river drainage
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Zootaxa ◽  
2021 ◽  
Vol 5081 (4) ◽  
pp. 551-565
Author(s):  
YENGKHOM CHINGLEMBA ◽  
YUMNAM RAMESHORI ◽  
WAIKHOM VISHWANATH

Mustura taretensis, a new nemacheilid loach, is described from the Taret River, a tributary of the Yu River, Chindwin River drainage, Manipur, India. The new species is distinguished from all its congeners by a unique combination of the following characters: body with 12–13 irregular dark-brown blotches or bars on flank, alternating with 11–16 irregular dark-brown saddles on the back; dorsum of head with a distinctly visible rhomboid dark-brown mark encircling a pale oval area on the nape; dorsal fin with 9½­ or 10½ branched rays; lateral line complete; a well-developed free posterior chamber of air bladder, the halves of air bladder capsules connected by a manubrium; poorly developed processus dentiformis; suborbital flap present in males; and body depth 12.8–16.0 % SL. The generic status of Mustura chindwinensis, M. dikrongensis, M. tigrina and M. tuivaiensis are also discussed in the paper.  


2021 ◽  
Vol 13 (2) ◽  
pp. 32
Author(s):  
Eric Clausen

A new Cenozoic geologic and glacial history paradigm (new paradigm) describes massive and prolonged continental ice sheet meltwater floods that eroded the Colorado Royal Gorge area and surrounding regions and which were diverted in east, northeast, and even north directions as uplift of a thick ice sheet created deep “hole” rim gradually occurred (the thick ice sheet was located where North American ice sheets are usually recognized to have existed). A deep “hole” rim segment followed what is now the northern and central Colorado east-west continental divide southward to the Arkansas River headwaters area and then continued south along the Sangre de Cristo Mountains crestline to at least the Purgatoire River-Canadian River drainage divide and may have continued east from that point along a less well-defined zone beginning with what is now the Purgatoire River-Canadian River drainage divide. Diverging and converging valley complexes, barbed tributaries, and Arkansas River and other drainage route direction changes (easily seen on United States Geological Survey detailed topographic maps) are interpreted to have developed as the south-oriented floodwaters first flowed across the rising deep “hole” rim to reach the south- and southeast-oriented Rio Grande River drainage basin and were subsequently blocked by deep “hole” rim uplift and diverted to flow in east, northeast, and north directions. The accepted Cenozoic geologic and glacial history paradigm (accepted paradigm) has to date been unable to satisfactorily explain the detailed topographic map drainage system and erosional landform evidence and the new and accepted paradigms are incommensurable and lead to quite different Cenozoic geologic and glacial histories.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3233
Author(s):  
Kyle J. Hartman ◽  
David I. Wellman ◽  
Joseph W. Kingsbury ◽  
Daniel A. Cincotta ◽  
Janet L. Clayton ◽  
...  

Inland waters provide valuable ecosystem goods and services and are intrinsically linked to downstream coastal areas. Water quality impairments that lead to harmful algal blooms damage valuable commercial and recreational fishing economies, threaten food security, and damage already declining native species. Prymnesium parvum is a brackish water golden alga that can survive in salinities less than 1 ppm and when it blooms it can create toxins that kill aquatic life. Blooms have been documented globally including 23 U.S. states. We report a case study of an aquatic life kill associated with P. parvum in Dunkard Creek (WV-PA, USA), in the Ohio River Drainage. We document the immediate impact to aquatic life and responses of the aquatic community ten years post-kill. Most fish species returned within a year. Excellent connectivity to unimpacted tributaries and a river downstream likely aided the reestablishment of most species, although some had not reached pre-kill abundances after ten years. Mussel taxa did not recover despite significant efforts to relocate adult mussels and stocking of host fish inoculated with glochidia; probably due to other water quality impairments. Given the potential for lateral transport of P. parvum via industry and natural vectors we conducted an ecological risk assessment mapping the spatial extent of U.S. waters that could be threatened by golden algae colonization and blooms using a national water quality database and a state database. Overall, about 4.5% of lotic systems appeared to have some level of risk of harboring P. parvum, making them at risk for potential golden algae blooms in the face of increasing salinization and eutrophication of freshwaters.


2021 ◽  
Vol 13 (21) ◽  
pp. 4393
Author(s):  
Ana Carolina Freitas Xavier ◽  
Anderson Paulo Rudke ◽  
Edivaldo Afonso de Oliveira Serrão ◽  
Paulo Miguel de Bodas Terassi ◽  
Paulo Rógenes Monteiro Pontes

Satellite precipitation estimates are used as an alternative or as a supplement to the records of the in situ stations. Although some satellite precipitation products have reasonably consistent time series, they are often limited to specific geographic areas. The main objective of this study was to evaluate CHIRPS version 2, MSWEP version 2, and PERSIANN-CDR, compared to gridBR, as daily mean and extreme inputs represented on a monthly scale and their respective seasonal trends of rainfall in the Mearim River Drainage Basin (MDB), Maranhão state, Brazil. Estimates of errors were calculated (relative error, pbias; root mean square error, RMSE, and Willmott concordance index, d), and the chances of precipitation were estimated by remote sensing (RES). In addition, trends in precipitation were estimated by the two-sample Mann–Kendall test. Given the overall performance, the best products for estimating monthly mean daily rainfall in the MDB are CHIRPS and PERSIANN-CDR, especially for rainy months (December to May). For daily extremes on the monthly scale, the best RES is PERSIANN-CDR. There is no general agreement between gridBR and RES methods for the trend signal, even a nonsignificant one, much less a significant one. The use of MSWEP for the MDB region is discouraged by this study because it overestimates monthly averages and extremes. Finally, studies of this kind in drainage basins are essential to improve the information generated for managing territories and developing regionalized climate and hydrological models.


Zootaxa ◽  
2021 ◽  
Vol 5052 (3) ◽  
pp. 380-394
Author(s):  
MAZAHER ZAMANI-FARADONBE ◽  
E. ZHANG ◽  
YAZDAN KEIVANY

Garra hormuzensis, new species, is described from the Kol River drainage. It is distinguished from its congeners in the Iranian part of the Persian Gulf basin by having 7½ branched dorsal-fin rays, usually 9+8 branched caudal-fin rays, the breast, belly and back in front of the dorsal-fin origin covered by scales, and a free lateral and posterior margins of the gular disc. It is further characterised by having a minimum K2P distance of 1.16% to G. mondica in the mtDNA COI barcode region.  


2021 ◽  
pp. 1-18
Author(s):  
Anthony M. Krus ◽  
John D. Richards ◽  
Robert J. Jeske

The Middle Mississippian component at Aztalan was a mixed, Late Woodland / Mississippian occupation sited within a heavily fortified habitation and mound center that is located on a tributary of the Rock River in Wisconsin. It represents the northernmost large Cahokian-related village recorded. The Oneota Lake Koshkonong Locality of the Rock River drainage is located approximately 20 km south of Aztalan, and it consists of a 25 km2 area along the northwest shore with a small cluster of habitation settlements. Sixty-eight radiocarbon measurements have been obtained from Aztalan, and 52 from Oneota settlements in the Lake Koshkonong Locality. We discuss how to best interpret this dataset, and we use Bayesian chronological modeling to analyze these dates. The results suggest that (1) Aztalan's Late Woodland (Kekoskee phase) occupation began in the AD 900s or early AD 1000s, (2) Aztalan's Mississippian occupation ceased in the AD 1200s, (3) Oneota occupations at Lake Koshkonong began after AD 1050 and were established by the AD 1200s, and (4) Oneota occupations at Lake Koshkonong continued after Aztalan's Mississippian abandonment until at least the late AD 1300s. Additionally, the results demonstrate that Aztalan was fortified with a palisade with bastions for much of the Mississippian occupation, suggesting a contested presence in a multiethnic landscape.


Zootaxa ◽  
2021 ◽  
Vol 5048 (2) ◽  
pp. 265-278
Author(s):  
GOLNAZ SAYYADZADEH ◽  
HAMID REZA ESMAEILI

Recognizing and defining a species has been a controversial concern for a long time. To define the variation and the limitation between different species, especially closely related taxa in a complex species group, several concepts have been proposed which may lead to different taxonomic decisions. When a taxonomist studies a specific taxon, she/he should adopt a species concept and provide a species limitation to define the studied taxa. Garra population from the Kol River drainage, Persian Gulf basin has already been considered as Garra sp., based on molecular data, and to date no taxonomic decision has been made to provide a specific name for it. The Kol population presents several morphological characters that distinguish it from congeners: fully scaled breast; 7–8 ½ branched dorsal-fin rays; caudal fin with 16–17 branched rays and well-developed mental disc with free lateral and posterior margins. It is also distinguished from all other congeners in the Garra rufa group in Iran, by having two fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region. Furthermore, the Kol population demonstrates some distinct osteological characteristics in comparison to its closest species G. mondica. Based on the integrative molecular phylogenetic and species delimitation analyses, and morphological, osteological and distribution range data presented here, we think that the Kol River population merits formal description and can be considered as a distinct taxonomic unit (species).  


2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Matthew Afolabi ◽  
Olayinka Ogunkoya

Inselbergs’ spatial distribution is the primary focus of this study carried out in Igbajo District of Western Nigeria. Additionally, a common hypothesis that spatial distribution of inselbergs is informed by the differing modes of evolution of the landforms was also examined. Inselbergs are defined as points on the topographic sheet and satellite terrain elevation data and are thereafter subjected to point pattern analysis. Two point pattern analyses: Poisson Probability Distribution (PPD) and Nearest Neighbour Analysis (NNA) are employed to determine the pattern of inselberg distribution over space. Additional analysis focused on the relationship between regional river drainage and inselbergs’ spatial distribution. Findings from the study confirmed that inselberg form a clustered distribution. The PPD results suggest that the observed distribution of inselbergs has a statistically significant difference from the expected pattern generated by the random process (c2 test statistic = 49.82 >  =12.59 (α= 0.05) and 16.81 (α= 0.01). Similarly, the NNA with a R < 1 (Nearest Neighbour Ratio, R = 0.92) and p-value = -2.52, also indicated a clustered distribution. Analysis of river drainage pattern similarly revealed a cluster of high rising landforms situated in the centre of the regional watershed. It is concluded that inselberg distribution in the study area is clustered although the observed pattern does not necessarily validate or invalidate the alternative evolutionary theories.


2021 ◽  
pp. 106-134
Author(s):  
Cynthia E. Dott ◽  
Gary L. Gianniny ◽  
David A. Gonzales

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