Problems of compensative fisheries: increasing the adaptive potential of broad whitefish Coregonus nasus (Pallas) in early ontogenesis by weak magnetic fields. 1. Morphometric analysis

Author(s):  
Alexander Germanovich Selyukov ◽  
Ekaterina Vladimirovna Efremova ◽  
Svetlana Aleksandrovna Selyukova ◽  
Leonid Alexandrovich Shuman

The article presents the results of a production experiment with the embryos of Coregonus nasus, delivered at the Sobsk fish hatchery (settlement Kharp, YaNAO). The plant is taking compensatory measures to restore the number of valuable species of whitefishes in the Ob river basin. The purpose of our study was to increase the biological potential of juvenile broad whitefish for their subsequent release to the Ob river. At the last stage of the embryonic period, the embryos were treated with ultra-weak pulsed magnetic fields for several days. In the postembryonic period, the control and experimental juveniles of broad whitefish were fixed for subsequent morphometric and cytological-histological analysis. After conducting a morphometric analysis, we found that already at the early stages of the postembryonic period, the experimental larvae and fry exceeded the control ones in most parameters. Later, these differences persisted. At the same time, the juveniles of the experimental batch showed, as a rule, less variability of morphological characters. Also, the weight of the experimental fry before release to the Ob significantly exceeded the weight of the control fry. We calculated the degree of correlation of morphometric characters in juvenile broad whitefish of both parties in the process of rearing and found that during the first month the correlation of most parameters in the experimental juveniles was lower than in the control. However, with further development, the degree of relationship between the parameters in juveniles in the experiment increased and reached it in the control. Later, the allometric growth of the experimental juveniles began, which caused a decrease in the connection between some characters. We are discussing the features of the development of experimental juvenile fish; activation of its natural mechanisms of autorehabilitation by using weak physical factors. We explain the reasons for the stable, but insignificant differences between the experimental fish fry over the control treatment with an ultra-weak pulsed magnetic field at the last stages of embryogenesis, when the main organ systems are already formed. We conclude that this approach is advisable, starting with fertilization and early embryogenesis.

Crustaceana ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1495-1504 ◽  
Author(s):  
Rajan Kumar ◽  
Shikha Rahangdale ◽  
Subal Kumar Roul

Abstract Albuneid crabs are specialized and active sand-burrowing organisms. Despite their substantial diversity, their ability to avoid fishing gear leads to “under collection” and a discontinuous record of distribution. The present study documents the first distributional record of Albunea occulta Boyko, 2002 from the Bay of Bengal, eastern Indian Ocean. Albunea thurstoni Henderson, 1893 is also recorded for the first time from the area, i.e., from the Gulf of Mannar, southwestern Bay of Bengal. This study further reports variation in morphological characters, especially in the carapace grooves (CG) from previous records and across specimens from different regions. Morphometric characters were found useful in species discrimination, which is explained as well.


2016 ◽  
Vol 36 (2) ◽  
pp. 141-160 ◽  
Author(s):  
Sofwan Noerwidi

In 2014 there was found two "enigmatic" specimens of mandible, which named as Semedo 3417 and 3418. Both mandibles are morphologically similar but twice bigger than common primate’s jaw. In this research, we use morphology and morphometric analysis to determine the species identity and taxonomic position of those specimens. For comparison study we use some samples from Homo erectus (Java and China), Gigantopithecus (blacki and bilaspurensis), Australopithecines (robust and gracile). Based on morphology and morphometric characters on the mandible and teeth, it is concluded that Semedo specimen tends to be close to Gigantopithecus blacki. The discoveries of Gigantopithecus fossil in Java has implication on some research problem, especially regarding the adaptation pattern of this species which known only found at high latitudes environment. Furthermore this discovery has reinforced the perspective that tropical environment has a very high biodiversity, particularly on primate fossils.


Zootaxa ◽  
2018 ◽  
Vol 4442 (4) ◽  
pp. 551 ◽  
Author(s):  
FLÁVIO KULAIF UBAID ◽  
LUÍS FABIO SILVEIRA ◽  
CESAR A. B. MEDOLAGO ◽  
THIAGO V. V. COSTA ◽  
MERCIVAL ROBERTO FRANCISCO ◽  
...  

Seed-finches are small-sized Neotropical granivorous birds characterized by extremely strong and thick beaks. Among these birds, the Great-billed Seed-Finch Sporophila maximiliani has been selectively and intensively trapped to the extent that has become one of the most endangered bird species in South America, yet its taxonomy remains complex and controversial. Two subspecies have been recognized: S. m. maximiliani (Cabanis, 1851), mainly from the Cerrado of central South America, and S. m. parkesi Olson (= Oryzoborus m. magnirostris), from northeastern South America. Originally, S. m. parkesi was diagnosed as being larger than the Large-billed Seed-Finch, S. c. crassirostris (Gmelin, 1789), but proper comparisons with S. m. maximiliani, which is larger than S. c. crassirostris, were never performed. Here we provide a review of the taxonomic and nomenclatural history of S. maximiliani, reevaluate the validity and taxonomic status of the subspecies based on morphological characters, and significantly revise its geographic distribution. Analyses based on plumage patterns and a Principal Component Analysis of morphometric characters indicated that S. m. parkesi is most appropriately treated as a synonym of the nominate taxon, which results in a monotypic S. maximiliani comprising two disjunct populations. Further, we conducted systematic searches for S. maximiliani in Brazil, in an attempt to obtain natural history information. After more than 6,000 hours of fieldwork in 45 areas of potential and historical occurrence, S. maximiliani was located only in two sites, in marshy environments called veredas, confirming the critical conservation status of this species, at least in Brazil. We discuss the conservation potential for, and the problems involved with, captive breeding of S. maximiliani for reintroduction into the wild. 


Zootaxa ◽  
2009 ◽  
Vol 2110 (1) ◽  
pp. 41-57 ◽  
Author(s):  
WILLIAM T. WHITE ◽  
LEONARD J. V. COMPAGNO ◽  
DHARMADI _

A new species of the genus Hemitriakis Herre, 1923 (Family Triakidae, Order Carcharhiniformes), is described from off the islands of Bali and Lombok in eastern Indonesia. Hemitriakis indroyonoi is separable from the other congeners, H. abdita, H. complicofasciata, H. falcata, H. japanica and H. leucoperiptera, by a combination of vertebral counts, morphometric characters, and juvenile coloration. H. indroyonoi is most similar to H. falcata from northwestern Australia but differs in juvenile coloration, some meristic and morphological characters, size and cranial morphology. The new species is allopatric to other members of this genus.


2016 ◽  
Vol 85 (4) ◽  
pp. 361-386 ◽  
Author(s):  
Jonas Keiler ◽  
Stefan Richter ◽  
Christian S. Wirkner

The Southern Australian crustacean species Lomis hirta (Lomisoidea: Lomisidae) is a representative of one of the three anomuran taxa which obtained their crab-like habitus independently from each other. This process, the evolutionary transformation into a crab-like form, is termed carcinization. To shed light on the morphological changes which took place during carcinization and to investigate structural dependence (coherence) between external and internal morphological characters, we studied L. hirta and representatives of its putatively most closely related taxa, Aegla cholchol (Aegloidea: Aeglidae) and Kiwa puravida (Chirostyloidea: Kiwaidae). External and internal anatomy was studied using microcomputertomography and computer-aided 3D reconstruction. A. cholchol and K. puravida belong to equally exceptional lineages: Aegla is endemic to South America and lives in freshwater habitats; Kiwa is a deep sea dweller associated to chemosynthetic bacteria found in methane seeps or hydrothermal vents. On the basis of recent cladistic analyses we reconstruct the anatomical ground pattern of the squat lobster-like last common ancestor of the three taxa and trace the morphological transformations that affected inner and outer morphology in the recent forms. Our results show, among other things, that the pleon in Lomis underwent drastic modifications in the context of carcinization, including a reduction of the muscular portion leaving more room for the hepatopancreas and gonads, and a narrowing of the pleonal ganglia which became shifted anteriorly into the cephalothorax and attached to the cephalothoracic ganglion. We interpret these anatomical changes in Lomis to have come about because of the loss of the caridoid escape reaction, which in turn was a direct consequence of the evolution of a strongly bent pleon as part of the crab-like habitus, and of a hidden lifestyle.


1989 ◽  
Vol 67 (10) ◽  
pp. 2376-2383 ◽  
Author(s):  
Clifford W. Zeyl ◽  
Leslie A. Lowcock

Six morphometric characters and one meristic character were measured on 96 adult and 88 juvenile Ambystoma from Kelleys Island, where extensive hybridization involves three species. Canonical variates, discriminant functions, and size-constrained principal components analyses showed that A. laterale (represented only in hybrids on Kelleys Island), A. texanum, A. tigrinum, and A. laterale–texanum–tigrinum are distinguishable from each other and from a complex of hybrids involving A. texanum and A. laterale. Within the latter complex, different ploidies are not distinct morphologically. Introgression may explain isolated atypical individuals. Adults differ from juveniles in both size and shape, demonstrating allometry.


1989 ◽  
Vol 121 (12) ◽  
pp. 1103-1109 ◽  
Author(s):  
Jeffrey A. Lockwood

AbstractMorphometric analysis of 16 body measurements of migratory and solitary Melanoplus sanguinipes (F.) and M. spretus (Walsh) was used to determine if M. spretus was, in fact, the migratory phase of M. sanguinipes. Migratory M. sanguinipes was found to be more similar to its own solitary phase than to M. spretus. Melanoplus spretus resembled migratory M. sanguinipes, but in 14 comparisons M. spretus differed significantly from both solitary and migratory M. sanguinipes. Despite the potential for environmental variation obscuring differences in morphology, the divergent morphometric characters of M. spretus and the phases of M. sanguinipes appear to justify the status of M. spretus as a true species.


Zootaxa ◽  
2018 ◽  
Vol 4392 (2) ◽  
pp. 267 ◽  
Author(s):  
MARCELO KOVAČIĆ ◽  
FRANCESC ORDINES ◽  
ULRICH K. SCHLIEWEN

A new gobiid species, Buenia lombartei sp. nov. (Teleostei: Gobiidae) is described from the continental slope off the Balearic Islands, western Mediterranean. The Atlantic species Buenia jeffreysii (Günther, 1867) is redescribed and the first record of Buenia affinis Iljin, 1930 is reported for the islands. A key for the species of genus Buenia is provided. The new species can be distinguished from congeneric species by morphological characters: anterior oculoscapular canal semi-closed with pores σ, λ, κ, α, ρ and additional pores and open furrows; suborbital row c of 6 papillae; anal fin I/7-I/8; scales in lateral series 25-27; scales in transverse series 6; pectoral fin rays 18; the second spine of the first dorsal fin longest, backwards reaching to middle second dorsal fin in males when folded down; pelvic fin anterior membrane reduced to less than one sixth of spinous ray in midline depth; tongue well developed and bilobed and several morphometric characters. The new species is also characterized by its reduced colouration and unique depth range and occurrence on upper slope muddy bottoms. Contrary to this, only a small number of gobiid species in the Mediterranean reach beyond the circalittoral to the deep shelf, and just a few have records below the shelf break. Phylogenetic analysis of their mitochondrial COI sequence grouped the two specimens within the same clade as B. jeffreysii, but one apomorphic transversion diagnoses the B. lombartei subclade. A hypothesis about rapid speciation of B. lombartei as well as alternative hypotheses are discussed. During the Last Glacial Maximum, boreal fish species such as cold-water adapted gadids, now restricted to northwestern Europe, entered the Mediterranean. This may have also been the case of the boreal population of B. jeffreysii. At the end of the glacial period, increasingly warming Mediterranean waters might restricted B. jeffreysii to deeper coldwater mud habitats of the upper slope, where it finally adapted to bathyal conditions.  


1999 ◽  
Vol 12 (1) ◽  
pp. 117 ◽  
Author(s):  
L. W. Cayzer ◽  
M. D. Crisp ◽  
I. R. H. Telford

Bursariais an endemic Australian genus of mostlyspinescent, scruffy shrubs and trees, found in all but the most arid or alpineareas. Previous classifications include many infraspecific taxa and haveproved unworkable in eastern Australia. This paper presents a revision of thegenus. On the basis of phenetic analyses of morphometric characters thefollowing taxa are now recognised: B. calcicolaL.Cayzer, Crisp & I.Telford, B. incana Lindl.,B. longisepala Domin,B. occidentalis E.M.Benn.,B. reevesii L.Cayzer, Crisp & I.Telford,B. spinosa Cav. subsp. lasiophylla (E.M.Benn.) L.Cayzer, Crisp & I.Telford, B. spinosasubsp. spinosa and B. tenuifoliaF.M.Bail. Two are described as new(B. calcicola, B. reevesii), and one is changed in rank:B. spinosa subsp. lasiophylla(formerly B. lasiophylla E.M.Benn.). None of the otherinfraspecific taxa recognised previously is supported by our analyses.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9884
Author(s):  
Mariana D. Guilardi ◽  
Pablo Jayat ◽  
Marcelo Weksler ◽  
James L. Patton ◽  
Pablo Edmundo Ortiz ◽  
...  

The taxonomic history of Euryoryzomys legatus has been complex and controversial, being either included in the synonymy of other oryzomyine species or considered as a valid species, as in the most recent review of the genus. Previous phylogenetic analyses segregated E. legatus from E. russatus, its putative senior synonym, but recovered it nested within E. nitidus. A general lack of authoritative evaluation of morphological attributes, details of the chromosome complement, or other data types has hampered the ability to choose among alternative taxonomic hypotheses, and thus reach a general consensus for the status of the taxon. Herein we revisit the status of E. legatus using an integrated approach that includes: (1) a morphological review, especially centered on specimens from northwestern Argentina not examined previously, (2) comparative cytogenetics, and (3) phylogenetic reconstruction, using mitochondrial genes. Euryoryzomys legatus is morphologically and phylogenetically distinct from all other species-level taxa in the genus, but its 2n=80, FN=86 karyotype is shared with E. emmonsae, E. nitidus, and E. russatus. Several morphological and morphometric characters distinguish E. legatus from other species of Euryoryzomys, and we provide an amended diagnosis for the species. Morphological characters useful in distinguishing E. legatus from E. nitidus, its sister taxon following molecular analyses, include: larger overall size, dorsal fur with a strong yellowish brown to orange brown tinge, flanks and cheeks with an orange lateral line, ventral color grayish-white with pure white hairs present only on the chin, presence of a thin blackish eye-ring, tail bicolored, presence of an alisphenoid strut and a well-developed temporal and lambdoid crests in the skull, and a labial cingulum on M3. Molecular phylogenetic analyses recovered E. legatus as a monophyletic group with high support nested within a paraphyletic E. nitidus; genetic distances segregated members of both species, except for an exemplar of E. nitidus. Our integrated analyses reinforce E. legatus as a full species, but highlight that E. macconnelli, E. emmonsae, and E. nitidus each may be a species complex and worthy of systematic attention. Finally, we also evaluated the chromosome evolution of the genus within a phylogenetic context.


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