Is the relative thickness of ammonoid septa influenced by ocean acidification, phylogenetic relationships and palaeogeographic position?

Swiss Journal of Palaeontology

Table 7 States of four abiotic factors correlated with age midpoint (average of ages of the beginning and the end of the corresponding stages after international chronostratigraphic chart from stratigraphy.org) and septal slope factor of ontogenetic trajectory of septal thickness through the Mesozoic. Palaeoenvironmental data are from Berner (2006): CO₂, Demicco et al. (2005): Mg/Ca ratio, [Ca²⁺] (mol mol⁻¹), and Ridgwell (2005): Sea surface pH

Species	Age midpoint (Ma) Cohen et al. (2013)	Septal slope factor (this study)	CO₂ (ppm) Berner et al. (2006)	CO₂ (ppm) Berner et al. (2006)	Mg/Ca ratio (mol mol⁻¹) Demicco et al. (2005)	[Ca²⁺] (mol mol⁻¹) Demicco et al. (2005)	Sea surface pH Ridgwell (2005)
Desmoceras	105.5	0.0078	1650	1033.87	0.6	5.15	7.55
Cleoniceras	105.5	0.0028	1650	1033.87	0.6	5.15	7.55
Gaudryceras	105.5	0.0124	1650	1033.87	0.6	5.15	7.55
Argonauticeras	105.5	0.0107	1650	1033.87	0.6	5.15	7.55
Eogaudryceras umbilicostriatus	106.75	0.004	1700	1033.87	0.6	5.15	7.55
Divisosphinctes	154.3	0.0037	2430	693.66	1.45	3.5	7.62
Macrocephalites compressus	168.8	0.0041	2430	875.22	1.45	3.5	7.62
Ludwigia	172.2	0.0024	2200	963.28	1.51	3.3	7.62
Staufenia	172.2	0.0004	2200	963.28	1.51	3.3	7.62
Leioceras	176.5	0.001	1950	963.28	1.52	3.25	7.6
Dactylioceras	178.4	0.0027	1800	963.28	1.53	3.2	7.57
Lytoceras	187.7	0.0067	1650	645.87	1.9	2.9	7.54
Asteroceras	195.05	0.0019	1550	870.46	2.4	2.5	7.52
Arietites	195.05	0.0012	1550	870.46	2.4	2.5	7.52
Fuciniceras	195.05	0.0064	1550	870.46	2.4	2.5	7.52
Schlotheimia	196.1	0.0036	1500	870.46	2.45	2.45	7.52
Psiloceras planorbis	200.3	0.0047	1100	870.46	2.7	2.3	7.58
Psiloceras naumanni	200.3	0.0034	1100	870.46	2.7	2.3	7.58
Arcestes	222.8	0.0048	700	1216.61	2.7	2.2	7.7
Halorites	226.6	0.0098	750	1216.61	2.6	2.3	7.73
Cladiscites	226.6	0.0147	750	1216.61	2.6	2.3	7.73
Discophyllites	226.6	0.0077	750	1216.61	2.6	2.3	7.73
Megaphyllites	226.6	0.0054	750	1216.61	2.6	2.3	7.73
Monophyllites	226.6	0.0067	750	1216.61	2.6	2.3	7.73
Rhacophyllites neojurensis	226.6	0.0075	750	1216.61	2.6	2.3	7.73