Pinnuloharpes haustrum, Johnson, 2024

Johnson, Robert G., 2024, Devonian Harpetidae from the central and eastern Anti-Atlas, Morocco, Zootaxa 5450 (1), pp. 1-185 : 90-91

Pinnuloharpes haustrum n. sp.

Plates 42A–M , 43A–B

Diagnosis. Genicranium strongly vaulted and narrow, width (tr.) 1.3 times length (sag.); preglabellar field wide, length (sag.) 16% of width (tr.); and preglabellar furrow bowed up in anterior view. Alae wide (tr.), 45% of glabella width (tr.) at S0, slightly wider than width (exsag.) of ala at axial furrow. Alar depression and faint genal ridge present. Eye lobes oval, inflated and anterior and posterior eye lenses of equal size. Genal roll sloping steeply anteriorly at ≈ 600 and laterally at ≈ 700. Brim narrow (sag.), 29% of cephalic length, and brim width ratio low, at 0.54. Marginal band near vertical anteriorly, increasingly sloping down under cephalon posterolaterally. Tubercles on occipital ring, posterior border, internal rims and marginal band, and fine pitting on glabella, genal areas, axial rings and pleurae.

Etymology. Latin for a scoop: inverted the exoskeleton of cephalon is scoop-like.

Material and occurrence. Holotype: NHMUK It 29341, Pl. 42A–F , from an upper Emsian horizon in an outcrop 10 km west of Ksar Lbour, ( Fig. 2B, Map 3, site 3), dorsal exoskeleton with pygidium enrolled . Paratype: NHMUK It 29342, Pl. 42G–M , from type locality and horizon ( Fig. 2B, Map 3, site 4), dorsal exoskeleton with pygidium enrolled . Paratype: NHMUK It 29345, Pls 42N–O , 43A–B , from upper Emsian horizon, Hamar Lahgdad ( Fig. 2B, Map 11, site 13), dorsal exoskeleton with pygidium enrolled .

Other material: Pinnuloharpes aff. haustrum : NHMUK It 29347 (1 and 2), Pl. 43C–L, M–P , respectively, both from Destombesina tafilaltensis horizon, at base of the Upper Emsian, ( Morzadec 2001), Hamar Laghdad ( Fig. 2B, Map 11, site 7). NHMUK It 29347 (1), dorsal exoskeleton enrolled; NHMUK 29347 (2), ventral exoskeleton.

Description. Cephalon ovoid in shape, widest just posterior to eye lobes. Genicranium narrow, widest at alae. Glabella inset, flanks tectiform. S1 very shallow and L1 not inflated. Axial furrow convex, converging weakly anteriorly. Preglabellar furrow bowed upwards in anterior view. Occipital furrow deep, medially straight in dorsal view, and very broad (sag.), broader than posterior border (exsag.). Occipital ring same width (sag.) as posterior border (exsag.) and, in lateral view, same height as glabella anterior to S0. Tubercles present on dorsal surface. Alae laterally directed, broad, width (tr.) same as length (exsag.) at axial furrow. Alar furrow shallow, well defined and alar depression present. Preglabella furrow wide; genal area with fine pits. Eye lobes oval, large (exsag.), ≈43% of width of glabella at S1, and inflated. Genal ridge present, and narrow eye ridge well defined. Anterior boss inflated and joined to glabella. Inner margin of fringe barely concave across anterior of genal areas.

Genal roll moderately steep anteriorly (60 o) and steep laterally (70 o). In lateral view, internal fringe narrowing strongly posterolaterally. Perforations smaller than on brim, and decrease in size away from girder. Girder moderately narrow.

Brim barely sloping, concave (sag.), straight laterally and with width (sag.) of 30% of cephalic length (sag.). Brim width ratio low, at 0.57, and brim perforations moderately large, with a diameter of just below 180µm. Light caeca across brim. Rim with fine tubercles on dorsal surface and marginal band straight, vertical anteriorly, sloping under cephalon posterolaterally and with tubercles but no ridges. Brim steepens quickly on prolongations.

Length (exsag.) of prolongations 93% of cephalic length (sag.). Internal and external rims curving adaxially. Internal rim concave in lateral view. Rims meet before joining at end of prolongations. Genal spine long, following curve of exterior rim. Internal rim with tubercles on dorsal surface. Extension to girder meeting internal rim 1/3 way down prolongations.

Thorax with at least 18 segments, widens posteriorly to 5 th segment, and then tapers posteriorly so that width (tr.) of last segment is about 45% of 5 th segment. Pitting on axial rings and pleurae. Pleural furrows narrow, shallow but well defined. Outer portion of pleurae straight, slanting slightly posteriorly to inner portion, and distal ends pointed.

Remarks. The eye lenses on each eye lobe of Pinnuloharpes haustrum are of the same size and the occipital furrow is deep but otherwise the species complies with the diagnostic characters set out in Table 5c.

Pinnuloharpes haustrum is similar to P. merzaneensis , but differs in having: a cephalon that is broadest close to eye lobes, not at the midpoint between eyes and alae; a genicranium and genal area which are over 10% narrower than those of P. merzaneensis ; a shallow but slightly more pronounced preglabellar furrow; L1 not inflated; no interalar ridges or furrows; a slightly weaker girder kink; larger brim perforations; brim width ratio around 0.52, 10% lower than that of P. merzaneensis ; and the external rims on the prolongations curved rather than straight, as in P. merzaneensis .

Pinnuloharpes haustrum is quite similar to the material included on pl. XII, figures 10–11 of Feist’s (1977) doctoral thesis, but it has no S1 furrow, eye ridge or caeca on the genal roll, and it has a much lower brim width ratio. Also, the inner margin of the fringe passes well away from the eye lobe, while in the case of the material described in the thesis, the inner margin of the fringe passes immediately below the eye lobe.

The ventral exoskeleton and hypostome of P. haustrum is unknown, but other material (NHMUK It. 29347 (1 and 2), designated as P. cf. haustrum ( Pl. 43 C–P ), does include a ventral exoskeleton with hypostome. This material is very similar to P. haustrum but differs in having: a cephalon that is widest a little further back at the midpoint between eye lobes and alae; a 5–15% wider (tr.) genicranium; a 20% wider (tr.) posterior border; a glabella that is anteriorly more rounded; a much deeper preglabellar furrow; a preaxial furrow depression; a well-defined eye ridge; an occipital node which has a CMO with four regularly-spaced perforations on dorsal surface ( Pl. 43J ); Laterally-directed alae are; deeper, well-defined alar furrows; a shallow interalar furrow; axial furrows effaced at junction of alae and L1; genal roll with caeca and finer perforations; the brim more steeply sloping; and in lateral view, the profile of the internal rim is straight, rather than concave as in P. haustrum .

The ventral exoskeleton of P. cf. haustrum ( Pl. 43M ) shows that the ventral surface of the rim is ridged and tuberculate ( Pl. 43P ), and the perforations on the ventral surface of the lower lamella ( Pl. 43I ) are finer than those on the dorsal surface of the upper lamella’s brim ( Pl. 43F ). The girder, which forms a narrow brim-like structure around the inside of the genicranium, has an embayment corresponding to the girder kink. The hypostome ( Pl. 43O ) has a large egg-shaped anterior lobe of the middle body, with a very short (sag.) posterior lobe. The lateral border, which is narrow anteriorly, broadens very slightly two-thirds of the way back, before narrowing again. Posterior border narrow; anterior border even narrower. Shoulders broad close to the anterior of the hypostome, lateral distal edge sloping abaxially. Surfaces are tubercle-free.

The occipital node with a CMO of four very fine perforations found on P. cf. haustrum ( Pl. 43J ), may have been present on all harpids, but they are rarely found even in the best preserved of specimens. The only other material presented in this paper with such an occipital node is that of P. hamarlaghdadensis (new material) ( Pl. 44E ) and Lioharpes scopulum ( Pl. 32L ). McNamara (2009) (text fig. 4) described such an occipital node on Globoharpes friendi .

Figures

PLATE 32. A–D Maghroharpes terridus n. sp., Ihandar Formation, Pragian, Maharch, dorsal exoskeleton, thorax and pygidium disarticulated, holotype, NHMUK It 29321 (Fig. 2B, Map 9, site 18). A, dorsal, B, lateral and C, posterior view. D, dorsal view of brim perforations. E–Q Lioharpes scopulum n. sp., Ihandar Formation, bou Lachrhal. E–L dorsal exoskeleton of cephalon only, holotype, NHMUK It 29279 (Fig. 2B, Map 9, site 14). E, Dorsal, F, lateral and G, anterior view. H, lateral view of glabella (uncoated), I, dorsal view of brim perforations. J, and K, dorsal and lateral view of eye lobe respectively. L, dorsal view of occipital node. M–Q dorsal exoskeletons of partial cephala only, from type locality and horizon, paratypes, NHMUK It 29280 (1 to 3) (Fig. 2B, Map 9, site 3). M–N NHMUK It 29280 (1). M, dorsal view and N, dorsal view of eye lobe. O–P NHMUK It 29280 (2). O, dorsal view and P, dorsal view of brim perforations. Q, NHMUK It 29280 (3), dorsal view. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 42. A–M Pinnuloharpes haustrum n. sp., upper Emsian, Ksar Lbour. A–F dorsal exoskeleton pygidium enrolled, holotype, NHMUK It 29341 (Fig. 2B, Map 3, site 3). A, dorsal, B, lateral and C, anterior view. D, and E, dorsal view of brim perforations and genal area sculpture respectively. G–M dorsal exoskeleton pygidium enrolled, paratype, NHMUK It 29342 (Fig. 2B, Map 3, site 4). G, dorsal, H, lateral and I, anterior view. J, lateral view of eye lobe (uncoated), K, anterior view of genal roll perforations and L, dorsal view of brim perforations. M, anterior view of marginal band. N–O Pinnuloharpes haustrum n. sp., upper Emsian, Hamar Laghdad, dorsal exoskeleton with pygidium enrolled, paratype, NHMUK It 29345 (Fig. 2B, Map 11, site 13). N, dorsal view. O, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 43. A–B Pinnuloharpes haustrum n. sp., upper Emsian, Hamar Laghdad, dorsal exoskeleton with pygidium enrolled, paratype, NHMUK It 29345 (Fig. 2B, Map 13, site 11). A, anterior and B, lateral view. C– P Pinnuloharpes aff. haustrum, from base of upper Emsian, Hamar Laghdad. C–L dorsal exoskeleton with thorax enrolled, NHMUK It 29347 (1) (Fig. 2B, Map 11, site 7). C, dorsal, D, lateral and E, anterior view. F, dorsal view of brim perforations, G, anterior view of external rim. H, I and J dorsal view of sculpture on dorsal surface of genal area, brim perforations and occipital node, respectively. K, anterior view of perforations on the genal roll and L dorsal view of eye lobe. M–P ventral exoskeleton of cephalon only, NHMUK It 29347 (2), from same site as NHMUK It 29347 (1). M, ventral and N, lateral view. O and P, ventral view of hypostome and external rim, respectively. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 44. A–M Pinnuloharpes hamarlaghdadensis (Cronier et al. 2018), from Hamar Laghdad, upper Emsian. A–F dorsal exoskeleton with pygidium enrolled, NHMUK It 29337 (Fig. 2B, Map 11, site 1) A, dorsal, B, anterior and C, lateral view. D, dorsal view of brim perforations, E, dorsal view of occipital node and F, lateral view of eye lobe. G–J dorsal exoskeleton of cephalon and 2 pleural segments of thorax, NHMUK It 29338 (Fig. 2B, Map 11, site 2) G, dorsal, H, lateral and I, anterior view. J, dorsal view of brim perforations. K–M dorsal exoskeleton with thorax disarticulated and pygidium absent, NHMUK It 29339 (Fig. 2B, Map 11, site 3) K, dorsal and I, anterior view. L, dorsal view of brim perforations and M, lateral view of distal ends of pleurae. Scale bars shown represent 1 cm unless otherwise indicated.