Tertiary and Recent marine gastropods include in their ranks a complement of mechanically sturdy forms unknown in earlier epochs. Open coiling, planispiral coiling, and umbilici detract from shell sturdiness, and were commoner among Paleozoic and Early Meso- zoic gastropods than among younger forms. Strong external sculpture, narrow elongate aper- tures, and apertural dentition promote resistance to crushing predation and are primarily as- sociated with post-Jurassic mesogastropods, neogastropods, and neritaceans. The ability to remodel the interior of the shell, developed primarily in gastropods with a non-nacreous shell structure, has contributed greatly to the acquisition of these antipredatory features. The substantial increase of snail-shell sturdiness beginning in the Early Cretaceous has accompanied, and was perhaps in response to, the evolution of powerful, relatively small, shell-destroying predators such as teleosts, stomatopods, and decapod crustaceans. A simul- taneous intensification of grazing, also involving skeletal destruction, brought with it other fundamental changes in benthic community structure in the Late Mesozoic, including a trend toward infaunalization and the disappearance or environmental restriction of sessile animals which cannot reattach once they are dislodged. The rise and diversification of angiosperms and the animals dependent on them for food coincides with these and other Mesozoic events in the marine benthos and plankton. The new predators and prey which evolved in conjunction with the Mesozoic reorganiza- tion persisted through episodes of extinction and biological crisis. Possibly, continental breakup and the wide extent of climatic belts during the Late Mesozoic contributed to the conditions favorable to the evolution of skeleton-destroying consumers. This tendency may have been exaggerated by an increase in shelled food supply resulting from the occupation of new adaptive zones by infaunal bivalves and by shell-inhabiting hermit crabs. Marine communities have not remained in equilibrium over their entire geological history. Biotic revolutions made certain modes of life obsolete and resulted in other adaptive zones becoming newly occupied.

https://www.jstor.org/stable/pdfplus/2400374.pdf

The Mesozoic marine revolution: evidence from snails, predators and grazers

Late Jurassic–Cenozoic reconstructions of the Indonesian region and the Indian Ocean

[1] Lithology describes the geochemical, mineralogical, and physical properties of rocks. It plays a key role in many processes at the Earth surface, especially the fluxes of matter to soils, ecosystems, rivers, and oceans. Understanding these processes at the global scale requires a high resolution description of lithology. A new high resolution global lithological map (GLiM) was assembled from existing regional geological maps translated into lithological information with the help of regional literature. The GLiM represents the rock types of the Earth surface with 1,235,400 polygons. The lithological classification consists of three levels. The first level contains 16 lithological classes comparable to previously applied definitions in global lithological maps. The additional two levels contain 12 and 14 subclasses, respectively, which describe more specific rock attributes. According to the GLiM, the Earth is covered by 64% sediments (a third of which are carbonates), 13% metamorphics, 7% plutonics, and 6% volcanics, and 10% are covered by water or ice. The high resolution of the GLiM allows observation of regional lithological distributions which often vary from the global average. The GLiM enables regional analysis of Earth surface processes at global scales. A gridded version of the GLiM is available at the PANGEA Database (http://dx.doi.org/10.1594/PANGAEA.788537).

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004370

The new global lithological map database GLiM: A representation of rock properties at the Earth surface

Summary
Resemblances between cephalopods and fish

1. Modern cephalopods (coleoids < 1000 species) resemble modern fish (30,000 species) more closely than any of their ancestors did. They have not been replaced by the more diversified group in geological time.

2. The main body of the article (pp. 245–283) reviews these resemblances. They are to be found at all levels of analysis.

3. Basic physiological mechanisms of molluscs (pp. 262–5) have been incorporated into systems with performances comparable to those of vertebrate systems. For instance the cephalopod locomotory system (pp. 249–56) and hydrostatic control system (pp. 256–60), structurally very different from their fish counterparts, have similar adaptive radiation.

4. Behaviour (p. 278) and growth of the brain (p. 265) are characteristically vertebrate-like.

5. Cephalopods and fish are considered as occupying the same broad adaptive zone though modal differences (pp. 283–5)-in reproductive habits, growth rate and light-dependent behaviour where extraocular photoreceptors appear to be important - mean that they occupy different areas within that zone.

(ii) Evolution of convergence

6. Evidence is presented (pp. 287–293) for considering the convergence as due not merely to similar physical demands of the marine environment, but to dynamic interactions between cephalopods and vertebrates from the late Palaeozoic onwards.

7. The convergence was set on its way when the two groups, independently of each other, acquired locomotory methods that allowed them to increase in size.

8. It is argued that reduction and eventually complete loss of the chambered shell (in all but sepiids) was an evolutionary response to the needs of increased mobility and to the need to go deeper as vertebrate predators pushed out into oceanic waters.

9. The ammonites (pp. 291–2) present a partial model of the course that coleoid ancestors may have taken.

10. Coleoids subsequently reinvaded surface and coastal waters, competing successfully in a teleost habitat. Their most striking adaptations are ones that they share with teleosts.

11. Behavioural interactions in a vertebrate-dominated environment have probably been responsible for the vertebrate-type eye of cephalopods (p. 293).

12. The conclusion that the common adaptive zone shared by cephalopods and fish has been achieved by mutual interactions between the two groups evokes no special evolutionary principles. It assumes that all cephalopod species have (at some period of their evolutionary history) been in competition for food with some vertebrate species and that vertebrates are a source of selection pressures - largely operating through visual behaviour - that maintain and promote convergence upon the ‘fish’ modal type.

13. Selection pressures also operate within behaviour space to maintain and promote the special differences that separate any competitively successful species from all others. Coleoids as a group appear to have retained adaptations associated with such molluscan features as high growth rate and rapid turnover of the population. They are still characteristically crepuscular in habits and have extensive vertical mobility.

Cephalopods and fish: the limits of convergence

Since the latest Triassic, the Caribbean started to form as a system of rift valleys within westcentral Pangea, later evolving into a mediterranean sea where distinct volcanic and non-volcanic islands evolved. Since its very early formation, this sea has been playing an important role controlling the historical patterns of ocean water circulation, moderating the world climate, and determining the possibilities of biotic exchange of the surrounding terrestrial and marine ecosystems. The formation of a Mesozoic marine seaway between western Tethys and the eastern Pacific, across west-central Pangea, has been postulated for the Early Jurassic (Hettangian-Pliensbachian) according to biogeographic considerations, but supporting stratigraphic data are lacking. Probably since the Bathonian but certainly since the Oxfordian, the stratigraphic record indicates that this connection was fully functional and the Circum-Tropical marine current was active. Overland dispersal between western Laurasia (North America) and...

Meso-Cenozoic Caribbean Paleogeography: Implications for the Historical Biogeography of the Region

Introduction Part I. Time Scales: 1. Numerical time scale in 1989 2. Magnetic polarity time scale Part II. Circum-Pacific Base Map: 3. Reconstruction of the circum-Pacific region Part III. Regional Geology and Stratigraphy: 4. Western Canada and United States 5. Meso-America 6. Western South America 7. Australasia 8. Indonesia 9. Southeast Asia and Japan 10. Eastern China 11. Eastern Soviet Union Part IV. Chronostratigraphy, Index and Guide Fossils: 12. Ammonite zones of the circum-Pacific region 13. Palynomorphs in the circum-Pacific region 14. Radiolarian biozones of North America and Japan 15. Ostracods of western Canada 16. Bivalve zones and assemblages of the circum-Pacific region 17. Belemnites of the Southwest Pacific Part V. Biogeography: 18. Macroflora of eastern Asia and other circum-Pacific regions 19. Ostracods and foraminifers of western interior North America 20. Ostracods of China 21. Corals of the circum-Pacific region 22. Brachiopods of the western Pacific 23. Belemnites of the circum-Pacific region 24. Ammonites of the circum-Pacific region 25. Fish of the circum-Pacific region 26. Marine reptiles of the circum-Pacific region 27. Climate and oceanography of the Pacific region Part VI. Atlas of Index and Guide Fossils.

The Jurassic of the circum-Pacific

The ammonoid fauna of the Kimmeridgian-Tithonian boundary beds of Mombasa, Kenya

Jurasico medio en el peru

The Norian Pine River Bridge Section, British Columbia, and the succession of Monotis

Form, structure and function of shell and siphuncle in coiled Mesozoic ammonoids

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