Lower Jaw Length Research Articles

Phenotypic covariation predicts diversification in an adaptive radiation of pupfishes.

Phenotypic covariation among suites of traits may constrain or promote diversification both within and between species, yet few studies have empirically tested this relationship. In this study, we investigate whether phenotypic covariation of craniofacial traits is associated with diversification in an adaptive radiation of pupfishes found only on San Salvador Island, Bahamas (SSI). The radiation includes generalist, durophagous, and lepidophagous species. We compared phenotypic variation and covariation (i.e., the P matrix) between (1) allopatric populations of generalist pupfish from neighboring islands and estuaries in the Caribbean, (2) SSI pupfish allopatric lake populations with only generalist pupfish, and (3) SSI lake populations containing the full radiation in sympatry. Additionally, we examine patterns observed in the P matrices of two independent lab-reared F2 hybrid crosses of the two most morphologically distinct members of the radiation to make inferences about the underlying mechanisms contributing to the variation in craniofacial traits in SSI pupfishes. We found that the P matrix of SSI allopatric generalist populations exhibited higher levels of mean trait correlation, constraints, and integration with simultaneously lower levels of flexibility compared to allopatric generalist populations on other Caribbean islands and sympatric populations of all three species on SSI. We also document that while many craniofacial traits appear to result from additive genetic effects, variation in key traits such as head depth, maxilla length, and lower jaw length may be produced via non-additive genetic mechanisms. Ultimately, this study suggests that differences in phenotypic covariation significantly contribute to producing and maintaining organismal diversity.

Morpho-meristic characteristics and growth pattern of walking snakehead (Channa orientalis) collected from different locations of Northwestern Bangladesh

This study aimed to reveal the morphometric and meristic variations, length-weight relationships, and condition factor of Channa orientalis collected from three regions (Kurigram, Rangpur, and Lalmonirhat districts) of Northwestern Bangladesh. Fifteen morphometric and six meristic characteristics were selected. Eight morphometric characteristics were significantly different (p<.05) among the regions; three characteristics were highly significant (p<.001) in Kurigram (Pre-orbital distance, PrOD; Lower-jaw length, LJL; Upper-jaw length, UJL) indicating C. orientalis population of Kurigram was significantly different (p<.001) from the other two locations. On the other hand, among six meristic characteristics, number of dorsal fin rays (DFR), pectoral fin rays (PFR), anal fin rays (AFR), and branchiostegal rays (BR) were found to be significantly different among three locations. The values of PFR varied significantly (p<.05) in Kurigram, which distinguishes the other two regions. Likewise, DFR and BR showed significant variations in the Rangpur region, whereas AFR significantly (p<.001) separated the Lalmonirhat population from the others. In length-weight relationships, the generalized relationship between total length (TL) and body weight (BW) were BW=0.007TL3.147 (r2=0.945), BW=0.03TL2.573 (r2=0.916) and BW=0.008TL3.084 (r2=0.899) for Kurigram, Rangpur, and Lalmonirhat, respectively. The growth pattern showed positive allometric in Kurigram (b=3.14) and Lalmonirhat (b=3.08). Negative allometric was observed in Rangpur (b=2.57). The study exhibited a higher condition factor (K) value in Kurigram (1.068) and Rangpur (1.049) whereas the lowest in Lalmonirhat (0.978). The study reveals that the C. orientalis population`s morpho-meristic and growth status were comparatively better in Kurigram region.

POPULATION DIVERSITY BASED ON MORPHOMETRIC MERISTIC ENDEMIC BUTINI FISH (Glossogobius matanensis) IN LAKE TOWUTI, SOUTH SULAWESI

Butini fish is a resource wealth of fauna found only in the East Complex Malili Luwu, South Sulawesi. The necessary information about the morphological characters (morphometric and meristic) to determine the management of fish resources. The purpose is to assess the diversity of populations based on morphometric meristik. Sampling is based on descriptive methods and fish samples taken to determine the diversity of phenotypes based on the depth of each morphometric character. Calculating morphometric characters using the main component analysis to obtain the correlation between the character and the grouping of individuals based on morphometric characters. Calculation meristik characters include the number of fingers, the number of fins and scales, namely the number of fingers of the dorsal fin, anal fin radius, the radius of the ventral fin, pectoral fin radius, the radius of the caudal fin, scales on the rib line, scales above the rib line, scales below the ribs, scales in front of the dorsal fins, scales on the cheeks, around the body scales, scales around the tail shaft. The analysis showed that the first two principal components contained the greatest information, with a cumulative range of 80%. All the characters' morphometric first role is a major component. The character who plays the main component of the length of the head in front of the eyes, long upper jaw, lower jaw length, high cheeks, and the length of the radius of a weak base ventral fins showed great correlation to the diversity of forms. Main components analysis also showed that butini fish, at any depth, showed no grouping. This suggests that the fish species observed was one (one unit of population). In calculating the value of phenotypic diversity of each character, butini generally fish in the lake Towuti show morphometric characters with the highest diversity value and the lowest given by the total length and high under the eyes. In the calculation of the formula derived characters meristik flipper fingers that D1, V-VI. D2. I, 8-11; dan D1, V-VI, D2. I, 8-10.

Morphometric characters of the whitefish ludoga (coregonus lavaretus ludoga) in connection with the lake Issyk-Kul ecological and geographical conditions and its introduction

This article considers the influence of ecological and geographical conditions in the sequent whitefish ludoga (Coregonus lavaretus ludoga) relocation from Lake Ladoga to Lake Sevan and then from Lake Sevan to Lake Issyk-Kul. Morphometric studies of whitefish ludoga from Lake Issyk-Kul and a comparative analysis with similar data of this fish species of Lake Ladoga and Lake Sevan were carried out, taking into account the ecological and geographical condition of these lakes. In the course of our research, we found that the morphometric characters of whitefish ludoga during the introduction from Lake Ladoga to Lake Sevan and then to Lake Issyk-Kul changed due to the ecological and geographical conditions of these lakes. We have identified changes that occurred sequentially when moving from the plain region lake (Ladoga) to the mountain lake (Sevan) and to the mountain lake with brackish water (Issyk-Kul). These changes were mainly in the quantitative increase of some morphological parameters of these fish, such as raker counts on first branchial arch; scale counts on the lateral line; snout length and lower jaw length; predorsal distance and caudal peduncle length; head depth. In addition, there are changes characteristic of the Issyk-Kul fish, it is an increase in body depth and the dorsal fin height.

FishShapes v1: Functionally relevant measurements of teleost shape and size on three dimensions.

Teleost fishes account for 96% of all fish species and exhibit a spectacular variety of body forms. Teleost lineages range from deep bodied to elongate (e.g., eels, needlefish), laterally compressed (e.g., ribbonfish) to globular (e.g., pufferfish), and include uniquely shaped lineages such as seahorses, flatfishes, and ocean sunfishes. Adaptive body shape convergence within fishes has long been hypothesized but the nature of the relationships between fish form and ecological and environmental variables remain largely unknown at the macroevolutionary scale. To facilitate the investigation of the interacting factors influencing teleost body shape evolution we measured eight functionally relevant linear traits on adult-sized specimens along with specimen mass. Linear measurements of standard length, maximum body depth, maximum fish width, lower jaw length, mouth width, head depth, minimum caudal peduncle depth, and minimum caudal peduncle width were taken in millimeters with calipers, or tape measures for oversized specimens. We measured these traits on a total of 16,523 specimens (1-3 specimens per species) at the Smithsonian National Museum of Natural History and took approximately 7000 person hours of data collection to complete. The data went through a three-step error-checking process to clean and validate the data and then species averages were calculated. We present the complete specimen data set, which encompasses approximately one-fifth of extant teleost species diversity, spanning ~90% of teleost families and ~96% of orders. The species and family names are compatible with the taxonomy used by FishBase and the order information with the phylogenetically informed taxonomy of Betancur-R and colleagues published in 2014. This dataset is licensed under Creative Commons CC0 1.0 Universal (CC0 1.0) but please cite this paper when using the data or a subset of it.

Longline Hook Selectivity for Branchiostegus japonicus (Houttuyn, 1782) and Dentex tumifrons (Temminck & Schlegel, 1843) in the East China Sea

Bottom longline fishing of red tilefish (Branchiostegus japonicus) is one of the most important commercial of fishing in the East China Sea. The present study aimed to investigate hook selectivity in B. japonicus and D. tumifrons, by means of experiments using three hook sizes (“J”: #15, #13 and #11) and was conducted in the East China Sea from June to August 2018. Altogether 602 B. japonicus fish and 858 D. tumifrons fish were caught. With respect to the size of the hook used, the total length-frequency varied significantly for both B. japonicus and D. tumifrons that were caught. The total length and four mouth parameters (upper and lower jaw length as well as height and width of mouth opening) of the two species showed a positive linear relationship. A logistic model created using the maximum likelihood method was used for elucidating hook selectivity; the best fit model with the minimum Akaike’s Information Criterion value was selected as the final model. The 50% selection lengths were 224.827 and 233.179 mm for B. japonicus; 201.461 and 202.603 mm for D. tumifrons using “J” #13 and “J” #11 hooks, respectively. To preserve the reproductive potential of younger fish in the stocks, the size of the “J” #13 hook was selected as the minimum hook size that should be used for the sustainable development of bottom longline fishing for B. japonicus and D. tumifrons.

Sex Determination of Dry Human Mandible Using Metrical Parameters in Mahakaushal Region of Madhya Pradesh, India: A Cross-sectional Study

Introduction: Determination of sex and age from skeletal remains is not only important for forensic science but also for Anatomy, Forensic Odontology, Anthropology and Palaeontology examination. Mandible next to the pelvis in human remains help us in the identification of age, sex, and race. Aim: To determine sex by using metrical parameters in dry human mandible. Materials and Methods: This cross-sectional study contained 104 dry human mandibles of undetermined age and unknown sex (as they were not recorded at the time of acquisition) belonging to the Indian population was obtained from NSCB Medical College, Jabalpur, Madhya Pradesh, India. All adult (mandible with presence of bilateral molar teeth; prominent alveolar sockets; intact condylar and coronoid processes; well- developed bone), intact and well-formed mandible were taken and broken, deformed, pathological bones were excluded. Statistically analysed by using Statistical Package for Social Sciences (SPSS) for Windows, version 16.0. results: Out of the 13 parameters studied statistically highly significant difference in sex was observed in bicondylar breadth, bigonial breadth, coronoid breadth, angle of mandible, mandibular length, diagonal length and coronoid height, length of lower jaw. conclusion: The present study utilises the 13 different metrical parameters. The application of these 13 metrical parameters along with morphological features could be a useful tool for sex determination of the mandible.

Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters.

Eelpout species of the genus Lycenchelys Gill, 1884 recorded from Japanese waters are taxonomically revised. This study recognizes the following 11 species from Japanese waters as valid: Lycenchelys albomaculata Toyoshima, 1983, Lycenchelys aurantiaca Shinohara Matsuura, 1998, Lycenchelys hippopotamus Schmidt, 1950, Lycenchelys maculata Toyoshima, 1985, Lycenchelys makushok Fedorov Andriashev, 1993, Lycenchelys melanostomias Toyoshima, 1983, Lycenchelys rassi Andriashev, 1955, Lycenchelys remissaria Fedorov, 1995, Lycenchelys ryukyuensis Shinohara Anderson, 2007, Lycenchelys squamosa Toyoshima, 1983 and Lycenchelys tohokuensis Anderson Imamura, 2002. We redescribe species in detail based on type specimens as well as additional specimens in many cases. The synonymy of Lycenchelys brevimaxillaris Toyoshima, 1985 with L. melanostomias is supported in this study. Sexual dimorphism and changes with growth are revealed in L. albomaculata, L. aurantiaca, L. hippopotamus, L. makushok, L. melanostomias and L. rassi, all based on 10 or more specimens, for relative head length, head width, and upper and lower jaw lengths. In addition, we also found that the sizes at which sexual dimorphism can be recognized, and the tendencies for change with growth, differ among species. Furthermore, the dimorphism in head length is influenced by the snout length, eye diameter and/or postorbital length in L. albomaculata and L. aurantiaca.

Phenotypic diversity in an endangered freshwater fish Squalius microlepis (Actinopterygii, Leuciscidae).

Squalius microlepis was examined from recent and historical collections within the known range of the species with special emphasis on intraspecific variability and variations, and compared to its closest relative species S. tenellus (in total, 193 specimens; 33 absolute and 52 proportional measurements and ratios, and 12 counts including vertebrae). Squalius tenellus was perfectly differentiated in all statistical analyses and can be diagnosed by 76–95 (vs. 64–80) scales in lateral series, 68–83 (vs. 58–77) lateral-line scales, (17)18–20 (vs. 13–16(17)) scales above lateral line, and (7)8–10 (vs. 4–7) scales below lateral line. Squalius microlepis was morphologically heterogeneous, with two phenotypes readily distinguishable (phenotype 1 corresponding to S. microlepis s. str. as defined by its lectotype) by a combination of many characters; those contributing most to the discrimination were number of gill rakers, length of lower jaw (% interorbital width), and head length (% SL). Only phenotype 1 was found in the Ričina-Prološko Blato-Vrljika karst system; most of the specimens from the lower Matica and the Tihaljina-Trebižat karst system were identified as phenotype 2; the sample from karstic poljes near Vrgorac contained both phenotype 1 and 2, and individuals of intermediate morphology. As very limited molecular data exist on the two phenotypes of S. microlepis, we refrain from any taxonomic conclusions until new molecular approaches (and new markers) are used. We also report on a dramatic reduction of the area of distribution and abundance of S. microlepis in recent years.

Adaptive downsizing in the piscivorous cyprinid fish, Opsariichthys uncirostris, facilitates rapid establishment after introduction to a small-scale habitat in Japan

The three-lips (Opsariichthys uncirostris) is a piscivorous cyprinid fish native to the Biwa Lake, central Japan. A recent unintentional introduction of the species has led to its invasion of a novel, small-scale habitat (the Futatsu River) composed of a few riverine stretches connected by irrigation ditches. Comparative observations of fish samples from both habitats provide evidence of disparities in the fish’s size at maturity between the two habitats, with fish in the Futatsu River reaching maturity at smaller body sizes. Achieving a large body size at maturation requires a larger habitat offering a sufficient supply of food. Principle component analysis of body-surface morphometric characteristics revealed that the two populations show differences in both their body shape and growth rates. In the Futatsu River, the growth rates of upper jaw length, lower jaw length, eye diameter, predorsal length, and tail length were accelerated, while the growth rates of head depth, body depth, and tail depth were decelerated, leading to the acquisition of a distinctly slender body. It is plausible that small-scale habitats with less abundant food supplies favor sexual maturation at smaller body sizes and that slender bodies improve swimming performance, thus making such disproportional downsizing a consequence of adaptation to a novel environment. Whether this change is due to phenotypic plasticity or rapid evolution remains unknown.

Meristic and Morphometric Variations of Barred Spiny EEL Macrognathus pancalus Populations from Bangladeshi Freshwaters: An Insight Into Landmark-Based Truss Network System

Abstract The present research focuses to examine the meristic and landmark-based morphometric variations of barred spiny eel Macrognathus pancalus from four populations namely Dhakuria beel, Jessore (DBJ); Bohnni boar, Gopalgonj (BBG); the Arial kha river, Madaripur (AKRM) and the Nabaganga river, Jhenidah (NRJ) in Bangladeshi freshwaters. Six meristic counts were compared among four populations and significant differences were observed in number of caudal fin rays and number of pelvic fin rays in all meristic characters. The truss protocol was used in the present study based on six general morphometrics and fifteen truss measurements. Univariate statistics showed that five (standard length (SL), upper jaw length (UJL), lower jaw length (LJL), head depth (HD) and inter orbital (IO)) of six morphometric and eleven truss networks (viz. 2-3, 3-4, 5-6, 6-7, 7-8, 1-8, 2-8, 3-8, 3-7, 4-7 and 5-7) among fifteen truss measurements differed significantly. Cannonical discriminate function analyses were conducted among samples and the populations were fully intermingled. Pooled within-group correlation showed morphometric and landmark measurements; the first discriminant function (DF) accounted for 79%, the second DF accounted for 15.9% and third DF accounted for 5.1% of group variability. An euclidian dendrogram was prepared based on morphometric and truss measurements in four populations, where two clusters were mainly formed, in which first cluster formed by NRJ population was fully separated, and the second cluster was formed by two populations of AKRM and DBJ. Additionally, a subcluster BBG was formed with AKRM. On the basis of morphometric and truss measurements, 68.8%, 83.6%, 55.6% and 80% of original grouped cases were correctly classified in NRJ, AKRM, DBJ and BBG, respectively. These results specify the presence of different stocks of fish from four aquatic habitats. This study is highly significant for proper conservation and effective management of M. pancalus populations as well as for the scientific community for further research.

Three-dimensional study of the upper airway in different skeletal Class II malocclusion patterns.

To characterize upper airway volume and morphology in patients with different skeletal patterns of Class II malocclusion compared to Class I. A total of 197 individuals who had cone-beam computed tomography were allocated into groups according to ANB, SNA, and SNB angles (Class I, Class II maxillary protrusion, Class II mandibular retrusion), each subdivided into hypodivergent, normal, and hyperdivergent. Nasopharynx (NP), oropharynx (OP), and hypopharynx (HP) were assessed with three-dimensional image reconstruction software. Intergroup comparison did not detect significant differences in volume and morphology of NP, OP, and HP. The males displayed larger OP and HP volume than the females. Positive correlations between age and NP, OP, HP volume and between craniocervical angle and OP and HP volume were observed. Linear regression analysis detected a tendency for OP and HP volume to increase as maxillary and mandibular length increased. Upper airway volume and morphology were similar in different skeletal patterns of Class II malocclusion. Actual upper and lower jaw lengths were more closely related to upper airway volume and morphology than the angles that reflected their position relative to the cranial base.

The Prediction of Prolificacy Using Linear Body Parameters and Craniometric Analysis in Etawah-Grade Does

Etawah-grade goat is a graded up line between Kacang and Etawah goats, which well adapted to Indonesia’s humid tropical climate. In order to fulfill national meat requirement, it is necessary to increase the population by increasing prolificacy. This study was aimed to determine whether the body and head measurements of the Etawah-grade does can be used as selection criteria for indirect selection of the litter size. The use of does at 3-4 years old (I3 dental condition) from BPTU-HPT Pelaihari and Cordero farms (51 and 55 does, respectively) were based on their specific geographical location characteristics. The body variables were withers height, hip height, body length, chest width, chest depth, thurl width, rump length, chest girth, and cannon circumference, whereas for head variables were acrocranion–prosthion, basion–prosthion, lower jaw length, head height, tuber facial left-right, nasion–rhinion, entorbitale left-right, euryon left-right, supraorbitale left-right. Bergmann methods were applied for measuring the differences of body and head parameters followed by the principal component, Fisher’s discriminant, and principal component regression analyzes. All regression coefficients of linear body measurementss were highly correlated to the litter size (P<0.01), with the equation was Y= 0.015X1b + 0.011X2b + 0.025X3b - 0.002X4b + 0.022X5b + 0.010X6b + 0.022X7b + 0.030X8b + 0.026X9b. The chest girth was the most elastic body size measurement to the litter size. The increasing of 1 cm of doe’s chest girth would result in the increase of litter size, each of 0.0545 and 0.0417 heads born-1 at BPTU-HPT Pelaihari and Cordero farms. Differences in head size and head shape due to the morphometric adaptations cannot be used to predict litter size.

Profil Hormon Progesteron dan Gen Fekunditas terhadap Sifat Kembar Kambing PE Betina Calon Induk

Etawah-grade goat is a graded up line between kacang and etawah goats, which well adapted to Indonesia’s humid tropical climate. The good reproductive trait of Etawah-grade does are inherited from kacang goat (prolific goat). This study used six heads of Etawah-grade does at 1–2 years old (I1 dental condition). IPB University. The body variables were withers height, hip height, body length, chest width, chest depth, thurl width, rump length, chest girth, and cannon circumference, whereas for head variables were acrocranion–prosthion, basion–prosthion, lower jaw length, head height, tuber facial left-right, nasion–rhinion, entorbitale left-right, euryon left-right, supraorbitale left-right. Body score and head score were obtained from Principal Component Analysis (PCA). PCR-RFLP technique was used to determine genotypes of fecundity genes BMP15 (exon 1), BMPR1B (exon 1), KISS1 (exon 1) and KISS1 (intron 1) with restriction enzymes AluI (AG|CT), SduI (GDGCH|C), BsrI (ACTGG|) and MwoI (GCCTAAG|TAGC), respectively. Progesterone leves were measured by EIA (enzyme immuno assay). The results showed that the association between crude fat consumption and progesterone profile was found in this study, but it was not related to twin births with certain genotypes of gene fecundity BMP15 (exon 1), BMPR1B (exon 1), KISS1 (exon 1) and KISS1 (intron 1). The progesterone profile during the pregnancy period did not correlate to their body size and head size.

Shape analysis of the jaws between two minnow species over ontogeny.

This study compares sand shiner (Notropis stramineus) and silverjaw (Ericymba buccata) minnows, in terms of the morphological shape changes of the upper, lower, and pharyngeal jaws over ontogeny. These two species of minnows initially feed on midge larvae and undergo an ontogenic prey shift. The traditional morphometrics measured-total length, snout-to-vent length, eye diameter, premaxilla length, lower jaw length, gape-were regressed onto total length to test for allometry. Digital pictures were processed with tpsDig and further analyzed with MorphoJ utilizing a regular geometric morphometrics procedure using principle component analyses. We examined gut contents for 16 fish of each species. For the silverjaw minnows, we found all jaw variables to exhibit positive allometric growth with increasing total length, while most of the jaw variables for the sand shiner exhibited negative allometric growth with increasing total length. This correlates with an ontogenic prey shift for both species. Sand shiner minnows have been found to be more omnivorous, feeding on algae later in life, while silverjaw minnows undergo a prey shift to larger invertebrates. These species lack oral dentition causing an increased reliance on the pharyngeal apparatus. Principle component analyses revealed elongation of pharyngeal jaw elements in the silverjaw minnows and a relative shortening and bulking of pharyngeal jaws in the sand shiner minnows. The ontogenic dietary shifts observed in these two species provide possible explanation for the morphological changes over ontogeny in jaw elements, which are likely enabling these species to occupy the same habitat with little niche overlap.

Morphological Characterization of Two Fresh Water Eels Monopterus cuchia (Hamilton, 1822) and Ophisternon bengalense (McClelland, 1844)

Morphometric and meristic characters and truss measurements of 32 Monopterus cuchia, and of 17 Ophisternon bengalense were compared to know the population status of two fresh water eels of Bangladesh. The mean numbers of line below head were significantly different between two species. Significant differences were observed in 11 morphometric characters: Pre dorsal length (PDL), Post dorsal length (PoDL), Post anal length (PoAL), Head length (HL), Snout length (SnL), Upper jaw length (UJL), Lower jaw length (LJL), Head width (HW), Pre orbital length (PrOrL), Least body diameter (LBD) and Highest body diameter (HBD) and one truss measurement (3-5) between two species in varying degrees. For both morphometric and landmark measurements, the first and second DF (discriminant function) accounted 64.8% and 33.2% of among group variability, explaining 98% of total group variability. M. cuchia collected from Mymensingh and from Dinajpur constructed one sub-cluster and O. bengalense collected from Sathkhira and from Bagerhat constructed another sub-cluster based on the Distance of squared Euclidean dissimilarity. A correct classification of individuals into their original population from leave-one-out-classification varied between 93.3% and 94.1% by discriminant analysis. The results of the present study suggested that there was limited intermingling among populations and the populations of the species were separated from one another.J. Environ. Sci. & Natural Resources, 9(1): 127-137 2016

Changing Population of Aphidius colemani in Relation to Environmental Factors

Morphometric and meristic characters and truss measurements of 32 Monopterus cuchia, and of 17 Ophisternon bengalense were compared to know the population status of two fresh water eels of Bangladesh. The mean numbers of line below head were significantly different between two species. Significant differences were observed in 11 morphometric characters: Pre dorsal length (PDL), Post dorsal length (PoDL), Post anal length (PoAL), Head length (HL), Snout length (SnL), Upper jaw length (UJL), Lower jaw length (LJL), Head width (HW), Pre orbital length (PrOrL), Least body diameter (LBD) and Highest body diameter (HBD) and one truss measurement (3-5) between two species in varying degrees. For both morphometric and landmark measurements, the first and second DF (discriminant function) accounted 64.8% and 33.2% of among group variability, explaining 98% of total group variability. M. cuchia collected from Mymensingh and from Dinajpur constructed one sub-cluster and O. bengalense collected from Sathkhira and from Bagerhat constructed another sub-cluster based on the Distance of squared Euclidean dissimilarity. A correct classification of individuals into their original population from leave-one-out-classification varied between 93.3% and 94.1% by discriminant analysis. The results of the present study suggested that there was limited intermingling among populations and the populations of the species were separated from one another.J. Environ. Sci. & Natural Resources, 9(1): 139-141 2016

A new species of anchovy, Encrasicholina macrocephala (Clupeiformes:Engraulidae), from the northwestern Indian Ocean.

A new species of anchovy, Encrasicholina macrocephala, is described on the basis of 17 specimens collected from the Red Sea and the Arabian Sea. The species is closely related to E. devisi in that both species have three unbranched rays in the dorsal and anal fins, and a long upper jaw (posterior tip extending beyond posterior margin of preopercle). However, the new species is distinguished from E. devisi in having lower counts of total pectoral-fin rays (11-14 vs. 13-15) and pseudobranchial filaments (15-18 vs. 18-22), longer head length (29.5-31.7% of standard length vs. 25.4-28.9% in the latter), upper-jaw length (21.3-23.5% vs. 14.6-21.3%), and lower-jaw length (19.5-21.2% vs. 14.2-19.5%), and a shorter distance between the dorsal-fin origin to the pectoral-fin insertion (83.2-95.2% of head length vs. 97.6-126.1%).

Under pressure: morphological and ecological correlates of bite force in the rock-dwelling lizardsOuroborus cataphractusandKarusasaurus polyzonus(Squamata: Cordylidae)

Rock-dwelling lizards are hypothesized to be highly constrained in the evolution of head morphology and, consequently, bite force. Because the ability to generate a high bite force might be advantageous for a species' dietary ecology, morphological changes in head configuration that allow individuals to maintain or improve their bite force under the constraint of crevice-dwelling behaviour are to be expected. The present study addressed this issue by examining head morphology, bite force, and a number of dietary traits in the rock-dwelling cordylid lizards Ouroborus cataphractus and Karusasaurus polyzonus. The results obtained show that O. cataphractus has a larger head and higher bite force than K. polyzonus. In K. polyzonus, head width, lower jaw length, and jaw closing-in lever are the best predictors of bite force, whereas head height is the main determinant of bite force in O. cataphractus. Although the observed difference in bite force between the species does not appear to be related to dietary patterns or prey handling, the prey spectrum available for intake was greater in O. cataphractus compared to K. polyzonus. We discuss the influence of interspecific differences in anti-predator morphology on head morphology and bite force in these rock-dwelling species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 823–833.

Morphometric characters of Nile tilapia (Oreochromis niloticus) in Thailand

The present study is conducted to describe the morphometric characteristics of a Thailand strain of Oreochromis niloticus . The total length of the observed fish ranged from 7.96 - 17.36 cm. Body measurement and proportions are extensively used for identification of this species. The following 18 measurements are determined for each fish: Total length (TL); Standard length (SL); Body depth (BD); Pre-dorsal length (PDL); Pre-pectoral length (PPCL); Pre-pelvic length (PPVL); Pre-anal length (PAL); Depth of caudal peduncle (DCP); Length of caudal peduncle (LCP); Head length (HL); Eye diameter (ED); Snout length (SNL); Upper jaw length (UJL); Lower jaw length (LJL); Caudal fin length (CFL); Pectoral fin length (PFL); Length of dorsal fin base (LDFB); Length of anal fin base (LAFB). The rate of growth of different morphological body parts of the fish in relation to its total length is studied. Additionally, the total length and body weight relationship is found to be a straight line in logarithmic scale expressed as Log BW = 3.026 Log TL - 1.839. The value of regression co-efficient obtained for the length-weight relationship is 3.026. This finding suggests that selection for growth using this equation is a good alternative for measuring weight in the field, when accurate weighing balances are not available. Hence, the present study provides the information of the various body parts measurements of Tilapia and establishes mathematical equations relating to these various morphometric relationships which can be utilized for the conversion of one measurement into another. doi: 10.14456/WJST.2014.76