Baculites

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Baculites
Temporal range: 96–65 
Ma
 Upper Cretaceous to Lower Paleocene
Baculites fossils from South Dakota. Some still have traces of the original nacre (shells).
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: †Ammonoidea
Order: †Ammonitida
Suborder: †Ancyloceratina
Family: †Baculitidae
Genus: †Baculites
Lamarck, 1799
Type species
†Baculites vertebralis
Lamarck, 1801[1] vide Meek, 1876[2]
Species

See text

Baculites is an extinct genus of heteromorph

Lamarck in 1799.[3][4]

Shell anatomy

The adult shell of Baculites is generally straight and may be either smooth or with sinuous striae or ribbing that typically slant dorso-ventrally forward. The aperture likewise slopes to the front and has a sinuous margin. The venter is narrowly rounded to acute while the dorsum is more broad. The juvenile shell, found at the apex, is coiled in one or two whorls and described as minute, about 1 centimetre (0.39 in) in diameter. Adult Baculites ranged in size from about 7 centimetres (2.8 in) (Baculites larsoni) up to 2 metres (6.6 ft) in length.

As with other ammonites, the shell consisted of a series of camerae, or chambers, that were connected to the animal by a narrow tube called a siphuncle by which gas content and thereby buoyancy could be regulated in the same manner as Nautilus does today. The chambers are separated by walls called septa. The line where each septum meets the outer shell is called the suture or suture line. Like other true ammonites, Baculites have intricate suture patterns on their shells that can be used to identify different species.

North American Museum of Ancient Life
in Lehi, Utah.

One notable feature about Baculites is that the males may have been a third to a half the size of the females and may have had much lighter ribbing on the surface of the shell.

Orientation

The shell morphology of Baculites with slanted striations or ribbing, similarly slanted aperture, and more narrowly rounded to acute keel-like venter points to its having had a horizontal orientation in life as an adult. This same type of cross section is found in much earlier

nautiloids such as Bassleroceras and Clitendoceras from the Ordovician period, which can be shown to have had a horizontal orientation. In spite of this, some researchers have concluded that Baculites lived in a vertical orientation, head hanging straight down, since lacking an apical counterweight, movement was largely restricted to that direction. More recent research, notably by Gerd Westermann, has reaffirmed that at least some Baculites species in fact lived in a more or less horizontal orientation.[5]

Ecology

From shell isotope studies, it is thought that Baculites inhabited the middle part of the water column, not too close to either the bottom or surface of the ocean. In some rock deposits Baculites are common, and they are thought to have lived in great shoals. However, they are not known to occur so densely as to be rock-forming, as do certain other extinct, straight-shelled cephalopods (e.g.,

isopod inside the mouth).[7]

Convergent evolution

Baculites and related

orthocerid nautiloids mostly lived much earlier (common during the Paleozoic Era, possibly going extinct in the Early Cretaceous)[8] than Baculites (Late Cretaceous-Danian
only). The two types of fossils can be distinguished by many features, most obvious among which is the suture line: it is simple in orthocerid nautiloids and intricately folded in Baculites and related ammonoids.

Species distribution

Baculites specimen in the field; western South Dakota, Pierre Shale, Late Cretaceous. Part of the phragmocone (left) and part of the body chamber (right) are present.
Baculites showing sutures and remnant aragonite; western South Dakota, Late Cretaceous.
Baculites from the Late Cretaceous of Wyoming. The original aragonite of the outer conch and inner septa has dissolved away, leaving this articulated internal mold.

Cenomanian:

Baculites gracilis is known from the Cenomanian Britton Formation.

Turonian:

Baculites undulatus, from the upper Turonian of Europe.[9]

Campanian:

The lower part of the Campanian stage (Upper Cretaceous) in the Western Interior of North America has yielded Baculites gilberti, early B. perplexus, B. asperiformis, B. maclearni, and B. obtusus, followed temporally by late Baculites perplexus and then by Baculites scotti. The upper part of the upper Campanian has yielded, from older to younger, B. compressus, B. coneatus, B. reesidei. B. jenseni, and B. ellasi, followed sequentially in the lower Maastrictian by Baculites baculus, B. grandis, and B. clinolobatis.[10][11]

Baculites pacificum is known from the Campanian of Vancouver Island, British Columbia, and Baculites leopoliensis from the Upper Campanian of Europe.[12]

Maastrichtian/Danian:

The type species, Baculites vertebralis is from the upper Maastrichtian and Danian, and is one of the

K-Pg mass extinction event, albeit being restricted to the Danian.[3][13][14] Baculites anceps is also known from Europe, although only from the Upper Maastrichtian.[12]

Holotype of Baculites ovatus Say, 1820 from the Navesink Formation in Atlantic Highlands, New Jersey.

Baculites ovatus is known from the Maastrichtian deposits of Ripley Formation in McNairy County, Tennessee, and Severn Formation in Prince George's County, Maryland.[15]

Cultural significance

Baculites fossils are very brittle and almost always break. They are most commonly found broken in half or several pieces, usually along suture lines. Individual chambers found this way are sometimes referred to as "stone buffaloes" (due to their shapes), though the Native-American attribution typically given as part of the story behind the name is likely apocryphal.[clarification needed] The Blackfoot have oral traditions that tell a story of the Iniskimm (Buffalo Calling Stone). They are still in use today by Indigenous peoples.

Baculites ovatus, the first species of Baculites described in the Americas, was described by Thomas Say in 1820[16] from a single specimen from the Navesink Formation in Atlantic Highlands, New Jersey. The specimen was later illustrated by Samuel George Morton, who published an etching in 1828.[17] After the death of the specimen's owner, the Quaker scientist Reuben Haines III, in 1831, the specimen was lost for 180 years until it was rediscovered at Haines's home, the historic Wyck House, in 2017 by Matthew Halley.[18]

References

  1. ^ Lamarck, J. P. B. A. de M. de (1801): Systeme des Animaux sans vertebres. The author; Deterville, Paris, vii + 432 pp.
  2. ^ Meek, F. B. (1876): A report on the invertebrate Cretaceous and Tertiary fossils of the upper Missouri country. In Hayden,F. V. Report of the United States Geological Survey of the Territories, 9, lxiv + 629 pp., 45 pis
  3. ^
    ISBN 978-94-017-9633-0
    , retrieved 2024-02-13
  4. ^ Lamarck, J. P. B. A. de M. de (1799): Prodrome d'une nouvelle classification des coquilles. Mem. Soc. Hist. Nat.Paris, (1799), 63-90.
  5. ^ Westermann, G. E. G. (1996). Ammonoid life and habitat. In N. H. Landman, K. Tanabe, and R. A. Davis (editors), Ammonoid Paleobiology, pp. 607–707. New York: Plenum Press.
  6. S2CID 206530342
    .
  7. ISBN 978-1-4020-6806-5. Archived from the original (PDF) on September 12, 2013.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  8. ^ Doguzhaeva, Larisa (1994-01-01). "An Early Cretaceous orthocerid cephalopod from North-Western Caucasus". Palaeontology. 37: 889–899.
  9. ^ "Baculites undulatus d'Orbigny, 1847". crioceratites.free.fr. Archived from the original on February 13, 2024. Retrieved 2024-02-13.
  10. ^ "Ammonite Zones (International Stratigraphy Standards)". North American Research Group. Archived from the original on October 4, 2023.
  11. ^ "Baculitidae (Gill 1871)". Jdsamonites. Archived from the original on June 5, 2023.
  12. ^ a b "Baculitidae GILL 1871". www.ammonites.fr. Archived from the original on May 27, 2022.
  13. doi:10.37570/bgsd-2005-52-08
    . Retrieved 2024-02-13.
  14. ^ W. M. Jagt, John (2012-01-01). "Ammonieten uit het Laat-Krijt en Vroeg-Paleogeen van Limburg". Grondboor & Hamer. 66 (1): 154–183.
  15. ^ "Mesozoic_Cephalopods". earthphysicsteaching.homestead.com. Archived from the original on September 22, 2023. Retrieved 2024-02-13.
  16. ^ Say, Thomas (1820). "Observations on some species of Zoophytes, Shells, &c. principally fossil (part 2)". The American Journal of Science and Arts. 2: 34–45.
  17. ^ Morton, Samuel George (1828). "Description of the fossil shells which characterize the Atlantic Secondary Formation of New Jersey and Delaware; including four new species". Journal of the Academy of Natural Sciences of Philadelphia. 6: 72–90.
  18. S2CID 164642352
    .

Further reading

  • Arkell et al., 1957, Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geological Soc. of America, Univ of Kansas Press. R.C. Moore, (Ed)
  • W. A. Cobban and Hook, S. C. 1983 Mid-Cretaceous (Turonian) ammonite fauna from Fence Lake area of west-central New Mexico. Memoir 41, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
  • W. A. Cobban and Hook, S. C. 1979, Collignoniceras woollgari wooollgari (Mantell) ammonite fauna from Upper Cretaceous of Western Interior, United States. Memoir 37, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
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