Morphometric and meristic characteristics of an endemic Lagusia micracanthus Bleeker, 1860 in the rivers of Maros and Wallanae Cenrana Watersheds

Pirik (Lagusia micracanthus Bleeker, 1860) is one of endemic fishes in Sulawesi. Morphometric and meristic information of Pirik population in various habitats are unknown. The present study aimed to determine the morphometric and meristic variation of Pirik in Maros and Wallanae Cenrana watersheds. Sampling collection was carried out monthly from May 2018 to April 2019 in the Maros watershed, namely Pattunuang River (M1), Bantimurung River (M2), Pucak River (M3); and in Wallanae Cenrana watershed particularly in Camba River (W1), Sanrego River (W2), and Ompo River (W3). Morphometric measurements consisted of 31 characters and meristic measurements consisted of 10 characters. Morphometric data was standardized by dividing all morphometric characters by standard length (SL). Analysis of variance (ANOVA) and discriminant analysis (Discriminant Function Analysis) were applied for data analysis. The results showed that the Pirik taken from rivers in the Maros and Wallanae Cenrana watershed are two different population groups. There are 12 distinguishing morphometric features for Pirik of the Maros and Wallanae Cenrana watershed, i.e. TL (total length), SL (standard length), BDdSA (body depth-dorsal fin origin), HL (head length), Jlup (upper-jaw length), PAfL (pre-anal fin length), ABL (Anal fin base length), PelRL (pelvic ray length), AFRL (anal fin ray length), CPL (caudal peduncle length), CLLup (upper caudal lobe length) and CLLmid (mid-caudal length). There is no significant difference of meristic characters of Pirik obtained from the Maros and Wallanae Cenraa watersheds.

The Anadromous Hickory Shad (Clupeiformes: Clupeidae, Alosa mediocris [Mitchill 1814]): Morphometric and Meristic Variation

The anadromous Hickory Shad Alosa mediocris (Mitchill, 1814) (Clupeiformes: Clupeidae) is reviewed, specifically regarding morphometric and meristic variation. Despite its long history as recognized species, few descriptions of Hickory Shad morphometric and meristic characters exist in the literature. Most authors of the historic literature have failed to provide capture location for specimens, analyze large numbers of Hickory Shad, or document how morphometric and meristic characters of the species vary spatially. To address this information gap, a total of 717 mature Hickory Shad were collected from 23 different locations in Maryland, Delaware, Virginia, North Carolina, South Carolina, Georgia, and Florida using electroshocking, gill net, or rod and reel. All specimens were frozen, thawed, and 17 morphometric characters and four meristic characters were examined; a random subset (n = 463) were analyzed for an additional four meristic counts of gill rakers. Overall specimens ranged from 206-389 mm SL with a mean + SD of 278.41 + 27.69 mm, 232-435 mm FL with a mean of 310.98 + 30.35 mm, and 272-508 mm TL with a mean of 365.62 + 35.52 mm. The linear relationships between FL and TL, and FL and SL, were investigated and found to be: TL = 1.169*FL + 1.660 (n=705, r2=0.995) and SL = 0.909*FL - 4.274 (n=717, r2=0.992). Substantial differences in character means for many morphometric measurements were found between male and female specimens, suggesting strong sexual dimorphisms relating to shape. However, meristic characters did not show differences in character means by sex. No one morphometric measurement could distinguish Hickory Shad from other morphologically similar clupeids, but the meristic count of gill rakers on the lower limb of the first arch were important to separate Hickory Shad (19-22) from American Shad A. sapidissima (Wilson, 1811), Alewife A. pseudoharengus (Wilson, 1811), and Blueback Herring A. aestivalis (Mitchill, 1814).

Morphometric and meristic variation in the Atlantic chub mackerel Scomber colias Gmelin, 1789 from the Moroccan coast

Morphometric and meristic characters were used to study the variability between Scomber colias Gmelin, 1789 sampled from five locations in the Moroccan Atlantic coast. Eighteen morphometric measurements were taken using the image processing program, Image j along with seven meristic characters. Univariate analysis of variance (ANOVA) performed by Tukey HSD post-hoc test showed significant differences for 14 standard morphometric measurements. In principal component analysis (PCA),PC1 was resolved as general size and PC2 was resolved as shape differences. Discriminant analysis indicated the existence of four morphometric groups of S. colias with minor overlapping, which suggested that there is a self-recruiting population. The proportion of correctly classified Sidi Ifni (SDF) sample to their original group was 96% and showed clear separation from other groups. We concluded that Sidi Ifni samples are morphologically distinct from S. colias of the other four localities which could be attributed to genetic bias or environmental factors.

Variation in morphometric and meristic traits of Aspidoparia morar from Brahmaputra and Barak Rivers of Assam, India

The minor carp, Aspidoparia morar is a benthopelagic fish belonging to the sub-family Danioninae under the family Cyprinidae. It has emerged as the single most dominant species in the river Brahmaputra in Assam. In the present study, 240 specimens were collected from Guwahati and Tezpur in the Brahmaputra River and Silchar in the Barak River to investigate the morphometric and meristic variation among the populations. For this a total of 20 morphometric traits and 11 meristic traits were studied. The mean lengths for most of the morphometric traits were higher for the Barak River except eye diameter, inter orbital length and anal fin length which were significantly higher on the Brahmaputra River, while the post orbital length and pelvic fin length were found to be almost equal. The regressions of standard length with all the morphometric traits except pelvic fin length, pelvic fin base, pectoral fin length, dorsal fin length, anal fin length, pre orbital length, post orbital length, inter orbital length and eye diameter showed significant variation between the rivers. Two meristic traits viz. branched rays in anal fin and gill rakers on the first gill arch also showed significant variation in the samples of the rivers.

Meristic variation in males of the hydrothermal vent octopus,Muusoctopus hydrothermalis(Cephalopoda: Octopodidae)

Intraspecific variation in characters such as arm sucker and gill lamellae counts in octopodids is yet to be thoroughly investigated, potentially hampering our ability to recognize species. In this study, data from 13 specimens ofMuusoctopus hydrothermaliscollected at four hydrothermal vents on the East Pacific Rise between 8°38′N and 12°48′N are considered. Although the northern and southern octopuses differ minimally in size, mean sucker count by arm in the northern group is 11.7 to 22.8% higher than it is in the southern group; in addition these octopuses typically have an additional gill lamella and bulkier funnel organs. The arms of each individual carry a different number of suckers. The difference is significant on nonadjacent arms, a pattern that merits examination in a broader taxonomic context. Why these differences exist among conspecifics remains unknown, the incidence of parasitic copepods is not different between the groups and the between-group variation in arm suckers seen here compares well with a previous report of variation among 18 specimens from the type locality. Increases in meristic characters (counts) in fish are attributed to lower temperatures during embryonic development following Jordan's rule. Northern and southern vents offer the octopuses a wide temperature range, but vent fluid chemistry differs. Northern vent fluids may be more toxic; if so, developing octopus embryos may survive only minimal vent fluid exposure and therefore develop at low temperatures. At the less toxic southern vents, eggs may survive greater exposure to vent fluids and thus develop at higher temperatures.