Date of Award:

1968

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Department name when degree awarded

Zoology

Advisor/Chair:

Merrill H. Gunnell

Abstract

A new species of planaria in the genus Phagocata was found in several springs and spring-fed streams in Logan Canyon, Cache County, Utah. This species was named Phagocata crenophila because it greatly prefers to live in springs and it seems to be adapted behaviorally to this type of habitat. Serial sections and whole mounts were made by standard methods in order to study the anatomical features which are necessary for identification of planarians. The distinguishing features of this species are the following: testes ventral and extending from near the brain to near the posterior end, ejaculatory duct opening ventrally from the penis, penis short and rounded with a prominent finger-like lobe at the tip, two eyes situated far back on the truncated head, and color usually dark gray. Comparisons to similar species are made, and a new key to the species and subspecies of the genus Phagocata is proposed.

Several experiments were performed on cultured lab animals in order to determine their reactions to temperature and to current. Most animals which were kept in a refrigerator at l6°C. survived for a month or more. Several short experiments were performed using an artificial current created in 1000 mL. beakers by an electric magnetic stirrer. These tests indicate a fairly great tolerance of relatively high temperatures (16°C.), but a greater ability of P. crenophila to orient into a current and to resist being swept away by a strong current than Polycelis coronata with which it lives naturally.

The ecology of each spring or stream in which the new species is found is discussed briefly. Observations throughout the year indicate that P. crenophila prefers cold, fast flowing head waters of streams with substrates composed of rocks and moss. P. crenophila may be able to better survive the strong current or the winter dry periods at Ricks Spring than P. coronata, thus resulting in a greater proportion of the former species in this spring. In other springs, populations of P. crenophila appear to be limited, at least partially, by the large populations of P. coronata.

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