Pseudacris Crucifer Research Articles

A Mutant Red-Phase Wood Salamander (Plethodon cinereus) from New Hampshire

This is a report on several series of amphibians and reptiles, received from New Hampshire during the spring of 1945. The most interesting of these specimens were eight wood salamanders from Andover, Merrimack County: seven of the common red-backed phase described by Bishop (1943, Handbook of Salamanders, p. 234), none of the lead-backed or dark phase, and one of a new all red phase not mentioned by Bishop. The red mutant was typical of Plethodon cinereus in every way, except for lack of dark pigment on the sides and below. It was uniform light red from the lower flanks upward and light below. The collector of this specimen was Miss Katherine Gulick, who also sent from the Andover area: Desmognathus fuscus fuscus, dusky salamander; Eurycea bislineata bislineata, two-lined salamander; Triturus viridescens viridescens, eastern newt; Hyla crucifer, spring peeper; Rana palustris, pickerel frog; and Chrysemys picta picta, eastern painted terrapin. Additional New Hampshire records from 1945 collecting: young Hyla crucifer taken at Raymond, Rockingham County, by Robert A. Hellman; water stage Triturus viridescens viridescens found at Meredith, Belknap County, by Peter Lunt and the red eft land stage at Webster Lake in Merrimack County by Irene Wilson; and the milk snake Lampropeltis triangulum triangulum secured at Andover, Merrimack County, by Winslow Trueblood.

QUANTITATIVE ASSAY OF THE MELANOPHORE DISPERSING HORMONE DURING THE DEVELOPMENT OF THE CHICKEN PITUITARY1

TWO OBSERVATIONS SUGGESTED the rather early appearance of the melanophore dispersing hormone during ontogeny. It was first called to our attention by the results of hypophysectomy of the Spring peeper (Pseudacris triseriata) embryos. In these forms the melanophores were easily distinguished and revealed complete concentration of pigment at a time when the control animals were hatching from their jelly envelopes. Secondly preliminary experiments showed that head extracts of recently hatched Rana pipiens larvae yielded considerable amounts of melanophoredispersing hormone when injected into hypophysectomised Anolis lizards, while the control body extracts gave a negative response. Histological examination of control pituitaries revealed no cytoplasmic differentiation. These observations suggested, not only the presence of the melanophore'dispersing hormone in the undifferentiated gland, but also revealed its functional rOle during very early development.

The Breeding Habits of Pseudacris brachyphona (Cope) with a Description of the Eggs and Tadpole

T HE mountain chorus frog, Pseudacris brachyphona, was first described by Cope in 1889 as a variety of Chorophilus feriarum. No further attention was paid to it until 1932 when Walker (1932: 379) removed it from its obscure position and established it as a valid species. Netting (1933: 4) records it from five counties in West Virginia; Walker (1932: 381) gives the measurements of three West Virginia specimens from the Carnegie Museum; Wright and Wright (1933: 84) record it from the extreme southern part of West Virginia. Despite the fact that Pseudacris brachyphona is fairly common throughout the central and southern part of West Virginia, where it has been collected between altitudes of 1200 feet and 3500 feet, little seems to be known about its life history and breeding habits. Walker (1932: 383) gives a brief description of the eggs and of the situations in which they are laid. Wright and Wright (1933: 85) state that the tadpole has not been described, and that there are no data on transformation. During the spring months of 1936 and 1937 the author had an opportunity to observe the breeding habits of this frog as well as to collect the eggs and tadpoles at various stages. Most of the observations were made in the vicinity of Elkins, Randolph County, and in Tucker County, lying to the east of Randolph; other specimens were collected and notes were taken in Barbour, Upshur, Braxton and Pocahontas counties, all in West Virginia. The preserved material on which the paper is based is in the author's private collection. In central West Virginia Pseudacris brachyphona begins calling about the first of April. It is the third frog voice to be heard in the spring in Randolph County. Hyla crucifer and Rana sylvatica have been calling for two to four weeks before it emerges. The males appear two to four days before the females and congregate in temporary pools and drainage ditches from which they call lustily. They line the edges of the pools, stationing themselves either in or out of the water. Most of the males collected were in the water with their backs to the edge of the pool. Those taken from the bank were facing the pool and a short distance from it. They collected on mats of algae or other vegetation or floated with legs outstretched. They showed a decided preference for shallow and slow-moving or quiet bodies of water and no specimens were seen near permanent bodies of water. On one occasion several individuals were found calling from water-filled furrows of a freshly ploughed field. They make no effort to conceal themselves in the stubble or rubbish around the pools as does Hyla crucifer. Frequently there were fifteen or twenty males around the edge of a pool five feet in diameter. Along ditches there were often three or four males every two feet. The males were more plentiful than the females; the ratio of sexes seen and collected was about six to one.

Experimental Formation of Accessory Organs in Mid Body Lateral-Line of Amphibians.

The ability of primary lateral-line organs in amphibians to form accessory ones by budding,, the time at which these bud organs are developed, and the pattern of organ groups gave a method for measuring the effects of the present experiments in amphibians. When the placodes of the mid-body lateral-line primordia of young and older tail-bud stages of Amblystoma punctatum (Harrison stages 23-24 and 28-29) are exchanged, the age difference between graft and host organ-forming tissue can be clearly followed through the young larval stages by observing the time at which accessory organs are laid down by the budding of primary ones. In A. punctatum the dorsal and ventral poles of primary organs give rise to accessory organs forming lineal groups of 2 or 3. In A. tigrinum by a similar process groups of from 4 to even 8 are formed, usually in irregular clusters, as in Rana palustris and Hyla crucifer. There is multiple budding of both primary and accessory organs. When the mid-body lateral-line primordia are exchanged in the tail-bud stages of punctatum and tigrinum the formation and grouping of organs from the graft follow only that of the donor species. When the lateral-line primordium of A. punctatum is placed on the body of A. tigrinum in the future pathway of the primordium of the host, the one of the graft will migrate and form organs only when the primordium of the host touches and fuses with similar material of the graft. The phenomenon is similar to that previously reported. At the appropriate times accessory organs are developed, which in size and group formation are identical with those of the donor species. The organs are innervated by the host lateral-line nerve and never were observed to degenerate up to late larval life.

Developmental Changes in Primary Lateral-Line Organs Studied in Living Larvae of Anurans and Urodeles

In amphibian embryos the migrating lateral-line primordia lay down a series of primary organs which can be observed in the living and vital-stained condition.1, 2 Since the mid body line extends down the tail in rather transparent tissue such organs are favorable for study in the living specimen when observed under high magnification in micro-aquaria. These data concerning the developmental changes in primary tail organs of normal larvae provide a basis for further observations consequent to the cutting of the lateral-line nerve. In Amblystoma punctatum larvae the large melanophores often obscure the view of many lateral-line organs and their nerves. This condition was easily avoided by feeding specimens an exclusive diet of enchytraea which, for some unknown reason, contracts the dark pigment cells. The animals become pale yellow in color. In Hyla crucifer tadpoles pigment presents no serious difficulties. In contrast to the normal pigmented larvae of Rana palustris it was found that hypophysectomized specimens gave as clear a picture as Hyla. In Amblystoma punctatum the tail organs begin abruptly at a level above the anus. In many larvae studied at the feeding stage (Harrison stage 46, 15-16 mm.) such a line on the tail is about 18 in number, extremes being 13 to 20. As in other lines the number on the right side is usually not equal to that on the left. From primary organs accessory ones are formed by budding from supporting cells.1, 2 Shortly after the feeding stage begins the terminal organ may give off a bud posteriorly and thus form a chain of 1 to 3 new organs. However, normal isolated animals often do not show an immediate response by budding of the terminal organ until later.