Fig 1.
(A-D) Specimen from the Liencres area, Spain (MB.E.8251) in apical, oral, lateral and posterior views. (E-H) Specimen from the Erwitte area, Germany (GSUB E3867) in apical, oral, lateral and posterior views. Scale bar equals 1 cm.
Fig 2.
Simplified palaeogeographic map of western Europe during the Late Cretaceous (modified after [30]).
Table 1.
Investigated traits, their function, and evolutionary significance.
Fig 3.
(A) Plating drawings (after specimen GSUB E3867) depicting the landmark configurations for the specific analyses. (B) Global shape variation, shown as wireframe graph. (C) Fluctuating asymmetry analysis. For FA analysis: red circles represent paired landmarks, green circles represent median landmarks.
Fig 4.
Variation in the projection of the labral plate.
(A) Weakly projecting, not covering the peristomal opening (GSUB E3847, Erwitte area, Germany), (B) strongly projecting, covering completely the peristomal opening (MB.E.8251, Liencres area, Spain). Scale bars equal 1 cm.
Fig 5.
Wireframe graphs show the shape changes from the mean shape (red) to shape changes associated within PC1 and PC2 with a negative and positive direction.
Fig 6.
Wireframe graphs show the shape changes from the mean shape (red) to shape changes associated within PC3 and PC4 with a negative and positive direction.
Fig 7.
Principal component analysis scatter plots.
(A) PC1 versus PC2. (B) PC1 versus PC3.
Fig 8.
Principal component analysis scatter plots.
(A) PC1 versus PC3. (B) PC2 versus PC3.
Fig 9.
Shape variation of the asymmetric and symmetric component.
Shape variation on PC1 for the population from the Liencres and the Erwitte area.
Table 2.
Procrustes ANOVA results for the populations from Erwitte and Liencres area.
Fig 10.
Variation in development of the subanal fasciole.
Bar charts indicating the percentage for the particular populations in (A) the development of the subanal fascioles, (B) the development of the projection of the labrum (Li = Liencres area; Er = Erwitte area; Gr = Grimberg).
Fig 11.
Photographs illustrating variation in development of the subanal fasciole.
(A) Not present (GSUB E3847, Erwitte area, Germany). (B) Incomplete (GSUB E3850, Erwitte area, Germany). (C) Protofasciole (BGR X 06195, Grimberg IV shaft, Germany). (D) Orthofasciole (MB.E.3873, Liencres area, Spain). Scale bars equal 0.5 cm.
Fig 12.
Development in the structure of periplastronal area and the interporiferous area of the paired petals.
(A) Granular periplastronal area (MB.E.8196, Liencres, Spain). (B) Subdivided interporiferous area of the paired petals (GSUB E3867, Erwitte area, Germany). Scale bars equal 0.5 cm.
Fig 13.
Bivariate scatter plot of the numbers of pore pairs against test length.
Table 3.
Results of the FA analysis considering the pore pair numbers.
Fig 14.
FA1 scores of the pore pairs numbers.
Bar charts of the FA scores (FA1 index) for pore counts of the anterior and the posterior paired petals of the Liencres and the Erwitte population.
Fig 15.
Sketches illustrating the variation in the periplastronal ambulacral plates.
(A-B) Conspicuous asymmetric development. (C-D) Symmetric development, with longer ambulacral plates (C) and shorter plates (D) next to the labrum (A: MB.E.8196, Liencres area, Spain; B: GSUB E3847, Erwitte area, Germany; C: GSUB E3867, Erwitte area, Germany; D: MB.E.8257, Liencres area, Spain). Scale bars equal 1 cm.