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New paleocene sepiid coleoids (cephalopoda) from Egypt: evolutionary significance and origin of the sepiid 'rostrum'.

Košťák M, Jagt JW, Speijer RP, Stassen P, Steurbaut E - PLoS ONE (2013)

Bottom Line: The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene.These earliest known belosaepiids may have originated in the Tethyan Realm.From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geology and Palaeontology, Faculty of Science, Charles University, Prague, Czech Republic.

ABSTRACT
New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a 'rostrum-like' prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or 'rostrum-like' structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian-Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America.

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Palaeogeographical distribution of belosaepiids s. lat. (inclusive of the genus Hungarosaepia and the anomalosaepiid Anomalosaepia).(A) The first belosaepiid occurrence in the Middle/Late Paleocene (Selandian–Thanetian) in northeast Africa (asterisk: Aegyptosaepia lugeri n. gen., n. sp., Egypt) and possible migratory routes. (B) Palaeobiogeographical distribution of belosaepiids during the Early Eocene. 1. Belosaepia incurvata, Sind, western India (Early Eocene, Ypresian). 2. Belosaepia sp., southeast Turkey (Early Eocene, Ypresian). 3. Belosaepia ex gr. sepioidea, Belgium (Early Eocene, Ypresian). 4. Belosaepia ex gr. sepiidea, England (Early Eocene, Ypresian). 5. Belosaepia s. str., USA (Texas; Early Eocene, Ypresian). (C) Palaeobiogeographical distribution of belosaepiids during the Middle Eocene. 1. Belosaepia ex gr. sepioidea, France, England, Belgium, the Netherlands (Middle Eocene, Lutetian–Bartonian). 2. Belosaepia szoerenyii, Hungary (Middle Eocene, Lutetian). 3. Belosaepia sepioidea, southern Nigeria (Middle Eocene, Lutetian). 4. Belosaepia s. str., USA (Alabama, Louisiana , Texas), North Carolina (Anomalosaepia) (Middle Eocene, Lutetian–Bartonian). 5. Occurrence of ?belosaepiid in the Late Eocene, USA (northwest Washington). * Yellow arrows denote possible migratory routes. Palaeogeography corresponds to the Late Paleocene (Thanetian), Early to Middle Eocene. Maps have been based, schematised and modified from www.scotese.com and http//cpgeosystems.com (Ron Blakey).
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pone-0081180-g010: Palaeogeographical distribution of belosaepiids s. lat. (inclusive of the genus Hungarosaepia and the anomalosaepiid Anomalosaepia).(A) The first belosaepiid occurrence in the Middle/Late Paleocene (Selandian–Thanetian) in northeast Africa (asterisk: Aegyptosaepia lugeri n. gen., n. sp., Egypt) and possible migratory routes. (B) Palaeobiogeographical distribution of belosaepiids during the Early Eocene. 1. Belosaepia incurvata, Sind, western India (Early Eocene, Ypresian). 2. Belosaepia sp., southeast Turkey (Early Eocene, Ypresian). 3. Belosaepia ex gr. sepioidea, Belgium (Early Eocene, Ypresian). 4. Belosaepia ex gr. sepiidea, England (Early Eocene, Ypresian). 5. Belosaepia s. str., USA (Texas; Early Eocene, Ypresian). (C) Palaeobiogeographical distribution of belosaepiids during the Middle Eocene. 1. Belosaepia ex gr. sepioidea, France, England, Belgium, the Netherlands (Middle Eocene, Lutetian–Bartonian). 2. Belosaepia szoerenyii, Hungary (Middle Eocene, Lutetian). 3. Belosaepia sepioidea, southern Nigeria (Middle Eocene, Lutetian). 4. Belosaepia s. str., USA (Alabama, Louisiana , Texas), North Carolina (Anomalosaepia) (Middle Eocene, Lutetian–Bartonian). 5. Occurrence of ?belosaepiid in the Late Eocene, USA (northwest Washington). * Yellow arrows denote possible migratory routes. Palaeogeography corresponds to the Late Paleocene (Thanetian), Early to Middle Eocene. Maps have been based, schematised and modified from www.scotese.com and http//cpgeosystems.com (Ron Blakey).

Mentions: These specimens resemble the Eocene genus Anomalosaepia, which is known exclusively from North America [26,28] (Figure 10C). However, only the posterior portion is retained; despite this, the general morphological features, such as the prong and callus, correspond to this genus. Although anomalosaepiids, of which four species have been described to date (in which only the posterior part is known), resemble belosaepiids, a new family, Anomalosaepiidae [28], has been established on the basis of a unique mineralogy (i.e., both calcite and aragonite), microstructures and unusual guard morphology.


New paleocene sepiid coleoids (cephalopoda) from Egypt: evolutionary significance and origin of the sepiid 'rostrum'.

Košťák M, Jagt JW, Speijer RP, Stassen P, Steurbaut E - PLoS ONE (2013)

Palaeogeographical distribution of belosaepiids s. lat. (inclusive of the genus Hungarosaepia and the anomalosaepiid Anomalosaepia).(A) The first belosaepiid occurrence in the Middle/Late Paleocene (Selandian–Thanetian) in northeast Africa (asterisk: Aegyptosaepia lugeri n. gen., n. sp., Egypt) and possible migratory routes. (B) Palaeobiogeographical distribution of belosaepiids during the Early Eocene. 1. Belosaepia incurvata, Sind, western India (Early Eocene, Ypresian). 2. Belosaepia sp., southeast Turkey (Early Eocene, Ypresian). 3. Belosaepia ex gr. sepioidea, Belgium (Early Eocene, Ypresian). 4. Belosaepia ex gr. sepiidea, England (Early Eocene, Ypresian). 5. Belosaepia s. str., USA (Texas; Early Eocene, Ypresian). (C) Palaeobiogeographical distribution of belosaepiids during the Middle Eocene. 1. Belosaepia ex gr. sepioidea, France, England, Belgium, the Netherlands (Middle Eocene, Lutetian–Bartonian). 2. Belosaepia szoerenyii, Hungary (Middle Eocene, Lutetian). 3. Belosaepia sepioidea, southern Nigeria (Middle Eocene, Lutetian). 4. Belosaepia s. str., USA (Alabama, Louisiana , Texas), North Carolina (Anomalosaepia) (Middle Eocene, Lutetian–Bartonian). 5. Occurrence of ?belosaepiid in the Late Eocene, USA (northwest Washington). * Yellow arrows denote possible migratory routes. Palaeogeography corresponds to the Late Paleocene (Thanetian), Early to Middle Eocene. Maps have been based, schematised and modified from www.scotese.com and http//cpgeosystems.com (Ron Blakey).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3860988&req=5

pone-0081180-g010: Palaeogeographical distribution of belosaepiids s. lat. (inclusive of the genus Hungarosaepia and the anomalosaepiid Anomalosaepia).(A) The first belosaepiid occurrence in the Middle/Late Paleocene (Selandian–Thanetian) in northeast Africa (asterisk: Aegyptosaepia lugeri n. gen., n. sp., Egypt) and possible migratory routes. (B) Palaeobiogeographical distribution of belosaepiids during the Early Eocene. 1. Belosaepia incurvata, Sind, western India (Early Eocene, Ypresian). 2. Belosaepia sp., southeast Turkey (Early Eocene, Ypresian). 3. Belosaepia ex gr. sepioidea, Belgium (Early Eocene, Ypresian). 4. Belosaepia ex gr. sepiidea, England (Early Eocene, Ypresian). 5. Belosaepia s. str., USA (Texas; Early Eocene, Ypresian). (C) Palaeobiogeographical distribution of belosaepiids during the Middle Eocene. 1. Belosaepia ex gr. sepioidea, France, England, Belgium, the Netherlands (Middle Eocene, Lutetian–Bartonian). 2. Belosaepia szoerenyii, Hungary (Middle Eocene, Lutetian). 3. Belosaepia sepioidea, southern Nigeria (Middle Eocene, Lutetian). 4. Belosaepia s. str., USA (Alabama, Louisiana , Texas), North Carolina (Anomalosaepia) (Middle Eocene, Lutetian–Bartonian). 5. Occurrence of ?belosaepiid in the Late Eocene, USA (northwest Washington). * Yellow arrows denote possible migratory routes. Palaeogeography corresponds to the Late Paleocene (Thanetian), Early to Middle Eocene. Maps have been based, schematised and modified from www.scotese.com and http//cpgeosystems.com (Ron Blakey).
Mentions: These specimens resemble the Eocene genus Anomalosaepia, which is known exclusively from North America [26,28] (Figure 10C). However, only the posterior portion is retained; despite this, the general morphological features, such as the prong and callus, correspond to this genus. Although anomalosaepiids, of which four species have been described to date (in which only the posterior part is known), resemble belosaepiids, a new family, Anomalosaepiidae [28], has been established on the basis of a unique mineralogy (i.e., both calcite and aragonite), microstructures and unusual guard morphology.

Bottom Line: The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene.These earliest known belosaepiids may have originated in the Tethyan Realm.From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geology and Palaeontology, Faculty of Science, Charles University, Prague, Czech Republic.

ABSTRACT
New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a 'rostrum-like' prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or 'rostrum-like' structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian-Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America.

Show MeSH
Related in: MedlinePlus