The decapod crustaceans from the Late Cretaceous (Cenomanian) of Lebanon were subject of studies ... more The decapod crustaceans from the Late Cretaceous (Cenomanian) of Lebanon were subject of studies by Brocchi (1875), Dames (1886), Roger (1946), Glaessner (1945), Garassino (1994, 2001), and Larghi (2004). The recent discovery of two specimens from Hadjula and Sahel-Alma quarries, belonging to Cretasergestes sahelalmaensis n. gen., n. sp. (superfamily Sergestoidea Dana, 1852, family Sergestidae Dana, 1852) and Cancrinos libanensis n. sp. (infraorder Palinura, Latreille, 1802, family'Cancrinidae Beurlen, 1930) extends the stratigraphic range of the family Sergestidae, previously known only from the Early Cretaceous (Aptian-Albian) of Brazil and Cancrinos Minister, 1839, previously known only from the Late Jurassic (Tithonian) of Solnhofen and Eichstatt (Germany), into the Cenomanian.
The reptant decapod Malmuncina wulfi n. g. n. sp. is the hitherto youngest representative of Unci... more The reptant decapod Malmuncina wulfi n. g. n. sp. is the hitherto youngest representative of Uncinidae, formerly only known from the Lower Jurassic. It is recorded from Upper Jurassic lithographic limestones of southern Franconia (Breitenhill, Zandt, Eichstätt).
New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boun... more New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0...
FIG. 7. — The oldest example of heterochelous paguroid claws from the Upper Jurassic of the Wimer... more FIG. 7. — The oldest example of heterochelous paguroid claws from the Upper Jurassic of the Wimereux area (Boulonnais, northwestern France); an individual preserved in situ in the internal mould of a Vetigastropoda (private collection of Mr Gilles Dron). The maximum diameter of the gastropod is about 7 cm.
FIG. 3. — Reduction of rostral length during the Late Jurassic in representatives of the families... more FIG. 3. — Reduction of rostral length during the Late Jurassic in representatives of the families Gastrodoridae (A), Parapylochelidae (B) and Pylochelidae (C).
FIG. 11. — Paguropsids (Paguropsidae n. fam) through time, from the Oxfordian Eopaguropsis Fraaij... more FIG. 11. — Paguropsids (Paguropsidae n. fam) through time, from the Oxfordian Eopaguropsis Fraaije, Krzemiński, Van Bakel. Krzemińska & Jagt, 2012 (A), via the Tithonian Eopaguropsis (B) to extant Paguropsis Lemaitre, Rahayu & Komai, 2018 (C).
FIG. 6. — Isochelous chelae of paguroids from the middle Callovian of Poitou, France: A, specimen... more FIG. 6. — Isochelous chelae of paguroids from the middle Callovian of Poitou, France: A, specimen UP/CGL.12.10 (UP = Université de Poitiers, CGL = Calcaires de Gratte-Loup). B, specimen UP/CGL.12.11. Photographs: Philippe Loubry. Scale bars: 10 mm.
FIG. 2. — Branchial condensation in representatives of the families Parapylochelidae (A, B), Gast... more FIG. 2. — Branchial condensation in representatives of the families Parapylochelidae (A, B), Gastrodoridae (C), Xylopaguridae (D, E) and Pylojacquesidae (F).
The Muensterelloidea is a superfamily of teudopseid octobrachians with a posteriorly patella-shap... more The Muensterelloidea is a superfamily of teudopseid octobrachians with a posteriorly patella-shaped gladius. A morphometric comparison based on 148 muensterelloid gladii has yielded five new species accommodated in three new genera: Engeseriteuthis arcuatus gen. nov. sp. nov., Muensterella jillae sp. nov., Muensterella spinosa sp. nov., Tyrionella fauseri gen. nov. sp. nov., and Muensterellina johnjagti gen. nov. sp. nov. Cretaceous taxa “Tusoteuthis” cobbani and “Muensterella” tonii are re-combined and placed within the genus Enchoteuthis. We introduce categories for gladius proportions applicable for both muensterelloid and non-muensterelloid octobrachian gladii. 2D-landmark analyses including 64 muensterelloid and non-muensterelloid gladii statistically confirms that the Muensterelloidea possess the smallest median field sizes of all Mesozoic gladii. The lateral field-dominated “gladius” of the family Patelloctopodidae (Patelloctopus, Pearceiteuthis) is considered to be vestigial; i.e. shorter than the mantle length; a view that expose the Patelloctopodidae as the last shared ancestors of incirrate and cirrate octopods. According to a phylogenetic analysis based on 31 gladius characters, the Muensterelloidea mainly consists of the “Muensterella-Enchoteuthidae” and the “patelloctopodid” clade. Ancestral character state reconstructions suggest that an increasing posterior growth front is accompanied by a continuous decrease of the median field length. This milestone in the evolution of the octopod gladius vestige occurred between the Early and Middle Jurassic. The benthic life style of incirrate octopods (including Cretaceous palaeoctopodids) has been adopted from Jurassic Patelloctopodidae, which itself arose from nectonic to nectobenthic teudopseid ancestors. There is currently no evidence to assume a pelagic origin for benthic octopods
The decapod crustaceans from the Late Cretaceous (Cenomanian) of Lebanon were subject of studies ... more The decapod crustaceans from the Late Cretaceous (Cenomanian) of Lebanon were subject of studies by Brocchi (1875), Dames (1886), Roger (1946), Glaessner (1945), Garassino (1994, 2001), and Larghi (2004). The recent discovery of two specimens from Hadjula and Sahel-Alma quarries, belonging to Cretasergestes sahelalmaensis n. gen., n. sp. (superfamily Sergestoidea Dana, 1852, family Sergestidae Dana, 1852) and Cancrinos libanensis n. sp. (infraorder Palinura, Latreille, 1802, family'Cancrinidae Beurlen, 1930) extends the stratigraphic range of the family Sergestidae, previously known only from the Early Cretaceous (Aptian-Albian) of Brazil and Cancrinos Minister, 1839, previously known only from the Late Jurassic (Tithonian) of Solnhofen and Eichstatt (Germany), into the Cenomanian.
The reptant decapod Malmuncina wulfi n. g. n. sp. is the hitherto youngest representative of Unci... more The reptant decapod Malmuncina wulfi n. g. n. sp. is the hitherto youngest representative of Uncinidae, formerly only known from the Lower Jurassic. It is recorded from Upper Jurassic lithographic limestones of southern Franconia (Breitenhill, Zandt, Eichstätt).
New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boun... more New data are presented in relation to the worldwide definition of the Oxfordian/Kimmeridgian boundary, i.e. the base of the Kimmeridgian Stage. This data, mostly acquired in the past decade, supports the 2006 proposal to make the uniform boundary of the stages in the Flodigarry section at Staffin Bay on the Isle of Skye, northern Scotland. This boundary is based on the Subboreal-Boreal ammonite successions, and it is distinguished by the Pictonia flodigarriensis horizon at the base of the Subboreal Baylei Zone, and which corresponds precisely to the base of the Boreal Bauhini Zone. The boundary lies in the 0.16 m interval (1.24–1.08 m) below bed 36 in sections F6 at Flodigarry and it is thus proposed as the GSSP for the Oxfordian/Kimmeridgian boundary. This boundary is recognized also by other stratigraphical data – palaeontological, geochemical and palaeomagnetic (including its well documented position close to the boundary between magnetozones F3n, and F3r which is placed in the 0...
FIG. 7. — The oldest example of heterochelous paguroid claws from the Upper Jurassic of the Wimer... more FIG. 7. — The oldest example of heterochelous paguroid claws from the Upper Jurassic of the Wimereux area (Boulonnais, northwestern France); an individual preserved in situ in the internal mould of a Vetigastropoda (private collection of Mr Gilles Dron). The maximum diameter of the gastropod is about 7 cm.
FIG. 3. — Reduction of rostral length during the Late Jurassic in representatives of the families... more FIG. 3. — Reduction of rostral length during the Late Jurassic in representatives of the families Gastrodoridae (A), Parapylochelidae (B) and Pylochelidae (C).
FIG. 11. — Paguropsids (Paguropsidae n. fam) through time, from the Oxfordian Eopaguropsis Fraaij... more FIG. 11. — Paguropsids (Paguropsidae n. fam) through time, from the Oxfordian Eopaguropsis Fraaije, Krzemiński, Van Bakel. Krzemińska & Jagt, 2012 (A), via the Tithonian Eopaguropsis (B) to extant Paguropsis Lemaitre, Rahayu & Komai, 2018 (C).
FIG. 6. — Isochelous chelae of paguroids from the middle Callovian of Poitou, France: A, specimen... more FIG. 6. — Isochelous chelae of paguroids from the middle Callovian of Poitou, France: A, specimen UP/CGL.12.10 (UP = Université de Poitiers, CGL = Calcaires de Gratte-Loup). B, specimen UP/CGL.12.11. Photographs: Philippe Loubry. Scale bars: 10 mm.
FIG. 2. — Branchial condensation in representatives of the families Parapylochelidae (A, B), Gast... more FIG. 2. — Branchial condensation in representatives of the families Parapylochelidae (A, B), Gastrodoridae (C), Xylopaguridae (D, E) and Pylojacquesidae (F).
The Muensterelloidea is a superfamily of teudopseid octobrachians with a posteriorly patella-shap... more The Muensterelloidea is a superfamily of teudopseid octobrachians with a posteriorly patella-shaped gladius. A morphometric comparison based on 148 muensterelloid gladii has yielded five new species accommodated in three new genera: Engeseriteuthis arcuatus gen. nov. sp. nov., Muensterella jillae sp. nov., Muensterella spinosa sp. nov., Tyrionella fauseri gen. nov. sp. nov., and Muensterellina johnjagti gen. nov. sp. nov. Cretaceous taxa “Tusoteuthis” cobbani and “Muensterella” tonii are re-combined and placed within the genus Enchoteuthis. We introduce categories for gladius proportions applicable for both muensterelloid and non-muensterelloid octobrachian gladii. 2D-landmark analyses including 64 muensterelloid and non-muensterelloid gladii statistically confirms that the Muensterelloidea possess the smallest median field sizes of all Mesozoic gladii. The lateral field-dominated “gladius” of the family Patelloctopodidae (Patelloctopus, Pearceiteuthis) is considered to be vestigial; i.e. shorter than the mantle length; a view that expose the Patelloctopodidae as the last shared ancestors of incirrate and cirrate octopods. According to a phylogenetic analysis based on 31 gladius characters, the Muensterelloidea mainly consists of the “Muensterella-Enchoteuthidae” and the “patelloctopodid” clade. Ancestral character state reconstructions suggest that an increasing posterior growth front is accompanied by a continuous decrease of the median field length. This milestone in the evolution of the octopod gladius vestige occurred between the Early and Middle Jurassic. The benthic life style of incirrate octopods (including Cretaceous palaeoctopodids) has been adopted from Jurassic Patelloctopodidae, which itself arose from nectonic to nectobenthic teudopseid ancestors. There is currently no evidence to assume a pelagic origin for benthic octopods
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