Kielania tumula, Johnson, 2024

Johnson, Robert G., 2024, Devonian Harpetidae from the central and eastern Anti-Atlas, Morocco, Zootaxa 5450 (1), pp. 1-185 : 63-65

Kielania tumula n. sp.

Plate 16A–L

Diagnosis. Cephalon sub oval, widest (tr.) at alae. Axial furrows broad and shallow. No muscle insertion furrows at S2, S3 or S4, and S1 only shallow depression in axial furrow. Alar furrows almost effaced. Eye lobes barely inflated and eye ridge indistinct. Genal roll gently sloping. Brim convex and brim width ratio around 0.90. No caeca on brim, and perforations around outside of brim large and widely spaced. External rim tilted outwards with marginal band sloping under cephalon. In lateral view, internal rim only slightly concave and steeply declining to terminal spine.

Etymology. Tumulus, Latin for mound. Cephalon in lateral view has a mound-like shape.

Material and occurrence. Holotype: NHMUK It 29259, Pl. 16A–E , from a horizon some 11.5 m below the “ Dicranurus Couche ” exposed in the bed of Oued Agourizi , West of Jbel Ou-Driss near the village Iminwaseif ( Fig. 2B, Map 4, site 1), Ihandar Formation, Pragian, a partial cephalon . Paratype: NHMUK It 29260, Pl. 16F–L , from the type horizon and locality (site 2), cephalon and enrolled thorax .

Other material: K. aff. tumula, NHMUK It 29262, Pl. 36P–R , from an upper Pragian horizon, Ihandar Formation, Timerzit ( Fig. 2B, Map 10, site 5), dorsal exoskeleton of a partial cephalon; and NHMUK It 29261, from type horizon and locality ( Fig. 2B, Map 10, site 3), a partial cephalon lacking bisymmetry and not figured herein or included in the cladistic study .

Description. Sub oval cephalon, narrow genicranium, widest at alae. Glabella wide, not inset and bullet-shaped, with shallow axial furrows tapering slightly anteriorly. S1 shallow depression in axial furrow and no furrows at S2, S3 or S4. L1 not inflated and occipital furrow bowed anteriorly. Sculptural tubercles on occipital ring and occipital node fairly large, moderately inflated and at edge of anterior slope of occipital ring. Posterior border wide (tr.) compared with width (tr.) of occipital ring.

Genal area moderately broad, without tubercles or genal ridge. Alae laterally directed and alar furrows very shallow. Eye lobes oval and very small with three eye lenses, anterior and posterior lenses oval and central lens subcircular and very small. Course of inner margin of fringe across anterior of area barely convex. Anterior boss barely inflated, reaching down to girder and with preaxial furrows converging gently. Girder kink weak. Genal roll sloping gently anteriorly at around 450 and moderately steeply laterally at over 600 and in lateral view, fringe narrowing only slightly posterolaterally. Perforations on genal roll fine and not densely packed.

In lateral profile, brim convex and sloping almost as steeply as anterior boss, at around 350. In dorsal view, brim width (sag.) 28% of cephalic length (sag.). Standardised brim perforations fine at around 110 μm in diameter, and about same size as those on genal roll but more densely packed. External rim stout and slightly arched medially in anterior view. Marginal band near vertical and straight, with ridge at top and bottom. Slope of marginal band down under cephalon decreases laterally. Prolongations on holotype short (exsag.), just over 70% of cephalic length (sag.). Long genal spine carried on lower lamella. Internal rims curving adaxially and with tubercles on dorsal surface. Only a few segments of thorax known. Pygidium and hypostome not known.

Remarks. Kielania tumula , resembles the type species K. waageni Prantl & Přibyl (1953, Fig. K4 1-3), from the Prokop Limestone (Pragian), Praha-Malá Chuchle, Czech Republic which is refigured herein ( Pl. 58 A–F ). It differs, however, in having a less vaulted cephalon and a less steeply-sloping brim and genal roll; a glabella that is narrower and tapered anteriorly, rather than being subcylindrical as in the case of K. waageni ; perforations on the genal roll the same size as those on the brim, not bigger, and the brim is convex whereas that of K. waageni is straight.

The paratype has a broader genicranium, longer prolongations and an internal rim which curves much more strongly adaxially. Also, there is evidence of a straight eye ridge and caeca on the brim. As the surface of the genal area of the holotype and paratype are not well preserved, it is difficult to compare the holotype and paratype.

Kielania aff. tumula NHMUK It 29262 ( Pl. 36P–R ) differs from the holotype NHMUK it 29259 in having: a cephalon which is widest halfway between the alae and eye lobes, rather than at the alae; a glabella which is more tectiform; a genal roll that is more steeply-sloping anteriorly; and a brim which is wider (sag.), less steeply-sloping and straight in profile, rather than convex. Also, the brim has a lower brim width ratio and steepens more strongly on the prolongations.

Genus Helioharpes Přibyl & Vaněk (emend.), 1981.

Type species. Harpes perradiatus Richter & Richter 1943 , Lower Eifelian, from the Phacopidella (Denckmannites) micromma zone, Dechra-ait-Abdullah, Western Meseta, Morocco.

Emended Diagnosis. Cephalon not strongly vaulted and genicranium widest at alae. Glabella wholly or partly carinate and narrow (tr.), at S1 between 54% and 66% of length (sag.) of glabella anterior to S0. Eye lobes weakly inflated, genal area moderately wide, width (tr.) between 54% and 66% of length (exsag.). Brim sloping moderately steeply at between 210 and 300 and strong network of caeca across whole brim.

Discussion. Helioharpes was established in 1981 by Přibyl & Vaněk, but was reduced to a junior synonym of Harpes by Ebach and McNamara in 2002 and the author now reinstates the genus. In the original diagnosis of the genus, an important element and the basis for the name of the genus was the “radial ridges and pits forming polygonal network” on the brim. The radial arrangement of the caecal ridges on the brim of the type species are not present on the brims of the three other species originally assigned to the genus: H. pyranicus ( Barrois, 1866) , H. radians ( Richter, 1863) and H. transiens ( Barrande, 1872) , and is therefore not diagnostic of the genus. Helioharpes transiens has caeca on the brim but it does not form a radial pattern. The illustrative drawings of H. radians and H. pyranicus are not clear enough to determine the extent to which brim caeca is present although H. aff radians ( Erben 1950) does have brim caeca similar to H. perradiatus . As regards radial brim “pits”, H. radians is the only species to have such an arrangement and therefore radial brim “pits” also are not a genus diagnostic. The brim “pits” of H. perradiatus are difficult to determine as the holotype cannot be located and in the original description ( Richter & Richter, 1943), there is only a drawing (abb. 2) and a poor photograph (taf. 4, fig. 12–13) to rely on. In the case of H. aougili n. sp., the brim perforations, which are visible in the gaps between the caeca, are not aligned ( Pl. 17F ). Given similarity of the arrangement of the brim caeca of H. perradiatus with that of H. aougili n. sp., particularly immediately anterior to the girder ( Pl. 17D, E ), it is likely that the brim perforations of H. perradiatus also do not form a radial pattern.

The cladogram in Beech & Lamsdell’s (2021) cladistic study showed H. perradiatus as belonging to Harpes . Based on Beech & Lamsdell’s coding, it seems quite probable that the same misidentification that was made in Ebach and McNamara, 2002 has been made again, namely that the species coded is different to the H. perradiatus holotype and is one of the harpetid species from the Anti-Atlas.

Helioharpes is similar to Stoloharpes but has wider genicranidium, widest at the level of the alae rather than between eye and alae; a wider (tr.) posterior border, a more distinct preglabellar furrow and an occipital furrow that is medially straight rather than being bowed posteriorly. Also, Helioharpes has no girder kink, the course of the inner margin of the fringe across the anterior of the genal area is convex not straight, the brim does not slope so steeply and has pronounced caeca. On the prolongation the brim does not steepen so quickly and the internal rim slants abaxially before curving adaxially, rather than just curving adaxially as in the of Stoloharpes .

Helioharpes is also similar to Pinnuloharpes , but differs in having a less vaulted cephalon, more tapered prolongations, a strongly developed caecal network on the brim, no preglabellar field and a higher brim width ratio. In species of Eskoharpes , the prolongations are strongly tapering and have rims that meet and join 2/3 of the way down, rather than running side by side to join at the end. Also, the cephalon of Eskoharpes is more vaulted and the caeca on the brim much more developed.

The species of Helioharpes included in the study and their interspecies relationships are shown in Figs 9 , 10b . Species not included in the study are H. gracilis ( Münster, 1840) , H. koeneni Wedekind, 1914 , H. pyrenaicus ( Barrois,1866) and H. radians Richter, 1863 which pro tem are reassigned from Harpes . The range of the genus is from the lower Eifelian to the Eifelian-Givetian boundary.

Figures

FIGURE 9. Cladogram consensus of 636 trees with a 31 node collapse and each tree L = 1968, Ci = 12 and Ri =48

FIGURE 10a. Lioharpes and Maghroharpes from tree 1 of 60 found using seed 7

PLATE 16. A–L Kielania tumula n. sp., from a lower Pragian horizon, Ihandar Formation, Iminwasief, 4.6 km W of Jbel Ou- Driss (Fig. 2B, Map 4). A–E dorsal exoskeleton, thorax disarticulated and enrolled, holotype, NHMUK It 29259 (site 1). A, dorsal, B, lateral, C, anterior and E, posterior view. D, dorsal view of brim perforations. F–L dorsal exoskeleton, thorax disarticulated and enrolled, paratype, NHMUK It 29260 (site 2). F, dorsal, G, lateral, H, anterior and J, posterior view. I, dorsal view of brim perforations, K, lateral view of glabella (uncoated) and L, lateral view of eye lobe. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 17. A–K and M–P Helioharpes aougili n. sp., from an Eifelian horizon, El Otfal Formation, Tamgoute Bulgan, 11.6 km SWt of El Jorf (Fig. 2B, Map 6). A–K dorsal exoskeleton, pygidium missing, holotype, NHMUK It 29254 (site 16). A, dorsal, B, anterior and C, lateral view. D, dorsal view of brim proximal to girder across the anterior of genicranium, E, anterior view of perforations on brim and genal roll, F, dorsal view of brim perforations. G and H, lateral and dorsal view of eye lobe, respectively. I, dorsal view of cuticle on glabella and genal area. J and K, lateral and dorsal view of pleurae, respectively. M–P dorsal exoskeleton of cephalon only, paratype, NHMUK It 29255 (site 17). M, dorsal, N, lateral and O, anterior view. P, dorsal view of brim perforation. L, H. perradiatus, dorsal view of brim proximal to girder across the anterior of genicranium (reprint), Richter & Richter, 1943, abb 2. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 36. A–K Harpes igaouii n. sp., Ihandar Formation, Pragian-Emsian boundary. A–H dorsal exoskeleton of cephalon only, holotype, NHMUK It 29360, from coral NW of Jbel Ou-Driss (Fig. 2B, Map 4, site 5). A, dorsal, B, anterior and C, lateral view. D, dorsal anterior view of perforations on genal roll and brim. E, dorsal view of glabellar tubercles, F, dorsal view of brim perforations, G, lateral view of glabellar muscle insertion scars (uncoated) and H, lateral view of eye lobe (uncoated). I–K dorsal exoskeleton of cephalon and partial thorax, paratype, NHMUK It 29361, from Ceratocephala horizon, North Jbel Ou-Driss (Fig. 2B, Map 4, site 8). I, dorsal anterior lateral view (uncoated). J, ventral view of hypostome and K, lateral view of eye lobe (uncoated). L–O Harpes aff. igaouii, dorsal exoskeleton of cephalon only, NHMUK It 29362, from Fezna, “Struveaspis Couche”, El Otfal Formation, Eifelian.(Fig. 2B, Map 6, site 1). L, dorsal, M, lateral and N, anterior view. O, dorsal view of brim perforations. P–R Kielania aff. tumula, Ihandar Formation, upper Pragian (Fig. 2B, Map 10, Site 5) dorsal exoskeleton of a partial cephalon, NHMUK It 29262. P, dorsal, Q, anterior and R, lateral view. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 58.A –F Kielania waageni (Novák MS) Prantl and Přibyl, 1954 type horizon and locality Prokop Limestones (Pragian), Praha-Malá Chuchle, Czech Republic, dorsal exoskeleton of a partial cephalon Museum of Natural History, Prague, holotype No. L6141.A dorsal view, B lateral view, C anterior view, D anterolateral view, E anterodorsal view and F lateral view of girder and perforations on genal roll and brim. This specimen was illustrated by Prantl and Přibyl (1954, pl. 9 fig.2). G–J Helioharpes dorbignyanus (Barrande 1846) type horizon and locality Dvorce Limestones (Pragian), Praha-Brank (“Za Branickou skalou” locality), Czech Republic, dorsal exoskeleton of a partial cephalon Natural History Museum Prague, No. L12563; G dorsal view, H lateral view, I anterior view and J dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.