Redescription of Myxobolus rhinichthidis (Myxosporea) parasitizing Rhinichthys cataractae, with a revised taxonomic list of species of Myxobolus known from North American freshwater fishes

1995 ◽  
Vol 52 (S1) ◽  
pp. 7-12 ◽  
Author(s):  
David K. Cone ◽  
Richard L. Raesly
Keyword(s):  
North America ◽  
Connective Tissue ◽  
Freshwater Fishes ◽  
Front View ◽  
Spore Size ◽  
Rhinichthys Cataractae ◽  
Rhinichthys Atratulus ◽  
Large Round ◽  
Blacknose Dace ◽  
Formalin Fixed

Myxobolus rhinichthidis Fantham, Porter and Richardson, 1939 (Myxosporea) is redescribed from longnose dace (Rhinichthys cataractae) in Maryland. Large round plasmodia occurred in the connective tissue of the skin covering the head and opercular regions. Fixed spores are oval in front view and measure 11.5–14.5 μm long, 9.0–10.5 μm wide, and 6.0–7.0 μm thick. The polar capsules are 5.5–7.0 μm long and 3.0–3.5 μm wide. Photomicrographs of formalin-fixed spores document variation in spore size and shape. The report is the first for M. rhinichthidis since the species was described from blacknose dace (Rhinichthys atratulus) in Quebec. An updated list of species of Myxobolus Bütschli, 1882 reported from freshwater fishes in North America is provided. Myxobolus jahnricei Landsberg and Lom, 1991 is considered a junior synonym of Myxobolus filamentus Grinham and Cone, 1990; and Myxobolus lii Desser, 1993 and Myxobolus gibbosus Li and Desser, 1985 are junior synonyms of Myxobolus uvuliferus Cone and Anderson, 1977.

Reproductive Isolation Between Two Sympatric Dace, Rhinichthys atratulus and R. cataractae, in Manitoba

1970 ◽  
Vol 27 (12) ◽  
pp. 2125-2141 ◽  
Author(s):  
Victor G. Bartnik
Keyword(s):  
Great Lakes ◽  
Reproductive Isolation ◽  
Sympatric Species ◽  
Courtship Behaviour ◽  
Rhinichthys Cataractae ◽  
Rhinichthys Atratulus ◽  
Spawning Behaviour ◽  
Blacknose Dace

The Mink and Valley rivers, Manitoba, contain two sympatric species of dace (Cyprinidae: Rhinichthys). These fishes, although interfertile, have never been reported to hybridize in nature.Seasonal isolation is only partially developed, since overlap in time of spawning exists. During spawning, adults of the two species tend to occupy different habitats, the Great Lakes longnose dace Rhinichthys cataractae cataractae being most abundant in water velocities faster than 45 cm/sec and the western blacknose dace R. atratulus meleagris in water velocities less than 45 cm/sec; but some overlap exists. However, the place of spawning of the two species is distinctly different. Nests of longnose dace were found in water velocities exceeding 45 cm/sec with large stones, whereas nests of blacknose dace were found in slower water velocities in gravel. The patterns of spawning behaviour of these two cyprinids reveal marked differences and obvious incompatibilities. Males of both species actively defend territories prior to spawning but show distinct preferences for conspecific females over other females. Observations further indicate that females are receptive only to patterns of courtship behaviour shown by males of their own species.The combination of different places of spawning and patterns of behaviour is considered to be a powerful barrier to hybridization.

scholarly journals Chronic interstitial pneumonia with features of organizing pneumonia in an adult horse

2020 ◽  
Vol 32 (4) ◽  
pp. 621-625
Author(s):  
Miguel F. Carrillo ◽  
Deborah Kemper ◽  
Leslie W. Woods ◽  
Francisco R. Carvallo
Keyword(s):  
Connective Tissue ◽  
Interstitial Pneumonia ◽  
Bacterial Pneumonia ◽  
Organizing Pneumonia ◽  
Respiratory Problems ◽  
Nodular Pattern ◽  
Quarter Horse ◽  
History Of ◽  
Alveolar Septa ◽  
Formalin Fixed

A 22-y-old American Quarter Horse gelding was presented with a history of chronic progressive respiratory problems and a diffuse pulmonary nodular pattern in thoracic radiographs. The horse was euthanized, and 4 formalin-fixed samples of lung were submitted for histopathology. There were multifocal areas of marked thickening of alveolar septa as a result of proliferation of myofibroblasts embedded in fibromyxoid matrix (interpreted as “Masson bodies”), focal areas of fibrosis, and numerous papillary projections of connective tissue into bronchioles. A diagnosis of organizing pneumonia was reached. No etiology was found for this lesion. It is important to consider causes of chronic interstitial pneumonia with fibrosis in horses other than equid herpesvirus 5, such as complicated viral or bacterial pneumonia or chronic toxicoses.

Postglacial dispersal of freshwater fishes into Ontario

1992 ◽  
Vol 70 (11) ◽  
pp. 2247-2259 ◽  
Author(s):  
Nicholas E. Mandrak ◽  
E. J. Crossman
Keyword(s):  
North America ◽  
Freshwater Fishes ◽  
Eastern North America ◽  
Glacial Period ◽  
Before Present ◽  
Last Glacial Period ◽  
Historical Processes ◽  
Dispersal Routes ◽  
Atlantic Coastal ◽  
The Last Glacial

The present-day distributions of 117 native freshwater fishes in Ontario have been shaped by processes active following the Wisconsinan glacial period, 80 000–10 000 years before present. During this glacial period, these species survived in unglaciated réfugia. To understand the processes that resulted in the recolonization of Ontario by fishes following the last glacial period, the refugial areas occupied by each species were determined using a refugial index, and glacial water bodies used as dispersal routes were identified. The refugial origins of the Ontario populations of 91 species were resolved. Seventy-two species resided in the Mississippian refugium, 13 species in the Atlantic Coastal refugium, 4 species in dual Atlantic Coastal – Mississippian refugia, 1 species in a Missourian refugium, and 1 species in Atlantic Coastal, Mississippian, and Missourian refugia. These conclusions differed significantly from those of other studies. Five general patterns were identified from the distributions of 104 species. In addition, there are 13 species that do not fit any of the general patterns. Most species with similar distributions in Ontario shared the same refugia and dispersal routes in eastern North America, therefore it is hypothesized that historical processes were important in shaping the present-day distributions of Ontario freshwater fishes.

Spore morphology and taxonomy of Isoetes in northeastern North America

1983 ◽  
Vol 61 (12) ◽  
pp. 3140-3163 ◽  
Author(s):  
L. Kott ◽  
D. M. Britton
Keyword(s):  
North America ◽  
Spore Morphology ◽  
Key To Species ◽  
Northeastern North America ◽  
Spore Size ◽  
Distribution Maps

Taxonomy of Isoetes L. largely rests on megaspore and microspore wall ornamentation and spore size. These characters have been reevaluated and the range of their variability is described (SEM photographs). Eight species of Isoetes are recognized for northeastern North America: I. macrospora, I. hieroglyphica, I. tuckermanii, I. riparia, I. acadiensis, I. echinospora, I. eatonii, and I. engelmannii. Each species is provided with a revised list of synonyms, description, ecological notes, representative specimens, and distribution maps. A key to species is provided.

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