(Colour online) Stratigraphic occurrence of Acadoparadoxides species and some index species of other trilobites in the lower part of the Brèche à Micmacca Member, Jbel Wawrmast Formation in the Tarhoucht area, Jbel Ougnate region, eastern Anti-Atlas, Morocco (based on data from Geyer & Vincent, 2015). Thickness in metres above the base of the Jbel Wawrmast Formation. Left column refers to rock colours (r/p -red or purple; blgr -blue-green; ygr -yellow-green; mgr -middle grey; gy -grey; b/w -buff/white). Lithologies: si -siltstone; f -fine-grained sandstone; m -medium-grained sandstone; c -coarse-grained sandstone; ccGconglomerate. Fossiliferous horizons with trilobite remains indicated to the left of the stratigraphic columns.

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... They conclude that the Spanish and Moroccan specimens examined in the study, and which have been assigned to at least six different species, are all referable to a single taxon, Acadoparadoxides mureroensis (Sdzuy, 1958). Consequently, the detailed biostratigraphic scenario and evolutionary development portrayed in Geyer & Vincent (2015; Fig. 1) is not ...

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... part of the Jbel Wawrmast Formation in the Tarhoucht area, eastern Anti-Atlas, and comparison with other sections in southern Morocco has been done by Geyer & Vincent (2015). This work not only shows the abrupt appearance of the genus Acadoparadoxides in nearly monofacial successions, but also illustrated a rapid diversification of this genus (Fig. ...

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... (Sdzuy, 1958) is recorded only in a short interval. There is finally a joint occurrence of Acadoparadoxides ovatopyge Geyer & Vincent, 2015, Acadoparadoxides nobilis Geyer, 1998, an unnamed species and possibly A. briareus Geyer, 1993 high in parasequence 3 (Figs 1, 2). Acadoparadoxides briareus and another, undescribed species are found higher in parasequences 2 and 1. ...

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... from sample horizon 'Level 4', an interval described as being '30 cm thick' at the Assemame quarry (see Fig. 2). Zamora et al. (2014) and Álvaro et al. (2018) figured a total of eight cranidia and ten pygidia of Acadoparadoxides from 'Level 4', reported as A. mureroensis (Álvaro et al. 2018, fig. 3). Of these, six pygidia ( Álvaro et al. 2018, fig. 17f, g, k-n) show characters typical of a species referred to as A. cf. mureroensis in Geyer & Vincent (2015). The remaining four pygidia ( Álvaro et al. 2018, fig. 17a, b, e, h) are typical for A. levisettii. The thorax with attached pygidium shown in Álvaro et al. (2018, fig. 17l) is again typical for A. cf. mureroensis, and the pygidium ...

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... a total of eight cranidia and ten pygidia of Acadoparadoxides from 'Level 4', reported as A. mureroensis (Álvaro et al. 2018, fig. 3). Of these, six pygidia ( Álvaro et al. 2018, fig. 17f, g, k-n) show characters typical of a species referred to as A. cf. mureroensis in Geyer & Vincent (2015). The remaining four pygidia ( Álvaro et al. 2018, fig. 17a, b, e, h) are typical for A. levisettii. The thorax with attached pygidium shown in Álvaro et al. (2018, fig. 17l) is again typical for A. cf. mureroensis, and the pygidium is distinct from the broader, parabolic outline of the pygidia known in A. levisettii and A. pampalius (see descriptions below). This suggests that an interval ...

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... et al. 2018, fig. 3). Of these, six pygidia ( Álvaro et al. 2018, fig. 17f, g, k-n) show characters typical of a species referred to as A. cf. mureroensis in Geyer & Vincent (2015). The remaining four pygidia ( Álvaro et al. 2018, fig. 17a, b, e, h) are typical for A. levisettii. The thorax with attached pygidium shown in Álvaro et al. (2018, fig. 17l) is again typical for A. cf. mureroensis, and the pygidium is distinct from the broader, parabolic outline of the pygidia known in A. levisettii and A. pampalius (see descriptions below). This suggests that an interval equivalent to the thin A. cf. mureroensis band known from Bou Tiouit in the Tarhoucht area was sampled at Assemame, ...

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... of both pygidial morphotypes occur at approximately metre 12 ( Fig. 1) and appear to indicate a limited stratigraphic overlap of both species. There is also seemingly a 'transitional phase' for these two species where no confident identification is possible for several of the specimens. Despite the transition in pygidial morphology, well-preserved cranidia of both species can be distinguished ...

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... those of A. levisettii. However, the pygidia of A. levisettii are distinguished by their stratigraphic occurrence from those of A. nobilis, which occur higher in the sections. This is confirmed by an interval in which this 'indented posterior margin morphotype' does not occur, although the rock succession is monofacial and richly fossiliferous ( Fig. 1). Despite their morphological similarity, the cranidia of A. nobilis can be distinguished from those of A. levisettii in having a more evenly expanding glabella (not detected in the morphometric measurements by Álvaro et al. 2018), an anterior border that expands less distinctly from the axial line to the facial suture and slightly ...

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... more convincingly, species with a very similar morphology such as A. pampalius and A. ovatopyge on the one hand, or A. levisettii and A. nobilis on the other, are separated stratigraphically by ranges of species that can be clearly differentiated. This is shown by the species' ranges in Figure 1. This close relationship of stratigraphic range and the succession of morphologically distinct sclerites of earlier named Acadoparadoxides species was not included in the study by Álvaro et al. (2018) as a test of their proposed synonymy of a number of species with A. mureroensis as they interpreted that taxon. ...

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... may be assumed. Although radiometric dates are lacking, sequence stratigraphic analysis (W. Heldmaier, unpub. Ph.D. thesis, Univ. Würzburg, 1998) suggests that the overall time of the Jbel Wawrmast Formation deposition was not short. The 'subzones' bracketed by the appearances of the different species of Acadoparadoxides in the Tarhoucht area ( Fig. 1) may be comparable to those recorded by the succession of the Bergeroniellinae that defines the Bergeroniellus micmacciformis, Bergeroniellus gurarii, Bergeroniellus asiaticus, Bergeroniaspis ornata and Bergeroniellus ketemensis zones and its additional subzones in the Botoman and lower Toyonian of the Siberian Platform (e.g. Astashkin ...

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... The material of A. mureroensis from Spain which the authors used to compare with the material from Morocco consisted of 'the type material of A. mureroensis [ : : : ] supplemented by 13 cranidia and 7 pygidia of the same species from the type locality' ( Álvaro et al. 2018, p. 4). However, only one of the specimens is figured (a pygidium in their fig. 15), and this is the only item from the online Supplementary Material whose catalogue number has been provided. For none of these specimens has the sampling level been provided. As we know from Lotze (1929) and Sdzuy (1961), the origin of the type material is vague, and its recorded origin ('Fp. 15') refers to an interval of at least 17 m ...

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... the box plots in some of the graphs are not inclusive so that the data presented are inconclusive in a strict sense. As an example, the dots for specimens in Álvaro et al. (2018, fig. 10a, c) are not included with two specimens and appear to be outliers (PC2 near ...

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... fact, the Moroccan specimens are affected by a rather complex deformation. In such case, several factors can limit the output of the morphometrics, including bending of the symmetry axis (e.g. Álvaro et al. 2018, fig. 16e: note the asymmetry of the frontal lobe) and compaction-related crushing of the carapaces (e.g. Álvaro et al. 2018, fig. 16a, c versus fig. 16e, f). Thus, without developing some new retrodeformation techniques, it is impossible to remove the effect of such complex deformation. The amount of variation added to the sample by the ...

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... fact, the Moroccan specimens are affected by a rather complex deformation. In such case, several factors can limit the output of the morphometrics, including bending of the symmetry axis (e.g. Álvaro et al. 2018, fig. 16e: note the asymmetry of the frontal lobe) and compaction-related crushing of the carapaces (e.g. Álvaro et al. 2018, fig. 16a, c versus fig. 16e, f). Thus, without developing some new retrodeformation techniques, it is impossible to remove the effect of such complex deformation. The amount of variation added to the sample by the deformation may be too high when the sample contains very similar specimens so that the original variation of the sample can be described as relatively ...

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... plasticity that is seen in 'convincingly identified' specimens of A. mureroensis is entirely based on specimens from Spain, and this fact is discussed in some detail below. By contrast, the specimens identified as 'Acadoparadoxides mureroensis' from the Assemame quarry exhibit a remarkably low amount of variation ( Álvaro et al. 2018, fig. 16) when compared with the morphological disparity of other species described by Geyer & Vincent (2015). This is obviously caused by the fact that only part of colour cycle/parasequence 3 was quarried at Assemame so that this fauna is equivalent to the fauna recorded in the upper part of cycle/parasequence 3 in the Tarhoucht area (see ...

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... comparisons between the species/forms of Acadoparadoxides from the eastern Anti-Atlas and a comprehensive table listing their characters and character states has been presented in Geyer & Vincent (2015, fig. 12). A brief differential characterization of these species and forms presented in the following paragraphs focuses on the characters of the cranidium and the ...

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... species of Acadoparadoxides discussed herein. The pygidium is distinctly sub-triangular with a slightly indented median part of the posterior margin and with a pygidial axis that is shorter than that in the other species described from Morocco. This pygidium clearly falls out of the cluster illustrated in the PCA plots of Álvaro et al. (2018, fig. ...

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... according to the label are from the same locality and stratum ('Fp. 15') and were certainly collected by Lotze along with the type material. One of these cranidia (Fig. 9f) is associated with a nicely preserved thoracic segment not mentioned by Sdzuy (1958Sdzuy ( , 1961. The same slab has a librigena (SMF X 1370e; figured by Sdzuy 1961, pl. 16, fig. 12; refigured in Fig. 9g), which represents the best preserved free cheek known from A. mureroensis if it actually belongs to the same ...

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... cranidia were figured by Sdzuy (1961, pl. 16, figs 7, 10, 11), but all are distinctly dorsoventrally flattened and mostly from the collective sample horizon 'Fp. 15'. An exception is specimen L3242 from the Münster University collection (Sdzuy, 1961, pl. 16, fig. 7), which is listed as originating from 'Fp. 7' (as well as cranidium L 3239, Sdzuy, 1961, pl. 16, fig. 3). These specimens came from level A8, which is well above the base of the occurrences of A. mureroensis in level A7 according to Sdzuy (1961, pp. 32, 33, fig. 10). Level 'Fp. 7' (= level A8) also yields specimens of Hamatolenus lotzei figured in Sdzuy (1961, pl. 11), including its holotype. In the Bou Tiouit section, this species has ...

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... is specimen L3242 from the Münster University collection (Sdzuy, 1961, pl. 16, fig. 7), which is listed as originating from 'Fp. 7' (as well as cranidium L 3239, Sdzuy, 1961, pl. 16, fig. 3). These specimens came from level A8, which is well above the base of the occurrences of A. mureroensis in level A7 according to Sdzuy (1961, pp. 32, 33, fig. 10). Level 'Fp. 7' (= level A8) also yields specimens of Hamatolenus lotzei figured in Sdzuy (1961, pl. 11), including its holotype. In the Bou Tiouit section, this species has its acme around the occurrence of A. ovatopyge, but the cranidia in Sdzuy (1961, pl. 16, figs 3, 7) appear to be distinctly different from those of A. ovatopyge. ...

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... at an angle of 24° relative to the length axis and suffered oblique rotational distortion, which is particularly visible on the left-hand side. By contrast, the pleural area on the right-hand side experienced a slight oblique distortion. This makes a confident reconstruction of the specimen's precise original size difficult. Sdzuy's (1958, pl. 1, fig. 13) original figure is retouched and does not show the precise morphology. The blackening of the matrix surrounding the specimen is not accurately done, and therefore seems to show small differences when compared with the unretouched margin (compare with Sdzuy 1961, pl. 17, fig. ...

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... any rate, it is puzzling why the reconstruction of A. mureroensis in Álvaro et al. (2018, fig. 4) shows distinct differences from the sclerites in the type series in both the cranidium and pygidium. The topotype pygidium selected in Álvaro et al. (2018, fig. 15) that served as the template for their reconstruction differs so much from the paratype refigured herein that it is obvious that not just a single species assignable to A. mureroensis occurs in the Rambla de Valdemiedes 1 section. Although the precise morphology of A. mureroensis is unknown to date, careful bed-to-bed sampling in the ...

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... the relatively few specimens figured. It is also noteworthy that A. mureroensis is mentioned in at least 38 different publications on the Cambrian in Spain, but only figured in about ten publications. In these publications, the specimens are often considerably distorted, although regarded as being typical of the species (e.g. Gozalo et al. 2007, fig. 1a, b), and the pygidia of this 'species' differ in their morphology so distinctly that they have been described as different 'morphotypes' explained by 'sexual dimorphism' (e.g. Gozalo et al. 2003). This assumption of a highly plastic morphology has allowed assignment of distinct sclerites to the same ...