Harpes oudris, Johnson, 2024

Johnson, Robert G., 2024, Devonian Harpetidae from the central and eastern Anti-Atlas, Morocco, Zootaxa 5450 (1), pp. 1-185 : 49-50

Harpes oudris n. sp.

Plate 2E–M

Diagnosis. Axial furrows are convex and deep, and preglabellar furrow well defined. Tubercles and faint caeca on genal area. Perforations on genal roll same as on brim. Brim is moderately steeply-sloping and brim width ratio is between 0.68 and 0.75. Dorsal surface of external rim overhangs marginal band and carries tubercles. Prolongations over 90% of cephalic length (sag.), extension of girder meeting internal rim about halfway down prolongation. Internal rim in lateral view strongly wave-like in profile and distal end of prolongation sharply upturned.

Etymology. Named after Jbel Ou-Driss, the type locality.

Material and occurrence. Holoptype: NHMUK It 29241, Pl. 2I–M , from Section 1, horizon 5, ( Fig. 6 ), El Otfal Formation, Eifelian, Jbel Ou-Driss ( Fig. 2B, Map 4, site 22), dorsal exoskeleton with thorax partially exposed. Paratype: NHMUK It 29323, Pl. 22K–M , from a lower Emsian horizon, Boutiskaouine Formation, Awhare, Iferd Nou Haouar ( Fig. 2B, Map 9, site 13), dorsal exoskeleton of partial cephalon. Paratype: NHMUK It 29240, Pl. 2E–H , from type horizon, site 21, dorsal exoskeleton with thorax enrolled .

Other material: H. cf. oudris . NHMUK It 29242, Pl. 6A–H , from horizon 4, Section 1 ( Fig. 6 ), El Otfal Formation, Jbel Ou-Driss ( Fig. 2B, Map 4, site 10), an articulated dorsal exoskeleton with thorax enrolled with ventral surfaces exposed on anterior half of cephalon.

Description. Cephalon ovoid with widest (tr.) point at mid-point between eye lobes and alae. Genicranium narrow, widest at posterior border. Glabella fairly broad, width (tr.) 75% of length (sag.) of glabella anterior of S0, and with rounded crest and tubercles but no pitting. S1 rising out of axial furrow, sloping backwards and curving around top of muscle insertion area. No furrows at S2, S3 or S4 and L1 inflated. Axial furrows converge strongly anteriorly at nearly 200 to axis and cross junction between alae and L1. Preglabellar furrow distinct and bowed upwards in anterior view. Occipital furrow deep, wide, wider than posterior border and straight in dorsal view. Occipital ring broad (sag.), broader than posterior border (exsag.) and same height in lateral view as glabella anterior to S0. Occipital node large, alae anterolaterally directed and large (tr.), over 35% of length (sag.) of glabella anterior to S0 and reaching around 70% of way across genal area. Alar furrow shallow, well-defined. Interalar furrow and ridge and alar depression present. Posterior border short (tr.), around 23% of width (tr.) of occipital ring. Preglabellar field narrow, length (sag.) around 17% of width (tr.).

Genal area narrow, width (tr.) about 50% of length (exsag.) with faint caeca and pits and tubercles. Genal ridge present and eye lobes cone-shaped, strongly inflated and large (exsag.), just under 40% of width (tr.) of glabella at S1. Visual surface close to inner margin of fringe with eye lobes extending to edge of axial furrow. Eyes with two lenses, each lens rectangle shape with rounded corners and of approximately same size, and no eye ridge. Course of inner margin of fringe across anterior of genal area, convex. Boss barely inflated and not reaching down to girder. No girder kink and girder moderately narrow. Genal role sloping gently anteriorly at around 470 and more steeply laterally at around 630. No caeca on genal roll. Perforations are approximately same diameter as those of brim.

Brim slightly concave (sag.), straight laterally, width (sag.) 30% of cephalic length (sag.) and sloping moderately steeply at around 22%. Brim width ratio around 0.75. Standardised brim perforations becoming finer away from girder towards the centre, where they have a standardised diameter of around 145μm. Light caeca reaching across brim. External rim stout with fine tubercles on dorsal surface. Marginal band near vertical, overhung by external rim and with tubercles. Prolongations moderately long (exsag.) at around 87% of cephalic length (sag.) with extension of brim steepening quickly to near vertical. In dorsal view, internal and external rims curve adaxially and in lateral view, profile of internal rim strongly wave-like. Tubercles on dorsal surface of internal rim, large row of perforations below; and genal spine short. Extension of girder meets internal rim halfway down prolongation.

Thorax with over 20 thoracic segments with no tubercles or pitting on axial rings. Pleural furrows broad (tr.), deep and u-shaped, and outer portion of pleurae straight with rounded distal ends.

Pygidium and hypostome not known.

Remarks. Harpes oudris lacks three genus diagnostic characters shown in Table 5a. Its brim width ratio is above the upper limit of 0.68, there are light caeca reaching across brim and the extension of the girder meets the internal rim halfway down the prolongation rather than one third of the way down.

Harpes oudris is similar to but differs from H. boudibensis in having faint caeca on genal areas; axial furrows that are convex rather than straight (reflecting on the difference in glabella outline) and a distinct preglabellar furrow. Alae and eye lobes more inflated and posterior border (tr.) shorter, 25% of width (tr.) of occipital ring rather than between 30% and 34% in the case of H. boudibensis . Glabella of H. oudris not joined to anterior boss, genal roll steeper anteriorly and perforations on genal roll same size as on brim, not smaller. Brim of H. oudris steeper and has light caeca reaching across it. Brim width ratio over 0.68, whereas that of H. boudibensis is under 0.55. Dorsal surface of rim has fine tubercles and overhangs marginal band. Prolongations of H. oudris are shorter and extension of girder meets internal rim halfway down prolongation, not a third of the way down. Harpes oudris has 20 to 24 thoracic segments, not the 27 of H. boudibensis , and pleural furrows are deeper.

H. cf. oudris ( Pl. 6 A-H) differs from H. oudris in having a gently convex brim, a brim width ratio which is just over 10% higher at 0.77, and an internal rim that, in lateral view, is straight rather than wave-like.

The H. cf. oudris material contains an exposed hypostome (see Pl. 6 F, E ) that differs from that of H. boudibensis (see Pl. 1H, I ) in having a well-defined middle furrow, with raised maculae on the posterior edge of the furrow. These do not appear to be present on the hypostome of H. boudibensis .

Figures

PLATE 1. A–Q Harpes boudibensis n. sp., El Otfal Formation, Eifelian. A–D, articulated dorsal exoskeleton, paratype, NHMUK It 29226, type locality horizon 1 (site 1). A, dorsal, B, lateral and C, anterior view. D, dorsal view of brim perforations. E–J, dorsal exoskeleton, pygidium enrolled, paratype, NHMUK It 29228, type locality, horizon 2 (site 5). E, anterior, F, dorsal and G, lateral view. H, ventral view of anterior part of cephalon, I, hypostome and J, dorsal view of brim perforations. K–Q, enrolled articulated dorsal exoskeleton, holotype, NHMUK It 29227, horizon 1, Section 2 (Fig. 7), Jbel Issoumour (Fig. 2B, Map 7, site 4). K, dorsal, L, anterior, M, lateral view, N, anterior dorsal view of genal roll and brim perforations, O, dorsal view of brim perforations, P, lateral dorsal view of eye lobe and muscle impression areas at S0, S1, S2 and S3, and Q, lateral view of eye lobe. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 2. A–D Harpes cf. boudibensis, from horizon 7, Section 1 (Fig. 6), El Otfal Formation, Eifelian, Jbel Ou-Driss (Fig. 2B, Map 4, site 11). An enrolled dorsal exoskeleton NHMUK It 29225. A, dorsal, B, lateral and C, anterior view. D, dorsal view of brim perforations. E–M Harpes oudris, from horizon 5, Section 1 (Fig. 6), El Otfal Formation, Eifelian, Jbel Ou-Driss (Fig. 2B, Map 4). E–H, enrolled dorsal exoskeleton, paratype, NHMUK It 29240 (site 21). E, dorsal, F, lateral and G, anterior view. H, dorsal view of brim perforations. I–M Harpes oudris, enrolled dorsal exoskeleton, holotype, NHMUK It 29241 (site 22). I, dorsal, J, lateral and K, anterior view. L, dorsal view of brim perforations and M, lateral view of eye lobe. Scale bars shown represent 1 cm unless otherwise indicated.

FIGURE 6. Section 1 Jbel Ou-Driss

PLATE 6. A–H Harpes cf. oudris, dorsal exoskeleton with ventral surfaces exposed on anterior half of cephalon, NHMUK It 29242; from El Otfal Formation, Eifelian, horizon 4, Section 1 (Fig. 6), Jbel Ou-Driss (Fig. 2B, Map 4, site 10). A, dorsal, B, anterior and C, lateral view. D, lateral view of glabella (uncoated) and muscle insertion scars, E, ventral view of anterior half of cephalon, F, ventral view of hypostome in place, G, ventral view of anterior of rim, H, dorsal view of brim perforations. I–N Harpes cf. lahceni, dorsal exoskeleton of partial cephalon only, NHMUK It 29235, from “Erbenochile Couche”, Timrhanrhart Formation, Emsian, 23.8 km SW of Foum Zguid (Fig. 2A, Map 2, site 6). I, dorsal, J, anterior and K, lateral view. L, dorsal view of brim perforations and M and N, dorsal and lateral view of eye lobe respectively. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 22. A–E Maghroharpes cf. 1 laatchanensis, Ihandar Formation, Pragian, Jbel el Otfal (Fig. 2B, Map 9, site 8), dorsal exoskeleton of partial cephalon, NHMUK It 29311. A, dorsal, B, anterior and C, lateral view. D and E, dorsal view of brim perforations and occipital node and tubercles, respectively. F–M Maghroharpes aff.1 minutipunctus, Boutiskaoine Formation? lower Emsian. F–J dorsal exoskeleton of partial cephalon, NHMUK It 29322, Jbel Ou-Driss (North) (Fig. 2B, Map 4, site 7). F, dorsal, G, anterior and H, lateral view. I, lateral and J, dorsal view of eye lobe. K–M dorsal exoskeleton of partial cephalon, paratype, NHMUK It 29323, Boutiskaouine Formation, lower Emsian, Ahware (Fig. 2B, Map 9, site 13). K, L and M, dorsal view of cephalon, brim perforations and eye lobe, respectively. N–Q Maghroharpes aff. 2 minutipunctus, Ihandar Formation Jbel Ou-Driss (West) (Fig. 2B, Map 4, site 20), dorsal exoskeleton of partial cephalon, NHMUK It 29324. N, dorsal, O, lateral and P, anterior view. Q, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.