Baculites sp smooth and weak flank ribs Mooreville Chalk Alabama

There are approximately 150 isolated aptychi. They are attributed to Baculites sp. (smooth) and Baculites sp. (weak flank ribs) by comparison with the jaws inside the body chambers of these species and the fact that these two species occur in age-equivalent strata elsewhere. In terms of measurable specimens, the collection contains 8 pairs of valves found in close association, 19 left valves, and 11 right valves. The valves range from 15.2 mm to 38.6 mm in length and 6.4 mm to 17.2 mm in width,...

Whorl Height Expansion and Whorl Width Expansion

Both expansion rates of whorl height and whorl width display drastic ontogenetic changes (Fig. 3.6C-F). These changes can be grouped into (1) major ontogenetic trends, i.e., transformations that occur over more than two whorls, and (2) spontaneous changes, i.e., changes that occur only sporadically and are not part of continuous trends. Different modes of calculation of the WHER and WWER display the two modes of ontogenetic transformation Squared expansion per half whorl (WHERt and WWERt),...

Life Cycle of Manticoceras

Because of their large maximal conch size, the adult body chambers of Manticoceras could have housed an enormous number of eggs. Presuming that ammonoids hatched during or after the formation of the primary constriction (at an ammonitella size of less than 2 mm) and that Recent cephalopod eggs grow during the development of the embryo (compare the coleoid Illex, Sakai et al., 1998), it appears reasonable to infer an initial egg size of manticoceratids of 1-2 mm, which increased to a size of 2-3...

Cravenoceras fayettevillae Gordon

The siphuncular membranes in Cravenoceras fayettevillae also appear as a series of simple, evenly spaced, adorally concave sheets between the siphuncle and ventral Fig. 9.8 Cravenoceras fayettevillae Gordon, 1965, AMNH 51233, lower Fayetteville Shale, Fayetteville, Arkansas. Dorsoventral views of the siphuncle and siphuncular membranes. A. Overview of several whorls. B. Close-up view of a portion of the siphuncle (s), showing siphuncular membranes. C. Close-up view of the central portion ofB,...

Facies and Taphonomy

The ammonoid-bearing Famennian sequences of the Uralian-Kazakhstanian Region are highly condensed in western Kazakhstan, but become thicker to the north (Bashkortostan) and are particularly thick in central Kazakhstan. Zones in the Rhenish Massif Becker & House, 2000 Becker et al., 2002 Genozones (Becker, 1993 Becker & House (2000) Zones of the Rhenish Massif (Korn, 1981, 1986) Zones of the Rhenish Massif (Korn, 1999 Kom& Ziegler, 2002) Fig. 15.2 Correlation of the Famennian ammonoid...

DNA Sequence Data

In most cases, molecular data provide informative phylogenetic indications for determining evolutionary relationships between sibling species or at least morphologically nearly identical species. A famous example is the study of teleost fish species by Sturmbauer and Meyer (1992). Numerous, nearly morphological identical cichlid species recognized in Lake Tanganyika are genetically divergent. The genetic divergence within these species displays twice as much as the genetic divergence within the...

Distribution of Ammonoid Faunas in the Uralian Ocean

The first ammonoids in the Uralian Ocean appeared in the Emsian. In the Eifelian to Frasnian, the paleogeographic settings were different from those in the Famennian (Fig. 15.7). The ocean was more open toward the east with ammonoid Fig. 15.7 Paleotectonic reconstruction for the Early-Middle Devonian modified from Puchkov (2000) 1- continents, microcontinents, island arcs 2 - other areas of continental crust 3 - areas with oceanic crust 4 - Uralian Ocean 5 - rifts, 6 - continental rifts 7 -...

Description of Ammonite Touch Marks

Careful examination of the ammonite touch marks reveals the species that probably produced them (Figs. 18.4-21, arranged in taxonomic order). The main evidence for this determination is the impression of the ornamental features (ribs, tubercles, and keels), which form a distinctive pattern. We compared this pattern to specimens in our collections, bearing in mind that the pattern of ornamentation commonly changes during ontogeny. We examined those ammonites known to occur in the same strata as...

Pseudobaculites natosini Lewis Shale Wyoming

BHMNH 5501 is 50.1 mm long but is incomplete (Fig. 13.24A, B Table 13.1). Each wing is approximately 25.8 mm wide. The specimen is folded in half along the symphysis. A flange is present on the middle one-third of the jaw. The posterior margin is broken but the lateral margin is intact and broadly curved. The apex is more strongly convex than the rest of the wing. The jaw is preserved as a fine-grained, tan layer covered by a dark brown to black, coarsely crystalline layer 160 im thick. This...

Paleobiogeography and Paleoecology of Placenticeras kaffrarium

The genus Placenticeras has a wide geographic distribution, but species in any particular time are endemic and show clustered distribution patterns (Bardhan et al., 2002). They appear to have been constrained by latitudinal factors and, at times, were highly provincialized. Throughout their geological distribution, placenticeratids flourished best in the subtropical region on either side of the equator. For example, the earliest groups during the Albian-Cenomanian were mostly clustered in...

Baculites sp weak flank ribs Cody Shale Wyoming

A lower jaw (BHMNH 5331) occurs inside the adoral end of a weathered fragment of a body chamber of Baculites sp. (weak flank ribs) (Fig. 13.15, Table 13.1). The body chamber fragment is 111.0 mm long with a maximum whorl height of 33.8 mm. The long axis of the jaw is oriented at an angle of 70 with the long axis of the body chamber. The anterior end of the jaw points slightly backward against the ventral ( ) side of the shell. The jaw is folded along the symphysis so that the two wings are...

Late Carboniferous Coleoid Cephalopod from the Mazon Creek Lagerstatte USA with a Radula Arm Hooks Mantle Tissues and

Mapes,2 and Harry Mutvei3 'Paleontological Institute of the Russian Academy of Sciences, St. Profsoyuznaya, 123, Moscow 117997, Russia, ldoguzhaeva rambler.ru 2Department of Geological Sciences, Ohio University, Athens, OH 45701, USA, mapes ohio.edu 3Department of Palaeozoology, Swedish Museum of Natural History S-10405 Stockholm, Sweden, harry.mutvei nrm.se 2 Studied Material, State of Preservation, and 3 Comparative 3.2 Cephalic 3.2.2 Arm 3.3 Fossilized...

References

Thorpe, and P. G. Rodhouse. 1997. Restricted gene flow and evolutionary divergence between geographically separated populations of the Antarctic octopus Pareledone turqueti. Marine Biology 129 97-102. Allcock, A. L., and S. B. Piertney. 2002. Evolutionary relationships of Southern Ocean Octopodidae Cephalopoda Octopoda and a new diagnosis of Pareledone. Marine Biology 140 129-135. Anderson, F. E. 2000. Phylogeny and historical biogeography of the loliginid...

Systematic Paleontology

The following features of the morphology and preservation in the specimens under discussion were analyzed to elucidate their systematic assignment 1 division of the shell into a proostracum-like structure, body chamber, phragmocone, and rostrum 2 presence of fossilized soft-tissues covering the shell 3 presence of the arm hooks, 4 presence of ink, and 5 a unique radula structure. Fig. 6.11A, B Austrotrachyceras sp., NHMW2005z 0006 0001, Upper Triassic, Lower Carnian, Lower Austria, locality...

Function of the Aptychus Type

The aptychus type jaw has generally been interpreted as an adaptation for feeding on small prey microphagy Morton and Nixon, 1987 Lehmann and Kulicki, 1990 Seilacher, l993 Engeser and Keupp, 2002 . Several morphological features of the jaw have been cited in support of this interpretation 1 the presence of a blunt anterior margin with the two wing tips diverging at the apex, 2 the general absence of a thickened calcareous deposit at the apical end, 3 the presence of a groove, rather than a...

Relocation Experiment

Tag retention, determined as the time postrelease before the tag stopped moving for all subsequent relocations, was 17-51 days in 1996, but less than 24 h in 2003 due to different attachment methods. Thus, results in 2003 reflect very short-term movements, and do not necessarily indicate final choice of habitat. Immediately on release, octopuses either readily reoccupied their previous dens 1996, released where captured , sought nearby shelter under kelp if it was available 2003, shallow...

Baculites sp smooth Pierre Shale South Dakota

The body chambers containing lower jaws are fragmentary and range from 43.2 mm to 120.9 mm in length Figs. 13.4-14, Table 13.1 . All of the body chambers are steinkerns but several retain pieces of the aragonitic outer shell composite internal molds . The body chambers consist of four stout and eight slender individuals, presumably representing mature macroconchs and microconchs, respectively. In specimens that preserve the ultimate septum or in which the shell expands enough to detect the...

Migrational Routes and Paleolatitudinal Disposition of Kutch

The above mentioned Late Tithonian assemblage of Kutch thus suggests a complex pattern of migrational history of ammonite taxa from different provinces and at the same time dispersal of endemic forms species level to other areas. The presence of genera previously known in different provinces indicates a grand migrational event during the global sea level rise. This large scale transgression helped establish seaway connections among various isolated or semi-isolated basins. Many of the immigrant...

Upper Tithonian Assemblages of Different Faunal Provinces

The paleobiogeographic history of Mesozoic ammonites is marked by the repeated alternation of high degrees of provincialism and cosmopolitanism. The peak of ammonite provincialism occurred during the Late Jurassic and Early Cretaceous Gordon, 1976 . Different names were given for the Upper Jurassic stages in different regions because of this high endemism, i.e., Tithonian in the Tethyan and Indo- v-sripta I. beyschlagi Ammonite bands Fig. 17.2 Stratigraphic section showing the position of the...

Bdesheim

Of the cross sections of manticoceratids from B desheim Eifel that were published by Clausen 1969 , four characteristic individuals are highlighted in Fig. 3.11. The minute pyritized material comes from dark shales, and the question arose whether these specimens, which are less than 20 mm in diameter, portray similar ontogenetic trajectories to the normal-sized material from other localities. The manticoceratids from B desheim have conchs with ontogenetically accelerated coiling rate WER Fig....