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Fig. 7 in Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco

Fig. 7. Stratigraphical distribution of the Early Carboniferous genera of the Goniatitidae, displaying the gap in the record that spans from the latest Tournaisian to the Middle Viséan.

Fig. 1 in Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco

Fig. 1. Ammonoid genus zones (right column) of the Early Carboniferous (Mississippian) with indication (bold characters) of the fauna described in this publication. Serp., Serpukhovian.

Fig. 16 in Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco

Fig. 16. Whorl width/ conch diameter and umbilical width/ conch diameter ratios of Muensteroceras quadriconstrictum sp. nov.

Fig. 12 in Palaeobiogeographic and evolutionary meaning of an early Late Tournaisian ammonoid fauna from the Tafilalt of Morocco

Fig. 12. Whorl width/conch diameter and umbilical width/conch diameter ratios of Triimitoceras epiwocklumeriforme sp. nov.

Fig. 6. Damesites sugata Forbes, 1846. A in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 6. Damesites sugata Forbes, 1846. A. UMUT MM 28661 from the middle Campanian in the Nio River, Nakagawa area, north Hokkaido. B. UMUT MM 28662 from the middle Campanian in the Nio River, Nakagawa area, north Hokkaido (all in median longitudinal section). A1. Unusually long septal neck, extending into the body chamber, showing locations of photo A2; its length is equivalent to the last cameral distance. A2. Anterior margin of the long septal neck, consisting of a nacreous layer. B1. Unusually long septal neck, extending into the body chamber, showing locations of photo B2; its length is equivalent to the last cameral distance. B2. Anterior margin of the long septal neck, consisting of a nacreous layer. Abbreviations: bc, body chamber; n, nacreous layer of septal neck; s, septum; sn, septal neck.

Fig. 2 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 2. Phyllopachyceras ezoense (Yokoyama, 1890). UMUT MM 28658 from the lower Campanian of the Nakanofutamata−zawa Creek, Haboro area, northwest Hokkaido (median longitudinal section). A. Occurrence of precursory siphuncular membranes in the rear part of the body chamber showing locations of photos B–D. B. Adoral end of the last septal neck, showing the outer conchiolin layer resting on the nacreous layer of the septal neck. C. Conchiolin membranes in the rear part of the body chamber, consisting of thinner inner and thicker outer layers. D. Adoral end of the conchiolin membranes in the body chamber, which consist only of the outer layer. Abbreviations: bc, body chamber; ic, inner conchiolin layer; n, nacreous layer of septal neck; s, septum; sn, septal neck; oc, outer conchiolin layer.

Fig. 1 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 1. Phyllopachyceras ezoense (Yokoyama, 1890). UMUT MM 28657 from the lower Campanian of the Nakanofutamata−zawa Creek, Haboro area, northwest Hokkaido (median longitudinal section). A. Occurrence of precursory siphuncular membranes in the rear part of the body chamber showing locations of photos B and C. B. Adoral end of the last septal neck, showing the outer conchiolin layer resting on the nacreous layer of the septal neck. C. Adoral portion of the conchiolin membranes in the body chamber, consisting of thinner inner and thicker outer layers. The outer layer consists of adorally tilted pillar−like units. Abbreviations: bc, body chamber; ic, inner conchiolin layer; n, nacreous layer of septal neck; oc, outer conchiolin layer; s, septum; sn, septal neck.

Fig. 5 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 5. Phyllopachyceras ezoense (Yokoyama, 1890). UMUT MM 28660. Same specimen as that in Fig. 4. A. Siphuncular tube at the beginning of the second whorl, consisting of inner and outer conchiolin layers. The ventral side is distinctly detached from the ventral shell wall at this stage. B. Closeup of the ventral side of the siphuncular tube in the third whorl, showing that the membranes branching from the outer layer are attached to the ventral shell wall. Abbreviations: ic, inner conchiolin layer; oc, outer conchiolin layer; s, septum; vw, ventral shell wall.

Fig. 7 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 7. Successive stages of formation of the septal neck−siphuncular complex in Phyllopachyceras ezoense. A. Stage before anterior migration of the body and development of invagination of the septal epithelium in median dorsoventral (A1) and transverse (A2) sections. B. Development of the invagination of the septal epithelium followed by the gradual migration of the circumsiphonal portion of the body in median dorsoventral (B1) and transverse (B2) sections. Inner and outer layers of the primary conchiolin membranes are secreted by the siphuncular and septal epithelia, respectively. C. Gradual migration of the body and subsequent secretion of the nacreous septum by the septal epithelium. The inner layer of the siphuncular wall is thickened by additional conchiolin membranes secreted by the siphuncular epithelium, and the siphuncular wall at the preceding septal neck region is partly calcified (auxiliary deposit); median dorsoventral (C1) and transverse (C2) sections. Arrows point to the adoral direction.

Fig. 4 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 4. Phyllopachyceras ezoense (Yokoyama, 1890). UMUT MM 28660 from the middle Campanian of the southern tributary in the Osousyunai Creek, Nakagawa area, northern Hokkaido (dorso−ventral cross section). A. Ventral side of the body chamber, showing the shape of the precursory siphuncular membranes that directly contact the outer shell wall and the locations of photos B–D. B–D. Precursory siphuncular membranes at the dorsal (B), ventrolateral (C) and ventral (D) sides. At every side, the membranes are made up of a thinner homogeneous inner layer and a thicker outer layer with pillar−like units. Abbreviations: bc, body chamber; ic, inner conchiolin layer; oc, outer conchiolin layer.

Fig. 3 in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 3. Phyllopachyceras ezoense (Yokoyama, 1890). UMUT MM 28659 from the lower Campanian of the Nakanofutamata−zawa Creek, Haboro area, northwest Hokkaido (median longitudinal section). A. Occurrence of precursory siphuncular membranes in the rear part of the body chamber showing location of photos B, C. The membranes have a length equivalent to that of the two last camerae. B, C. Anterior end and close−up of the conchiolin membranes. The inner layer disappears just before the adoral end, whereas the outer layer still exists. Abbreviations: bc, body chamber; ic, inner conchiolin layer; n, nacreous layer of septal neck; oc, outer conchiolin layer; s, septum; sn, septal neck.

Fig. 3 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 3. Measurements for analysing the ventral breakage of ammonoid shells. Lines A, B, and C are the reference lines: A, from the coiling centre to aperture; B, apertural marginal line of damage; C, adapical marginal line of damage. Shaded area indicates body chamber. The length and depth of the breakage were also measured.

Fig. 6 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 6. Position of ventral breakage in the shells of seven early Toarcian ammonoid genera. Specimens whose position of the aperture is uncertain are excluded. Arrows indicate the average of the estimated position of last septum. The living orientation of the shells is based on Westermann 1996). A. Dactylioceras. B. Fontanelliceras. C. Fuciniceras. D. Protogrammoceras. E. Paltarpites. F. Harpoceras. G. Cleviceras.

Fig. 5 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 5. Example of ventral breakage in the early Toarcian ammonoid from the Toyora area, preserved in the cast (A) and mould (B) of Protogrammoceras onoi Hirano, 1971, UMUT MM 31437, loc. 18 (for detailed locality information see Fig. 2). The white brackets indicate the position and extent of the breakage. Scale bars 10 mm.

Fig. 9 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 9. Frequency of occurrence of lethal ventral damage on ammonoid shells. Error bars represent 95% binomial confidence intervals. A. Lower Taxon Frequency for the specimens of 7 genera from the Toyora area (see also Table 1). B. Assemblage Frequency for the selected Mesozoic ammonoid samples from different ages and/or regions. * The number is based on near-complete shells.

Fig. 4 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 4. Examples of early Toarcian ammonoids with ventral breakage, from the Toyora area, Japan (for detailed locality information see Fig. 2). A. Cleviceras chrysanthemum (Yokoyama, 1904), UMUT MM 31431, loc. 8. B. Cleviceras sp., UMUT MM 31432, loc. 5. C. Dactylioceras helianthoides Yokoyama, 1904), UMUT MM 31433, loc. 10. D. Fontanelliceras fontanellense (Gemmellaro, 1885), UMUT MM 31434, loc. 10. E. Fuciniceras nakayamense (Matsumoto, 1947), UMUT MM 31435, loc. 3. F. Protogrammoceras onoi Hirano, 1971, UMUT MM 31436, loc. 10. The white brackets indicate the position and extent of the breakage. Scale bars 5 mm.

Fig. 8 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 8. Double logarithmic plots of breakage length and depth versus shell diameter. Regression lines with reduced major axis method. All seven genera were included.

Fig. 1. Early Jurassic map illustrating the previously studied areas for ventrally damaged ammonoids. 1 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 1. Early Jurassic map illustrating the previously studied areas for ventrally damaged ammonoids. 1, Dotternhausen, Germany (Taverne 2000; Klompmaker et al. 2009); 2, Lyme Regis, England (Andrew et al. 2010). The Toyora area was located in the northwestern part of the Panthalassa. Palaeogeographical map after Scotese (2001).

Fig. 7 in Low durophagous predation on Toarcian (Early Jurassic) ammonoids in the northwestern Panthalassa shelf basin

Fig. 7. Size distribution of ventrally intact and damaged early Toarcian ammonoid specimens from the Toyora area. Percentage represents the breakage frequency in each size class.