Zoology


https://sites.google.com/a/gauhati.ac.in/research/zoology/#rdc30082019 Embryonic development of pipefish

https://sites.google.com/a/gauhati.ac.in/research/zoology/#bk01072019 Killing the killers

https://sites.google.com/a/gauhati.ac.in/research/zoology/#hc01022019 Schistura rebuw - a new species of fish

Embryonic development of a pipefish

Dandadhar Sarma and collaborators report about a first comprehensive embryonic development of an endangered freshwater pipefish endemic to the region, which may help conserve such species. This work is published in the Journal of Applied Ichthyology.



Authors
Anu Saikia, Minakshi Kalita, Hrishikesh Choudhury, Lalit K Tyagi1, Dandadhar Sarma, and Kuldeep K Lal1
from other institutions

Abstract
The present study provides the first comprehensive embryonic development of the freshwater Syngnathid fish species, Microphis deocata (Hamilton), a Near Threatened pipefish endemic to the Brahmaputra River drainage in Northeast India and Bangladesh. Microphis deocata is a Gastrophori species as the males develop an abdominal brood pouch. Mature individuals were collected and maintained in well‐aerated aquaria under controlled conditions to induce natural spawning. The number of eggs within the males' brood pouch ranged from 17 to 22 (for n = 10), measuring 0.7–1.0 mm in diameter. A total of 10 developmental stages could be recognised under four developmental periods namely, early embryogenesis, eye development, snout formation and juvenile. However, sensitivity, and therefore mortality, while handling of this species restricted the study from reporting the exact time intervals for stages following the blastodisc formation ~48 hr post fertilisation. A newborn larvae measures ~14 mm and is free‐swimming with distinct dorsal fin (with 31–32 rays) and a sector‐shaped caudal fin (with 8–9 rays). The study aims to provide baseline information on the embryology of M. deocata in culture condition which will be helpful for future studies on conservation biology, population status and management of this species.

Journal Reference
https://sites.google.com/a/gauhati.ac.in/research/zoology/#top 
 



A concoction of oils for the killer mosquitoes 

Bulbuli Khanikor and her scholars test a concoction of plant-based oils to target the Aedes aegypti mosquitoes, which is the primary cause of diseases like dengue fever, chikungunya, etc. This research work is published in Nature Scientific Reports.


Authors
Riju Sarma, Kamal Adhikari, Sudarshana Mahanta, and Bulbuli Khanikor

Abstract
Twenty-eight combinations of plant essential oil-based terpene compounds were prepared and tested against larval and adult stages of Aedes aegypti. Initially five plant essential oils (EOs) were assessed for their larvicidal and adulticidal efficacy and two of their major compounds from each EO were identified from GC-MS results. Identified major compounds namely Diallyldisulfide, Diallyltrisulfide, Carvone, Limonene, Eugenol, Methyl Eugenol, Eucalyptol, Eudesmol and α-pinene were purchased and tested individually against Aedes aegypti. Binary combinations of these compounds were then prepared using sub-lethal doses, tested and their synergistic and antagonistic effects were determined. The best larvicidal compositions and the best adulticidal composition of terpene compounds and terpene plus commercial mosquitocidal compounds were highlighted based on small scale and large scale treatments on Aedes aegypti.

Schistura rebuw - a new species of stone loach

Hrishikesh Choudhury and his colleagues have reported the finding of a new fish species from the Kameng River of lower Arunachal Pradesh. This finding is published in the journal Zootaxa


Authors
Hrishikesh Choudhury, Abhinit Dey, Ratul Ch Bharali1, Dandadhar Sarma, and Waikhom Vishwanath1
1 from other institutions

Abstract
Schistura rebuw, new species, is described from the Kameng River, a north-bank tributary of the Brahmaputra, Arunachal Pradesh, India. The new species is easily distinguished from all known congeners in the Brahmaputra basin by its unique sexual dimorphism, specifically a suborbital slit in adult females, and a suborbital flap in adult males; and a colour pattern of 10–11 blackish bars on a greyish-beige body, the pre-dorsal bars mostly broken or incomplete, coalescing dorsally in a more or less alternate fashion.

Journal Reference
https://sites.google.com/a/gauhati.ac.in/research/zoology/#top