramma minutum Riley was evaluated by comparing eggs of Trichoplusia ni (HA¼bner) and Sitotroga cerealella (Olivier) as hosts. Eggs of T. ni produced 2.45 times more parasite females than eggs of Sitotroga when stung individually and 2.27 times more females when stung in colonies. Parasite females from T. ni eggs were more fecund than those from Sitotroga eggs when both groups of females were attacking T. ni eggs, but the difference was nonsignificant when females from both hosts were attacking Sitotroga eggs or when they were attacking the species of host from which they were reared. Abdominal width greatly affected fecundity, but females from Sitotroga eggs were more fecund than females of the same size from T. ni eggs. Parasite females from Sitotroga eggs lived 1.35 times longer than females from T. ni eggs when only water was provided, but the difference was nonsignificant when diluted honey was fed. Parasite females from T. ni searched 1.97, 1.43, and 1.33 times more area than females from Sitotroga eggs. Thus, an egg of T. ni would provide parasite females traveling 2.60 times farther than females from an egg of Sitotroga. However, cost per million meters traveled would be 5.27 times greater with T. ni eggs than with Sitotroga eggs, because T. ni eggs cost more to produce.

Density, Growth and Reproduction in Populations of Astacus astacus and Pacifastacus leniusculus in an Isolated Pond

Pacifastacus leniusculus females mature in the third summer and males in the second. Corresponding ages for Astacus astacus are the fourth and the third summer, respectively. A positive correlation was obtained between the size of females and the number of pleopod eggs in both Astacus and Pacifastacus. Comparison of eggbearing females of Pacifastacus of the 90-99 mm size group with Astacus showed a lower egg production for Astacus. The differences in Rogle Ponds, Sweden were probably accentuated by pressure of food shortage on the dense Astacus population. Both males and females of Astacus and Pacifastacus reproduced every year after attaining adult size. Adult females of Pacifastacus had a greater relative abdominal width and a smaller egg diameter. The size of the adult population of Pacifastacus was estimated as 9,000 individuals. Before the outbreak of crayfish plague, the Astacus population was calculated as about 12,400 individuals. One-summer juveniles of Astacus were about 23 mm long, and of Pacifastacus about 40 mm. Two-summer males of Astacus averaged 49 mm, females 47 mm. The corresponding values for Pacifastacus were 82 and 79 mm, respectively.

Abdominal Width and Sexual Maturity of Female Lobsters on Canadian Atlantic Coast

The relative width of the second abdominal segment was used for comparing onset of sexual maturity of female lobsters in 18 different localities of the Maritime Provinces, after establishing a correlation between them. Judging by the abdominal width, the smallest lobsters to carry eggs range from 17.6 to 22.6 cm. long, and the sizes when approximately half the female lobsters are mature range from 23.5 to 29.2 cm. in the whole southern part of the gulf of St. Lawrence and along the outer Nova Scotian coast at least as far as Jeddore; in southern Nova Scotia and Grand Manan the corresponding ranges in size are higher, being 29 to 32 cm. and 36.7 to 40.4 cm. respectively. Graphs are given showing the relative abdominal width in 189 berried lobsters.

A Contribution to the Study of Relative Growth of Parts in Inachus Dorsettensis

ABSTRACT The relative growth-rate of the various parts of the body was investigated by analysis of linear measurements carried out on the carapace, appendages, and abdomen. The results were as follows: (a) The chelar propus shows strong positive heterogony in the 3 and very slight positive heterogony in the ♀. The ♂ chela shows dimorphism, the ♂♂ being differentiated into “high” and “low” forms and the dimorphism in all probability being due to the fact that the ♂ chela assumes the ♀ type of growth to a greater or less extent in the non-breeding season. (b) The pereiopods are more positively heterogonic in the ♂ than the ♀ and in both ♂ and ♀ there is a graded k series, but whereas in the ♂ k increases from P1—P4, in the ♀ the series is reversed k being greatest for P1. In both sexes the heterogony in the pereiopods is not so marked as that of the chelar propus. In the 3 the pereiopods suffer an actual decrease in absolute size at the time when the relative growth-rate is least for the chelar propus and after this period never again attain to their original relative size. (c) The third maxilliped is negatively heterogonic in both sexes and slightly more so in the ♂ than the ♀, although this difference may not be significant. (d) The abdomen in the ♀ shows marked positive heterogony in young crabs but is isogonic after the attainment of sexual maturity; in the ♂ the abdomen is isogonic in young crabs but becomes slightly negatively heterogonic in old animals. The abdomen in the ♀ is dimorphic, the “Tow” type (characteristic of the adolescent crab) being separated from the “high “type (characteristic of adult crab) by a single moult. There is considerable variation in the relative abdominal growth-rate in adolescent crabs and consequently in the time of attainment of sexual maturity and the full relative abdominal width. During the period of adolescence the increase in relative length and breadth is the same for all segments except the 5th, which forms a growth-centre for length. At the period of rapid conversion of the “low” type of abdomen into the “high” the 5th segment remains the growth-centre for length but a growth-centre for breadth is established in the 6th segment, and increase in relative breadth decreases from the distal to the more proximal segments. A comparison of the ♂ and ♀ as regards relative growth of parts was made and brought to light certain facts. All the pereiopods are relatively longer in the ♂ than the ♀. This is a graded effect—the actual difference in relative length (in ♂ and ♀) decreasing from P1—P4, but the increase in relative length relative to the actual size of the pereiopods increasing from P1—P4. These facts are interpreted as meaning that there is a common stimulating effect in the ♂, and also a retarding effect of the ♂ chela on the appendages posterior to it. It is tentatively suggested that the facts relating to the 3rd maxilliped are explained if we assume that the 3 chela has the same retarding effect on the anterior appendages as on those posterior to it. Certain general conclusions were drawn : (a) There is a different distribution of growth-potential in the two sexes, and strong positive heterogony is found associated with the development of the secondary sexual characters. (b) The results on the relative growth-rates of the appendages in ♂ and ♀ and on the growth-rates of the individual segments of the ♀ abdomen, indicate the presence of definite gradients in the body, in relation to which growth takes place. (c) The growth-centre for the heterogonic organs is situated towards the distal end of the organ; this is in agreement with results obtained for other Crustacea.