Cranial morphology and osteology of the sexually dimorphic electric fish, Compsaraia samueli Albert & Crampton (Apteronotidae, Gymnotiformes), with comparisons to C. compsa (Mago-Leccia)

Zootaxa ◽  
2019 ◽  
Vol 4555 (1) ◽  
pp. 101 ◽  
Author(s):  
RACHEL KEEFFE ◽  
ERIC J. HILTON ◽  
MÁRIO J. F. THOMÉ DE SOUZA ◽  
CRISTINA COX FERNANDES
Keyword(s):  
Sexual Dimorphism ◽  
The Body ◽  
Cranial Morphology ◽  
Sexually Dimorphic ◽  
Anterior Portion ◽  
Lower Jaw ◽  
Wide Range ◽  
The Family ◽  
Body Sizes ◽  
Cranial Osteology

Sexual dimorphism of the snout has evolved independently in at least four separate clades of the gymnotiform family Apteronotidae. This phenomenon may help identify sex, except in the absence of mature individuals, and has led to confused taxonomy for several species. We examined a large collection of Compsaraia samueli collected during the breeding season from a remote stream in the Rio Negro drainage. This collection contains a wide range of sizes of both sexes, but most individuals were easily identified as mature. To quantify the sexual dimorphism of these specimens, 15 measurements were taken from the head and the body. In addition, some specimens were cleared-and-stained to study cranial osteology. We found that long-snouted males of C. samueli span a wide range of body sizes. As the snout length increases the distance between the eye and the occiput does not increase at the same rate, suggesting that it is only the anterior portion of the head that has an increased allometry. Skeletal anatomy differs between the sexes in that the lower jaw is more triangular in females and more linear in males. The coronomeckelian is small and round in females in contrast to being longer and pointed in males. There is strong interlacing of the dentary and anguloarticular bones in males, whereas this contact is not as extensive in females. We also discuss the implications of sexual dimorphism for identification of this species relative to its congener (C. compsa), and for the evolution of sexual dimorphism in the family. 

Comparative study of the cranial morphology of the labrids Choeroden venustus and Labroides dimidiatus and the scarid Scarus fasciatus (Pisces : Perciformes) I. Head skeleton

1980 ◽  
Vol 31 (3) ◽  
pp. 337 ◽  
Author(s):  
RA Tedman
Keyword(s):  
Fibrous Tissue ◽  
Cranial Morphology ◽  
Alveolar Process ◽  
Forward Movement ◽  
Host Fish ◽  
Lower Jaw ◽  
The Family ◽  
Fused Teeth ◽  
Cranial Osteology ◽  
Head Skeleton

The cranial osteology of C. venustus, L. dimidiatus and S. fasciatus is described. C. venustus and L. dimidiatus possess three features characteristic of the family Labridae: protrusible upper jaws, the ascending process of the maxilla longer than the alveolar process, and the alveolar process of the premaxilla attached by fibrous tissue to the distal end of the maxilla which in turn is fastened to the ascending process of the dentary. The neurocranium of C. venustus shows several features involved in strengthening the skull to withstand the strong forces applied during feeding when crushing molluscs, barnacles and crabs as well as turning over slabs of coral. The forward movement of jaws and eyes have permitted L. dimidiatus to feed by picking small organisms off the general body surface, pharynx, gills and buccal cavity of host fish. S.fasciatus has at least three features characteristic of scarids: fused teeth on the premaxillae and dentary, a premaxilla firmly attached to the maxilla, and a secondary joint between the dentary and articular producing a compound lever type of articulation for the lower jaw. Several modifications help strengthen the upper and lower jaws and enable S. fasciatus to feed by scraping pieces of algae and coral fragments from the surfaces of coral rocks.

scholarly journals The body-size dependence of mutual interference

2014 ◽  
Vol 10 (6) ◽  
pp. 20140261 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Size Dependence ◽  
Empirical Support ◽  
Mutual Interference ◽  
The Body ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Body Sizes ◽  
Size Scales

The parameters that drive population dynamics typically show a relationship with body size. By contrast, there is no theoretical or empirical support for a body-size dependence of mutual interference, which links foraging rates to consumer density. Here, I develop a model to predict that interference may be positively or negatively related to body size depending on how resource body size scales with consumer body size. Over a wide range of body sizes, however, the model predicts that interference will be body-size independent. This prediction was supported by a new dataset on interference and consumer body size. The stabilizing effect of intermediate interference therefore appears to be roughly constant across size, while the effect of body size on population dynamics is mediated through other parameters.

Jaws and radula of the Carboniferous ammonoid Cravenoceras

1995 ◽  
Vol 69 (4) ◽  
pp. 703-707 ◽  
Author(s):  
Kazushige Tanabe ◽  
Royal H. Mapes
Keyword(s):  
The Body ◽  
Anterior Portion ◽  
Phylogenetic Affinity ◽  
Body Chamber ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Marginal Plates ◽  
Buccal Space

A well-preserved mouth apparatus consisting of jaws and a radula was found in situ within the body chamber of the goniatite Cravenoceras fayettevillae Gordon, 1965 (Neoglyphiocerataceae: Cravenoceratidae), from the middle Chesterian (Upper Mississippian) of Arkansas. Both upper and lower jaws consist of a black material. The lower jaw is characterized by a widely opened larger outer lamella and a shorter inner lamella. The upper jaw is fragmental. The radula is preserved in the anterior portion of the buccal space and comprises a series of tooth elements. Each transverse tooth row consists of seven teeth (a rhachidian and pairs of two lateral and one marginal teeth), with a pair of marginal plates. This arrangement is typical of radulae of other ammonoids of Carboniferous to Cretaceous age, coleoids, and the orthoconic “nautiloid” Michelinoceras (Silurian, Michelinocerida), suggesting a phylogenetic affinity among them.

Some new and known species of Bomolochidae (Copepoda, Cyclopoida) parasitic on Japanese actinopterygian fishes, 1 — with discussion on sexually dimorphic features in the family

Crustaceana ◽  
2020 ◽  
Vol 93 (8) ◽  
pp. 891-929
Author(s):  
Kunihiko Izawa
Keyword(s):  
Sexual Dimorphism ◽  
Sexually Dimorphic ◽  
The Family ◽  
Actinopterygian Fishes ◽  
Copepoda Cyclopoida

Abstract Three new and five known species of Bomolochidae Claus, 1875, parasitic on Japanese actinopterygian fishes, are (re)described. They are Bomolochus bellones Burmeister, 1835, B. decapteri Yamaguti, 1936, B. hoi sp. nov., Naricolax sphyraenae sp. nov., Nothobomolochus cypseluri (Yamaguti, 1953), Orbitacolax brevispinus Moon, Choi & Venmathi Maran, 2018, O. scombropsi sp. nov., and O. unguifer Kim & Moon, 2013. The copepodid IV female of B. bellones, the male and copepodid IV female of Na. sphyraenae, the male and copepodid IV and V female of No. cypseluri and O. unguifer are herein described. Sexual dimorphism is found in the antennule, maxilliped, and legs in the family.

An interesting sexually dimorphic species, Neoribates isabelaensis sp. nov. (Acari, Oribatida, Parakalummidae) with remarks on sexual dimorphism in Oripodoidea 

Zootaxa ◽  
2017 ◽  
Vol 4347 (1) ◽  
pp. 94
Author(s):  
BADAMDORJ BAYARTOGTOKH ◽  
SERGEY G. ERMILOV ◽  
LEONILA CORPUZ-RAROS
Keyword(s):  
Sexual Dimorphism ◽  
Posterior Part ◽  
The Philippines ◽  
Similar Species ◽  
Sexually Dimorphic ◽  
The Family ◽  
Pheromonal Communication ◽  
Large Round ◽  
Dimorphic Species ◽  
A New Species

A new species Neoribates isabelaensis sp. nov. showing an interesting sexual dimorphism is described from bamboo litter on Luzon Island in the Philippines. This species is unique among other species of Neoribates in the structure of the posterior part of notogaster in males, which has a large round concavity bearing a pair of large sacculi S3. The specific function of this structure is not yet known, but the found sexual dimorphism is presumably involved in pheromonal communication allowing rapid sperm transfer. This is the fourth Neoribates species displaying sexually dimorphic characters. Additionally, Neoribates isabelaensis sp. nov. differs from the morphologically most similar species, Neoribates barbatus Hammer, 1968, by its smaller body size, pointed rostrum, long and setiform bothridial setae and the localization of notogastral setae h1 and h2, which insert close to each other. Further, we discussed all cases of sexual dimorphism in the family Parakalummidae as well as other related groups of Oripodoidea, and the possible function of these modifications. 

Indicators of chemiluminescent and bioluminescent tests of biological liquids in the assessment of physical health

2020 ◽  
Vol 65 (9) ◽  
pp. 541-546
Author(s):  
Svetlana Nikolaevna Derevtsova ◽  
A. A. Romanenko ◽  
O. A. Kolenchukova ◽  
L. V. Stepanova ◽  
V. G. Nikolaev ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Young Male ◽  
Antioxidant Defense System ◽  
The Body ◽  
Antioxidant Protection ◽  
Body Type ◽  
Sexual Characteristics ◽  
Body Sizes ◽  
Sex Inversion ◽  
Biological Liquids

The study includes anthropometry of 172 young male, obtained data on the length and body mass, measured the transverse diameters of the shoulders and pelvis, various body types was identified by the J.M. Tanner sexual dimorphism index (andromorphic, mesomorphic, gynecomorphic). The chemiluminescent and bioluminescent study of saliva and blood was conducted in the examined young male. We studied the indicators of the antioxidant defense system under the influence of stress. The antioxidant status of saliva was determined using the H2O2-luminol-dependent chemiluminescence method. Data on the activity of NAD (P) -dependent dehydrogenases in blood lymphocytes was obtained from a bioluminescent method of research. Young male of andromorphic body type had large overall and transverse body sizes. Indicators of antioxidant protection of saliva and blood in men of adolescence, the body type of the sexual dimorphism index J.M. Tanner was different. The persons of the andromorphic body type differed in terms of chemiluminescence in comparison with the young male of gynecomorphic body type. The results of bioluminescent blood tests suggest a violation of the catabolic and anabolic processes of carbohydrate and fat metabolism in young men of mesomorphic and gynecomorphic body types. Indicators of the system of antioxidant protection of saliva and blood reflect the sexual characteristics of the body of young male and can be used as additional criteria for diagnosing sex inversion and assessing the risk of developing socially attributed diseases.

Avian Egg Morphometrics - Allometric Models of Egg Volume, Clutch Volume and Shape

1994 ◽  
Vol 42 (3) ◽  
pp. 307 ◽  
Author(s):  
PD Olsen ◽  
RB Cunningham ◽  
CF Donnelly
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Clutch Size ◽  
Egg Volume ◽  
Simple Power ◽  
Wide Range ◽  
Body Weights ◽  
Body Sizes ◽  
Simple Power Function

This paper describes three comprehensive new models of the allometric relationships between egg volume, clutch volume and shape, and body weight. Mean egg dimensions, clutch sizes and adult body weights were obtained for 326 species, mainly of four bird types: raptors (including owls), shorebirds, frogmouths (including nightjars), and storks (including the New World vultures). These are groups in which there is a wide range of body sizes and of sexual dimorphism in body size (in direction and degree). Female body weight alone accounted for 92% of the variation in egg volume. Sexual dimorphism in body size, phylogenetic relationship, and clutch size were significant contributors to the model of egg volume; their addition increased the explained variance to over 98%. The model was curvilinear (quadratic) in form, rather than linear as assumed in previous models. Larger species laid smaller eggs than expected under a simple power function. For the fitted model, within bird types, generic groupings had parallel curvilinear slopes but differing intercepts. Between bird types, the slopes differed. Clutch volume was scaled to body weight; all the bird types had a common slope, which was curvilinear. Body weight and dimorphism accounted for 89.5% of the variation in clutch volume. For all bird types, eggs became proportionally longer in shape as body weight increased, according to a simple power law. The relevance of these relationships to hypotheses on the evolution and adaptive significance of sexual dimorphism and to the trade-off between egg size and clutch size is discussed briefly.

scholarly journals Sexual dimorphism in the Spotted Stinger Inimicus sinensis (Valenciennes, 1833) and notes on pore structures on the body

2020 ◽  
Vol 13 (1) ◽  
Keyword(s):  
Sexual Dimorphism ◽  
Principal Component ◽  
The Body ◽  
Body Region ◽  
Head Width ◽  
Base Length ◽  
Morphometric Characters ◽  
Lower Jaw ◽  
Meristic Counts ◽  
Fin Ray

Spotted stinger individuals, Inimicus sinensis, collected from Carles, Iloilo, Philippines exhibited previously-unreported sexual dimorphism. Thirty-three morphological measurements, including standard length, and fourteen meristic counts from 99 specimens (47 males and 52 females) were analyzed for sexual dimorphism. Most morphometric characters differed significantly between the sexes, whereas no differences were found in meristic counts. Dorsal and anal-fin and free pectoral-fin ray lengths were greater in male specimens. On the other hand, the head and body region were relatively larger in female specimens. Principal Component Analysis (PCA) extracted two principal components from significantly different parameters, which explained 62.29 % of the cumulative variances. Variations in the two major components resulted from: head width, upper jaw, lower jaw, snout, pre-dorsal, pre-anal-fin, and anal-fin base lengths in PC1 (45.65 %); and orbit diameter and anal-fin base length in PC2 (16.64 %). Additionally, a single anterolateral pore on the body and pores above the lateral-line are described, although no evidence of association with other organs was found.

Body size and segmentation patterns in free-living and parasitic polychaetes

2001 ◽  
Vol 79 (5) ◽  
pp. 741-745 ◽  
Author(s):  
Robert Poulin
Keyword(s):  
Life History ◽  
Body Length ◽  
Life History Traits ◽  
The Body ◽  
Free Living ◽  
Body Segments ◽  
The Family ◽  
Body Sizes ◽  
Number Of Segments ◽  
Over Time

Taxa that include both free-living and parasitic lineages present opportunities to examine if and how the life-history traits of parasitic organisms have diverged from those of their free-living relatives. In a comparative analysis the body sizes and numbers of body segments of parasitic polychaetes of the family Oenonidae were compared with those of free-living polychaetes from closely related families. There was no difference in body length between oenonids and free-living polychaetes. However, the parasitic oenonids attain, on average, a much higher number of body segments than their free-living counterparts. The number of segments per unit body length is also much higher in oenonids than in related free-living polychaetes. This suggests that new segments are produced at a higher rate or for longer periods in oenonids than in free-living polychaetes, in which the proliferation of new segments slows down over time to allow for the segments to grow in size. Given that each segment can produce gametes late in the life of the worm, the proliferation of segments in oenonids may be an adaptation to their parasitic life-style.

Memorialising and Forgetting: Corporeal Generosity and the Gift of the Intersexed Other

Somatechnics ◽  
2011 ◽  
Vol 1 (2) ◽  
pp. 272-297 ◽  
Author(s):  
Jessica Robyn Cadwallader
Keyword(s):  
Sexual Dimorphism ◽  
Surgical Intervention ◽  
The Body ◽  
The Political ◽  
Sexually Dimorphic ◽  
Corrective Surgery ◽  
The Gift ◽  
Technological Intervention

‘Modifying bodies’ evokes two different kinds of bodies, too often thought of as separate: those bodies which are modified, and those which call for and enact the modification. This paper seeks to explore the ethical and political significance of the modification of ‘intersexed’ bodies, using Rosalyn Diprose's concept of ‘corporeal generosity’. It argues that the visceral reaction to the bodies of those not recognised within the regimes of sexual dimorphism is shaped by perceptual practices formed through the political memorialising of the generosity of particular, privileged others, and the forgetting of the generosity of othered others. These patterns of memorialising and forgetting also shape the call for surgical intervention, such as ‘corrective’ surgery, performed on the body of the intersexed child, become the means for memorialising the gifts of the sexually dimorphic, and forgetting the gifts of those deemed ‘ambiguous’. This approach enables the ethical and political significance of this technological intervention to be understood as of a piece with larger somatechnics, shared, challenged and perpetuated through corporeal generosity.

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