Eccaparadoxides pradoanus

Esteve, Jorge, 2014, Intraspecific variability in paradoxidid trilobites from the Purujosa trilobite assemblage (middle Cambrian, northeast Spain), Acta Palaeontologica Polonica 59 (1), pp. 215-240 : 237-238

Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860)

Figs. 2–5 , 7 , 8 , 11 .

For synonymy, see Dies Álvarez et al. 2010 with addition of the following:

v 1860 Paradoxides Pradoanus , n. sp.; Verneuil and Barrande in Prado et al. 1860: 526, pl. 6: 4–6.

1882 Paradoxides Pradoanus, Barrande ; Barrois 1882: 169

v 1935 Paradoxides pradoanus Verneuil and Barrande in Prado et al., 1860; Sampelayo 1935: pl. 17: 3.

v 1947 Paradoxides Pradoanus Verneuil and Barrande in Prado et al., 1860; Thoral 1947: 78.

1958 Paradoxides pradoanus Verneuil and Barrande in Prado et al., 1860; Lotze 1958: 731, 738.

1958 Eccaparadoxides? pradoanus (Barrande and Verneuil in Prado et al., 1860); Šnajdr 1958: 115.

1961 Paradoxides pradoanus Verneuil and Barrande in Prado et al., 1860; Sdzuy 1961: 326–330, pls. 17: 15, 16, 18: 1-28, 19: 1–18, 21: 13, 28: 15, 28: 2, 34: 1, text-fig. 26.

v par. 1986 Paradoxides (Eccaparadoxides)? pradoanus Verneuil and Barrande in Prado et al., 1860; Liñán and Gozalo 1986: 59, pls. 21: 8–12, 22: 1–3.

v 2008 Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860); Liñán et al. 2008: 40, fig. 20d.

v 2010 Eccaparadoxides mediterraneus ( Pompeckj, 1901) ; Dies Álvarez et al. 2010: 99–103, figs. 3A–G, 4A–I, 5A–D.

Type material: Lectotype (selected herein): EM 170 091 ( Fig. 7A ;

Prado et al. 1860: pl. 6: 1) from Sabedo (León, North Spain). Paralectotypes, include the following: EM 170 092, EM 170 093, EM 170 094,

EM 170 095, EM 170 096 and EM 170 097.

Type locality: Sabedo ; León, North Spain .

Type horizon: Oville Formation, Solenopleuropsis ribeiroi Biozone ,

Drumian Stage, Cambrian Series 3.

Emended diagnosis.—Species of Eccaparadoxides with width frontal area (ca. 20–25% wider than the glabellar length), moderate narrow posterior border (ca. 70–90% glabellar length), posterior facial branch of facial suture very short (ca. 5% glabellar length) the anterior facial branch of facial suture extends esxagitally along the side of the glabella for a short way, ocular lobe about 50% of glabellar length. Thorax having 16–18 segments in holaspid specimens and consisting of two morphotypes: homonomous (all pleural spines similar in shape) or heteronomous in three batches macro-microspinose or with regular pleural spines). Pleurae with short horizontal inner portion, fulcra absent in the posterior segments, short pleural furrow extending abaxially to the edge of the doublure piercing slightly the doublure; large pleural spines increase in length to the anterior part ca. 60% transverse width of segments) to rear part (ca. 80% segments width), posteriormost pleural spines (homonomous and heteronomous) flank pygidium but do not reach beyond the level of the pygidial end, narrow rachis (ca. 35% transverse width of segment). Pygidium sub-hexagonal in outline, small holaspids with or without two posterolateral spines and maximum width in the vertex of the sub-hexagon, large holaspids with vertex of the maximum width curved, with two well developed posteriolateral spines; rhachis triangular in outline with one axial ring sporadically recognizable, occasionally with a second poorly developed axial ring.

Description.—The lectotype is an articulated specimen with 13 thoracic segments with the thoracic rear part slightly flexed. The glabella show SO strongly curved forward and S1 strongly curved backward, S2 apparently not transglabellar (probably due to preservation), but sketched transglabellar by Verneuil and Barrande in Prado et al. (1860); S3 and S4 barely visible ( Fig. 7B ). The thorax is poorly preserved but shows the short horizontal inner part of each pleural segment and a poorly developed fulcrum. The paralectotype’s cranidia show the same features as those from the Purujosa trilobite assemblage, one of them ( Fig. 7C ) only bear two transglabellar furrows (S1 and S2) and the other cranidium has two discontinuous (S3 and S4) and S4 is fade. EM 170 094 and EM 170 095 ( Fig. 7E, F ) show the rear part of two specimens, the pleural spines are very large and the rhachis is narrow. The pygidium of EM 170 094 ( Fig. 7E ) has a low spinosity-degree and the maximum width is in the vertex. The specimen EM 170 096 ( Fig. 7G ) is a big pygidium with the typical shape of large pygidia where maximum wide, is curved not formed an angle.

Remarks.— Paralectotype EM 170 097 is not figured herein ( Fig. 7C–G ; Prado et al. 1860: pl. 6: 2–6). Verneuil and Barrande (1860) figured only one cranidium ( Prado et al. 1860: pl. 6: 2). However, the Verneuil and Barrande collection includes a second cranidium figured herein ( Fig. 7C ).

Stratigraphic and geographic range.—Southwest Sardinia ( Italy), base of the Cabitza Formation, middle Cambrian, corresponding to the upper Caesaraugustan to lowermost Languedocian of the Mediterranean chronostratigraphy ( Pillola et al. 2002). Iberian Chains (northeast Spain), Murero and Borobia formations. Cantabrian Mountains (northwest Spain), Oville Formation. In both areas the species is found in the Solenopleuropsis riberoi Biozone to the Solenopleuropsis thorali Biozone (upper Caesaraugustan to Languedocian; middle Cambrian). Montagne Noire, southern France: Levels B to F in the Ravin du Brian and Coulouma sections, corresponding to the upper Caesaraugustan to Languedocian of the Mediterranean chronostratigraphy ( Courtessole 1973; Álvaro and Vizcaïno 1998).

Figures

Fig. 2. Reconstruction of the cranidium (A) and two types of pygidia of paradoxidid trilobite Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860); with features measured on the dorsal view indicated type Eccaparadoxides mediterraneus (Pompeckj, 1901) pygidium (B) and type E. pradoanus (Verneuil and Barrande in Prado et al., 1860) pygidium (C), and reconstruction of the librigena (D). Abbreviations: α S1, angle of furrow 1; tr., transversal.

Fig. 3. Common patterns of glabellar furrows within the Purujosa trilobite assemblage, Solenopleuropsis thorali Biozone, middle Cambrian, Spain. A. Specimen with two transglabellar (S1 and S2), two discontinuous (S3 and S4), and a convergence of SO and S1. B. Specimen with two transglabellar furrows (S1 and S2), one discontinuous furrow (S3), and a convergence of SO and S1. C. Specimen with two transglabellar furrows (S1 normal and S2 shallow medially), two discontinuous (S3 and barely visible S4), and convergence of SO. D. Specimen with two transglabellar furrows (S1 normal and S2 shallow medially), two discontinuous (S3 and barely visible S4), without convergence of any furrow. E. Specimen with two straight transglabellar furrows (S1 and S2), S2 shallow medially, and a shallow S3. F. Specimen with only two straight transglabellar furrows (S1 and S2). These patterns are seen in the 95% of the specimens although it is likely that other patterns can be found. Note that the ornamentation is strong in A and weaker in D and absent in E and F.

Fig. 4. Cranidia of paradoxidid trilobite Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860) showing differently developed glabellar furrows and preservation patterns common in mudstone from the Purujosa trilobite assemblage, Solenopleuropsis thorali Biozone, middle Cambrian, Spain. A. Meraspid cranidium with one glabellar furrow and S2 barely visible, the arrow points to preglabellar field (MPZ2011/2). B. Meraspid cranidium with two glabellar furrows, the arrow points to preglabellar field, right arrow points to the exsagital extension of the anterior facial branch of facial suture which touch the side of the glabella (MPZ2011/3). C. Holaspid cranidium with two continuous glabellar furrows and one no continuous and convergence of SO and S1 (MPZ2011/4). D. Holaspid cranidium with two continuous glabellar furrow and convergence of S1 (MPZ2011/5). E. Holaspid cranidium with two continuous glabellar furrows and two barely visible discontinuous two glabellar furrow, SO and S1 almost without convergence, arrow points to the exsagital extension of the anterior facial branch of facial suture which touch the side of the glabella (MPZ2011/6). F. Holaspid cranidium with two continuous glabellar furrows and two barely discontinuous glabellar furrows; SO and S1 almost without convergence (MPZ2011/7).G. Holaspid cranidium with two glabellar furrows; SO and S1 almost without convergence, arrow points to the exsagital extension of the anterior facial branch of facial suture along the side of the glabella (MPZ2011/8). H. Holaspid cranidium with two continuous glabellar furrows and two discontinuous, SO and S1 convergent, arrow points the genal caeca (MPZ2011/9). All photographs are taken from latex casts and internal moulds covered by sublimated NH Cl.

Fig. 7. Paradoxidid trilobite Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860) from Sabedo, León province, Solenopleuropsis ribeiroi Biozone, middle Cambrian, Spain. A, B. Lectotypes. A. EM 170 091, fairly complete specimen with two transglabelar glabellar furrow and two weakly incised visible discontinuous furrows. Note convergence of SO and S1, S3, and S4. B. EM 170 091 in lateral view, showing the rear part of the thorax slightly flexed. C–G. Paralectotypes. C. EM 170 092, cranidium with two continuous glabellar furrows and slightly convergent SO and S1. D. EM 170 093, cranidium with two continuous glabellar furrows and two weakly developed discontinuos glabellar furrows. E. EM 170 094, rear part of the thorax with attached pygidium with low spinosity-degree. F. EM 170 095, rear part of the thorax showing large rear pleural spines flanking the pygidium.G. EM 170 096, isolated pygidium.All specimens are photographs taken from internal moulds covered by sublimated NH Cl. Scale bars 5 mm.

Fig. 8. Sequence between specimens of Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860) from the Purujosa trilobite assamblege, Solenopleuropsis thorali Biozone, middle Cambrian, Spain. A. MPZ2011/25, specimen with granules. B. MPZ2011/26, specimen with weakly developed granules. C. MPZ2011/27, specimen with barely visible granules. Whole specimens (A 1, B 1, C 1), enlargements (A 2, B 2, C 2). Scale bars 5 mm.

Fig. 11. Types of thoraxes in Eccaparadoxides pradoanus (Verneuil and Barrande in Prado et al., 1860) from the Purujosa trilobite assamblege, Solenopleuropsis thorali Biozone, middle Cambrian, Spain. A–C. Heteronomous thorax. D. Homonomous thorax. See text for explanation. Scale bars 5 mm.