Antler Formation Research Articles

Effects of an antiandrogen treatment on the antler cycle of male fallow deer (Dama dama L.).

Weekly application of the antiandrogen cyproteron acetate (CA) to 3 adult (group 1, treatment starting 3 weeks prior to the rut) and 4 subadult (group 2, treatment starting after the rut) fallow bucks led to premature antler casting after about 9 weeks (group 1) or 16 to 17 days (group 2). Variation in time span between onset of CA administration and induced casting (in late November/early December) is attributed to age- and season-dependent differences in androgen levels before and during the treatment period. Casting surfaces of the antlers were flat. In all bucks, casting was followed by a complete though shortened antler cycle, occurring under short day conditions. In February/March velvet was shed from the antlers, indicating a rise in plasma androgen levels at that time. At time of fraying, antlers exhibited signs of immaturity and were shorter than normal. In the most pronounced case of immaturity, the antlers consisted mainly of cancellous woven bone, revealing that bone remodeling and antler mineralization had not occurred to a larger extent. These observations prove that onset of fraying behaviour does not depend on prior maturation of antler bone or necrosis of velvet. Occurrence of the additional antler cycle in late autumn and winter had no negative effect on subsequent antler formation starting in the following spring.

Secondary sex characteristics and related physiological values in male fallow deer (Dama dama L.) and their relationships to changes in the annual cycle of daylengths: frequency alterations to 4- and 3-month photoperiodic cycles, and subsequent re-synchronisation under natural conditions.

Five adult male fallow deer were maintained in a barn with artificial light control. In a previous experiment, three 6-month photoperiodic cycles entrained morphogenetic and associated physiological values that revealed typical relationships to the antler cycle. Presented here, the light cycle was accelerated to three 4- and one 3-month photoperiods in the same group. Each artificial photoperiod generally resulted not only in an almost complete antler cycle but also in an entire cycle of seasonal fluctuations in neck girth. Increases in plasma levels of alkaline phosphatase (AP), total-, LDL- and HDL-cholesterol, were generally entrained and the maxima revealed positive correlations with antler formation, but the relationships slightly diverged. In neck girth and creatinine, positive correlations to the hard antler period as well as to each other prevailed but diverged. In the 3-month photoperiodic cycle, these relationships were out of synchrony. In the second 4-month cycle, two bucks "missed" shedding and subsequent casting, but commenced antler growth in the following cycle with an in-time shedding. The possibility of desynchronisation of physiological conditions and the question of an endogenous circannual mechanism interacting with daylight are discussed. At the end of the 3-month cycle, experimental indoor and natural outdoor casting was coincident so the group was transferred to outside conditions for re-synchronisation. After spending altogether 36 months in frequency altered photoperiods, the represented values were neither synchronized nor revealed their typical relationships to the antler cycle, except of AP and neck volume. In the second cycle of re-synchronisation, all parameters, except of creatinine, appeared to be resynchronized.

An azhdarchid pterosaur humerus from the Lower Cretaceous Glen Rose Formation of Texas

Pterosaurs are rare components of Texas Cretaceous faunas. The best known is Quetzalcoatlus northropi, from the Javelina Formation (Maastrichtian) of Big Bend National Park, with a wingspan of some 11-12 m (Lawson, 1975; Langston, 1986; Busbey and Lehmann, 1989). Texas pterosaur specimens of less spectacular proportions include a pteranodontid partial humerus (USNM 13804) from the Eagle Ford Formation (late Cenomanian-late Turonian) of Austin (Gilmore, 1935; Bennett, 1989) and a first wing phalanx of a pterodactyloid from the Buda Formation (Cenomanian) of Hays County (Langston, 1974; Lawson, 1975). Pterosaur bones were also recorded at localities near Forestburg, Montague County (Zangerl and Denison, 1950), in the Antlers Formation (Winkler et al., 1990), although these specimens are undiagnostic hollow bone fragments.

Early Cretaceous (Comanchean) vertebrates of central Texas

ABSTRACT Vertebrates from the Comanche Series (Lower Cretaceous) in central Texas occur in the superposed Twin Mountains, Glen Rose, and Paluxy formations. Stratigraphie position and relationship to marine units are more clearly defined for the central Texas localities than for the classic mammal-producing sites in the Antlers Formation of north-central Texas. The diverse terrestrial to marine faunas include new records for the ray Rhinobatos, a ptychodont (cf. Hylaeobatis ornata), and the salmoniform Enchodus. Anurans, salamanders, lacertilians, and mammals representing early forms relevant to the emergence of extant higher taxa are present but fragmentary. Crocodilians are represented by at least three taxa and theropods by more than three. Eight species of mammals have been named from the Comanche Series, with perhaps as many as four other unnamed species represented. Paleoenvironments appear to control the distribution of taxa: dinosaurs are found in coastal settings and are abundant in some terrestri...

Secondary sex characteristics and connected physiological values in male fallow deer (Dama dama L.) and their relationship to changes of the annual photoperiod: Doubling the frequency

AbstractFive male fallow deer, who were at the time of casting their first antlers, were maintained in a barn with artificial light control. The daylength sequence applied simulated an amplitude which was normal for 52° latitude, but each cycle lasted only 6 months. This photoperiod produced a doubling in frequency of morphogenetic and connected physiological values so that three complete antler cycles were reached within 19 months. Increase in levels of alkaline phosphatase and in concentrations of total‐cholesterol (TC) and low‐ and high density lipoprotein cholesterol (LDL‐C and HDL‐C) followed the frequency of light alterations and correlated well with antler formation. On the other hand, an increase in neck circumference as well as increase of creatinine levels correlated well with the hard antler period of fertility as well.

Late Paleozoic conodonts from ribbon chert delineate imbricate thrusts within the Antler Formation of the Slide Mountain terrane, central British Columbia

Late Devonian?–early Carboniferous to Permian conodonts from the Antler Formation of Slide Mountain Group near Barkerville, British Columbia, were extracted from 23 of 28 chert samples collected from a nearly continuous section on Sliding Mountain. The conodonts delineate three, possibly four, thrust sheets within the section. From bottom to top the ages recorded in the sheets consist of (I) Early Permian, (II) Pennsylvanian to Early Permian, (III) Early Mississippian to Early Permian, and (IV) Late Devonian? or Early Mississippian. In sheet III, 100 m.y. of chert and basalt stratigraphy, the entire known age span of the Antler Formation, is recorded in less than 300 m. Prior to thrust imbrication the Antler Formation must have been very thin and possibly covered a large area. Within individual thrust sheets, the stratigraphic features and their continuity are preserved.

Seasonal variations of serum 1,25-dihydroxyvitamin D3 and alkaline phosphatase in relation to the antler formation in the fallow deer (Dama dama L.).

Serum 1,25-dihydroxyvitamin D3 and serum alkaline phosphatase increased several fold during the antler formation period in July. Both maxima were observed in the second half of the antler formation period, where the mineralization of the antler takes place. In contrast serum levels of calcium and 25-hydroxyvitamin D3 showed no alternation or seasonal variation.

Perspective

Robert Burns’ poem ‘My Heart's in the Highlands’ confirms that deer have been an important element of the Scottish Highlands for many years. But, what is distinctive about them? They can be separated from other vertebrates by an array of characteristic features including the absence of a gall-bladder, the doubling of the lachrymal orifice and the development of deciduous bony outgrowths of the frontal base of the skull—the antlers. In his paper, Lincoln discusses the shedding and regeneration of antlers with associated spring minimal, and autumn maximal, concentrations of testerone. He also describes how, in most young stags, antler formation will proceed unaided with successive annual developments being triggered by a healing response to the wound formed when the old antlers are cast. In other congenitally antler-less stags (hummels), it seems that antler formation can be induced in perpetuity by wounding antler pedicels, each of a pair needing to be damaged separately.

Marginal Marine Evaporites, Lower Cretaceous of Arkansas: ABSTRACT

The mixed evaporite/carbonate/terrigenous clastic sediments of the DeQueen formation, in southwestern Arkansas, were deposited at the End_Page 1467------------------------------ landward margin of a broad shallow lagoon formed behind the Glen Rose reef. About 60% of the sedimentary volume consists of mudstone, silt, and sand, with brackish-water to hypersaline ostracod faunas believed to result from influx of flood waters from the Ouachita highlands a few miles to the north. The lower part of the formation contains discontinuous beds of gypsum, ranging in thickness from a few centimeters to composite beds > 3 m (10 ft), and displaying mosaic structure with vertically oriented, elongate nodules. These beds, which are lenticular, are interpreted to result from subaqueous precipitation of vertical selenite crystals (subsequently recrystallized) in discrete ponds and pools on microtidal-range mud flats. Intrastratal growth of gypsum nodules and displacive hali e occurred at the margins of the pools. The upper part of the formation contains no gypsum beds, but halite pseudomorphs at the base of and within some of the thin limestones suggest the presence of supratidal brine pools. Several minor unconformities exist, of which one has a regional extent and is underlain by red-brown mudstones. Algal-mat lamination, lenticular gypsum pseudomorphs (an intrastratal growth form), and syneresis cracks occur in the limestones, and a supratidal environment is envisaged for a significant proportion of the time of deposition. The limestones generally have a restricted fauna of ostracods, bivalves, cerithid gastropods, serpulid worms, and miliolid Foraminifera, and range in texture from lime mudstones to grainstones. The most abundant grain types are pellets, superficial ooliths, and terrigenous quartz. A paucity of dolomite is a striking feature. Some of the thinner bedded units are rippled, and some ripples were truncated during periods of emergence. The limestones are believed to represent periods of shallow water, slightly hypersaline to slightly hyposaline conditions of variable energy. The regressive trend displayed by these two divisions continued with deposition of the overlying formation. The uppermost 3 m (10 ft) of the DeQueen consists of mudstone with a thin marl at the top. A conformable contac exists with the overlying Antlers formation, which has basal mudstones becoming more silt- and sand-rich upwards and finally giving way to the typical Antlers (Paluxy) sands. End_of_Article - Last_Page 1468------------

A re-examination of the type area of the Devono-Mississippian Cariboo Orogeny, central British Columbia

Three tectonostratigraphic successions are established from remapping of the area near Barkerville and Cariboo River. The first, of Late Proterozoic to Cambrian sediments, was deposited on the shallow to moderately deep platformal shelf west of and derived from the exposed North American craton. The second is an unconformably overlying Ordovician to Permian sequence of sedimentary and volcanic rocks representing a basinal environment with periodic highs. These packages of sediments were deposited on the North American craton and its western transitional extensions. The third succession, composed of oceanic chert and basalt of the Permo-Pennsylvanian Antler Formation, was thrust eastward over the other two during the early Mesozoic. The three successions were folded, faulted, and metamorphosed during the mid-Mesozoic Columbian Orogeny. The Devono-Mississippian Cariboo Orogeny, which was thought to have affected all of the first sequence and part of the second, could not be documented in its type locality. The geology of the Barkerville – Cariboo River area has many similarities with that of Selwyn Basin and Cassiar platform of northern British Columbia and Yukon.

Nonmarine Depositional Environments and Uranium Exploration in Lower Cretaceous Antlers Formation, North Texas: ABSTRACT

Detailed geologic and geochemical investigations of the Sherman quadrangle for the National Uranium Resource Evaluation (NURE) program have included fluvial deposits of the Antlers Formation which are exceptionally well exposed in cliffs along the shores of Lake Texoma, Grayson County, Texas. These deposits accord with the classical mixed-load, meandering-river model, with erosively based pebbly sandstones grading upward into silty sandstones and carbonaceous mudstones with sporadic lignitic material. Lateral-accretion bedding of presumed point-bar origin is inclined at angles up to 10°. Thickness of these lateral accretion units permits estimates of channel depth of as much as 12 m. Distinct channel forms, some of which are clay filled, are up to 100 m wide, but sub tantially lower estimates of channel width are obtained from dimensions of the point-bar stratification. Flanking and overlying the in-channel sands are inclined levee deposits, chutes and chute bars, proximal to distal crevasse splays, and organic-rich backswamp clays. Preliminary radiometric analyses show low to very low readings for the major channel sands, with a general trend of increasing radioactivity with decreasing grain size, decreasing bed thickness, and increasing organic content. Thus the most distal, or sediment-starved, overbank facies composed of dark laminated clays and lignites show the highest values. These analyses indicate substantial local epigenetic enrichment, but the deposits encountered to date are too small to be considered a potential resource. End_of_Article - Last_Page 831------------

Histological and histochemical periodicity of cervine Leydig cells in relation to antler growth

Seasonal variation in the testicular interstitial cells and seminal vesicles of 52 Colorado mule deer ( Odocoileus hemionus), aged 1.5–7.0 years, was related to phases of the antler cycle to determine whether gonadal activity was altered at the time antler growth was initiated. Concomitant with the onset of antler growth (April), resurgence of testicular activity was indicated by restoration of spermatogenesis and increased nuclear volume and straining intensity of succinic dehydrogenase, 3β-hydroxysteroid dehydrogenase, glucose-6-phosphate dehydrogenase, and fluoride-sensitive esterase in Leydig cells. Changes in enzyme localizations and enhancement of glucose-6-phosphate dehydrogenase indicated stimulation of seminal vesicle glandular epithelium 3–4 weeks after renewed Leydig cell activity. Maximal Leydig cell activity was attained in late September subsequent to velvet shedding. Regression began during the rutting season (November) and proceeded to a baseline of minimal activity (January) that was extant during antler shedding and retained until renewed antler growth. The temporal relatioship between antler growth and gonadal stimulation suggests that gonadotropin secretion is augmented commensurate with antler formation.

Biochemical Investigations of Deer Antler Growth

The localized content of lactic, malic, and glucose-6-phosphate dehydrogenases, phosphoglucoisomerase, alkaline phosphatase, and total phosphate at five selected stages of deer antler formation has been investigated by means of quantitative microchemical methods. Generally, the antler tine has a higher over-all level of enzyme activity than do the epiphyseal plates previously studied. Alkaline phosphatase in the preosseous zones of the tine rises to extremely high levels, much above anything reported in the epiphyseal plate. However, no increase in phosphate content was observed to be associated with the increase in alkaline phosphatase. The source of the seasonal elevation of circulating alkaline phosphatase occurring in male deer is shown in this paper, as well as in the previous paper of the series, to be the preosseous areas of the proliferating antler tine.

Biochemical Investigations of Deer Antler Growth

A colony of thirteen male and female deer have been studied for seasonal fluctuation of blood calcium phosphorus, albumin, globulin, and alkaline phosphatase. The female animals had stable levels of these parameters of body chemistry throughout all periods of the years. The male animals, beginning in May, undergo rapid antler growth, producing a structure equivalent to one-sixth the total skeletal bulk in a three-to-four-month period and have stable levels of calcium, phosphorus, albumin and globulin. This group demonstrated marked rise in serum alkaline phosphatase activity directly coordinated with the rate of antler growth. Amputation of the antler formation led to a sharp decline of circulating alkaline phosphatase, indicating this structure is the source of the enzyme.

Experimental Investigations of Morphogenesis in the Growing Antler

ABSTRACT Investigations of the morphogenesis of antler growth have been undertaken in the sika deer (Cervus nippon). Operations were performed on the left antlers, while the intact right antlers served as controls. Amputation of the terminal centimetre of growing antlers seriously impedes further development except for the production of an abortive outgrowth from the stump. By contrast, transverse amputation through the middle of the pedicle is followed by normal antler formation. Removal of the entire pedicle permits antler development to occur, although at a retarded rate. Therefore, antlerforming potentiality resides in the growing tips of the elongating antler as well as in the tissues of the entire pedicle. The extent of morphogenetic regulation for defects surgically inflicted on the antler bud or pedicle depends on the age of the antler and the location of the injury. Excision of the posterior halves of 1-inch antler buds results in corresponding deficiencies in the antlers produced. The same injury to an extremely rudimentary bud, however, is followed by considerable regulation, and removal of the posterior half of the pedicle prior to shedding of the old antler has no effect on the normal development of the resulting antler. Ablation of anterior or median halves of pedicles likewise causes no morphogenetic abnormality, but if the lateral half of the pedicle is removed no antler develops. The importance of the lateral half of the antler-forming structure is further illustrated by the fact that a complete and normal antler can grow from just the lateral half of a pedicle or of a 1-inch antler bud. The morphogenetic field of the antler can give rise to double antlers if bisected longitudinally; transverse subdivision, however, does not alter subsequent normal production of a single antler. It is proposed that a relationship between the initial mass of antler-forming material and the degree of morphogenetic expression may possibly exist.