Maghroharpes forteyi, Johnson, 2024

Johnson, Robert G., 2024, Devonian Harpetidae from the central and eastern Anti-Atlas, Morocco, Zootaxa 5450 (1), pp. 1-185 : 81-83

Maghroharpes forteyi n. sp.

Plate 29A–D, K–N

Diagnosis. Cephalon nearly ovoid; genicranium moderately vaulted; genal roll without caeca and sloping gently anteriorly and laterally. Glabella narrow, very strongly vaulted, inset and with fine tubercles and pitting. Axial furrows deep and straight; preglabellar furrows bowed upwards in anterior view; and preaxial furrows forming circular depressions across inner margin of fringe. Occipital ring higher than glabella anterior to S0. Genal area very narrow, and genal ridges present. Eye tubercles tall, with three lenses and fine tubercles and pits on dorsal surface. Brim width ratio high, at 0.87.

Etymology. For Richard Fortey, without whose advice and support this paper would not have been written.

Material and occurrence. Holotype: NHMUK It 29288, Pl. 29A–D , from a horizon at or near the “Couche Rouge” horizon at the top of the Pragian, Ihandar Formation, Azmamar, Oued el Atchane, Jbel Oufatene ( Fig. 2B, Map 8, site 16), dorsal exoskeleton of cephalon only . Paratype: NHMUK It 29289, Pl. 29K–N , from horizon close to the top of the Pragian, Ihandar Formation, Jbel Otfal ( Fig. 2B, Map 9, site 7), dorsal exoskeleton of a partial cephalon .

Other material: Maghroharpes cf. forteyi, NHMUK It 29284, Pl. 31F–K , from type horizon and location ( Fig. 2B, Map 8, site 20), dorsal exoskeleton of cephalon only.

The material from both the above localities was found in small coral and stromatoporoid colonies with a lateral exposure of around 4 metres.

Description. Cephalon ovoid, widest at anterior of alae; genicranium narrow, width (tr.) 1.3 times length (sag.), widest at posterior border. Glabella broad, width (tr.) 2/3 length (sag.) of glabella anterior to S0, and with rounded crest and flanks and fine tubercles and pits. S1 sloping posteriorly, not curving anteriorly around top of muscle attachment area. L1 inflated. Axial furrows straight, crossing junction of L1 and alae, and weakly converging anteriorly. Preglabellar furrow clearly defined and bowed upwards in anterior view. Occipital furrow deep, narrower (sag.) than posterior border (exsag.) and medially straight in dorsal view. Occipital ring not medially broadened, with fine tubercles and, in lateral view, higher than glabella anterior to S0. Occipital node small and located on swelling on anterior slope of occipital ring. Alae anterolaterally directed and small (tr.), 33% of length (sag.) of glabella anterior to S0 and moderately wide (tr.), being 0.83 of length (exsag.) at junction with axial furrow. Alar furrow deep and with alar depression. Posterior border moderately short (tr.), 35% of width (tr.) of occipital ring. Preglabellar field narrow (sag.), ≈ 13% of width (tr.).

Genal area narrow (tr.), width ≈50% of length (exsag.), and with fine tubercles and pits. Eye lobes large (exsag.), over 35% of width (tr.) of glabella at S0, strongly inflated and located at internal margin of fringe. Each lobe with 3 eye lenses, anterior and posterior oval in shape and of equal size and the third, much smaller, subcircular lens located high up between the two larger lenses. Eye ridge not well defined, genal ridge reaching posterolaterally to prolongation. Inner margin of fringe convex across anterior of genal area and marked by bigger perforations across anterior boss. Anterior boss barely inflated and reaching down to weak girder kink. Genal roll sloping anteriorly at ≈ 450, laterally at ≈ 550. In lateral view, internal fringe strongly narrowing posterolaterally (by ≈35%). Perforations on genal roll smaller than on brim and all approximately same size, except for row of larger perforations next to girder. Caeca present on genal roll.

Brim concave, barely sloping and with width (sag.) 29% of cephalic length (sag.). Brim perforations moderately fine, with standardised diameter of ≈ 145 μm and larger perforations around distal and proximal edges. Caeca reaching onto brim, and brim width ratio ≈0.87. External rim stout (width (sag.)> 10% of brim width (sag.)), and without sculpture on dorsal surface. Marginal band near vertical, concave and with ridges around top and bottom and scattered tubercles in between. Prolongation length (exsag.) 80% of cephalic length (sag.). Internal and external rims curving adaxially, and profile of internal rim is concave in lateral view. Genal spine short (exsag.), following curve of external rim. Tubercles on dorsal surface of internal rim and row of large perforations below.

Remarks. Maghroharpes forteyi has an alar depression but otherwise complies with all the diagnostic characters of its genus shown in Table 5b. Maghroharpes forteyi differs from its sister species M. rouvillei in having: a cephalon that is widest at anterior edge of alae not at the eye lobes; a glabella which is longer, narrower and pitted; a furrow at S1 which does not curve around the top of the muscle attachment area; narrower (exsag.) alae, which do not reach as far across the genal area and are not as inflated as those of M. rouvillei ; an alar depression (not present on M. rouvillei ); eye lobes that are more inflated and larger (exsag.) in relation to width (tr.) of glabella anterior to S0; a genal roll that slopes laterally more gently, at around 550 as opposed to 620 in M. rouvillei ; a wider (sag.)girder with a much more pronounced girder kink; a brim that is concave, rather than having a straight profile, and slopes at around 50 rather than at over 300, with a brim width ratio of around 0.87, compared to 0.61 in M. rouvillei .

Only photographs of partial cephala o f M. rouvillei were available for comparison. M. forteyi is also similar to M. azmamarensis and the holotypes of the two species were found in the same small coral colony. Maghroharpes forteyi differs from M. azmamarensis in having: a much narrower and more vaulted glabella; axial furrows which are straight, converging weakly anteriorly, whereas the axial furrows of M. azmamarensis are convex and more strongly convergent; a narrower preglabellar field; the occipital ring higher than the glabella anterior to S0, rather than being the same height; its alae anterolaterally not laterally directed; more inflated eye lobes; a much narrower genal area, with tubercles and more pronounced perforations; caeca that just reach onto the brim of M. forteyi and not right across it as they do on the brim of M. azmamarensis ; a brim width ratio of 0.87, 10% higher than that of M. azmamarensis ; and the external rim without granulation on its dorsal surface.

Specimen NHMUK It 29284 of M. cf. forteyi ( Pl. 31 F–K ) is very similar but differs in having shorter (exsag.) prolongations, and alae that are slightly wider (tr.) and laterally directed.

Genus Pinnuloharpes n. gen.

Type species. P. segaouii n. sp.

El Otfal formation, Eifelian, from Tarhroat, the Anti-Atlas, Morocco

Diagnosis. Cephalon ovoid, glabella joined to anterior boss, L1 not inflated, occipital furrow shallow and occipital ring not medially broadened. Alar furrows very shallow or effaced; eye lobes set away from inner margin of fringe and with two lenses each, anterior being largest. Course of inner margin of fringe across anterior of genal area concave. Marginal band profile straight and internal rim meeting external rim before joining at end of prolongation. Genal spines long.

Etymology. From the Latin word “pinnula”, a little wing, feather or fin, referring to the small alae of the genus.

Discussion. The genus is closely related to Stoloharpes n. gen. and is comprised of two sister groups and two separate species. One group comes from Eifelian horizons close to Jorf ( Figure 3 Map 6) and neighbouring Timerzite ( Figure 5 Map 10) and the other has one species from the Eifelian of Jorf, the rest coming from the upper Emsian horizons of Hamar Laghdad and Ksar Lbour ( Figure 5 Map 11 and Figure 3 Map 3 respectively).

Species of Pinnuloharpes differ from species of Stoloharpes in having an ovoid rather than pyriform cephalon; a broader (tr.) genicranium that is widest at the posterior border rather than anterior to alae; an occipital furrow which is straight in dorsal view and not medially bowed posteriorly; an inner fringe margin which is concave across the anterior of genal areas and not straight or convex; a genal roll that slopes more steeply anteriorly; a brim that is not convex; a marginal band that is near vertical and does not slope down under the cephalon; and, in lateral view, an external rim that meets internal rim before joining at the end of the prolongation. In the case of Stoloharpes species, the two rims meet and join at the end of the prolongation.

All species included in the study are shown in Figs 9 , 10e. P . fornicates ( Novak, 1890) and P. pygmeaus Lütke, 1965 , which not in the study, are assigned pro tem from Harpes to Pinnuloharpes . The range of Pinnuloharpes is Upper Emsian to upper Eifelian.

Figures

FIGURE 3. Souss–Massa, Tiinghir, West and North Ma’der regions

FIGURE 5. East Ma’der, Tafilalt and Taouz

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 29. A–D Maghroharpes forteyi n. sp., from top of Pragian, Ihandar Formation, El Atchane Jbel Oufatene, dorsal exoskeleton of cephalon, holotype, NHMUK It 29288 (Fig. 2B, Map 8, site 16). A, dorsal B, anterior and C, lateral view. D, dorsal view of brim perforations. E–J,O Maghroharpes azmamarensis n. sp., from top of Pragian, Ihandar Formation, Oued el Atchane Jbel Oufatene, dorsal exoskeleton of cephalon, holotype, NHMUK It 29281 (Fig. 2B, Map 8, site 18). E, dorsal, F, anterior and G, lateral view. H, dorsal and I, lateral view of eye lobe, respectively. J, dorsal view of brim perforations. O, from type locality partial dorsal exoskeleton of lower Lamella, paratype NHMUK It 29283 (Fig. 2B, Map 8, site 19)). K–N Maghroharpes forteyi, from top of Pragian, Ihandar Formation, bou Lachrhal, dorsal exoskeleton of partial cephalon only, paratype, NHMUK It 29289 (Fig. 2B, Map 9, Site 7). K, dorsal, L, anterior and M, lateral view. N, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 31. A–E Maghroharpes aff. ihmadii, dorsal exoskeleton of partial cephalon, NHMUK It 29305, from an upper Pragian horizon, Ihandar Formation, bou Lachrhal (Fig. 2B, Map 9, site 4). A, dorsal, B, lateral and C, anterior view. D, lateral view of eye lobe and E, dorsal view of brim perforations. F–K Maghroharpes cf. forteyi, dorsal exoskeleton of partial cephalon, NHMUK It 29284, from top of the Pragian, Ihandar Formation, Oued el Atchane, Jbel Oufatene (Fig. 2B, Map 8, site 20). F, dorsal, G, anterior and H, lateral view. I, lateral view of eye lobe, J, dorsal view of brim perforations and K, pits on axial node. L–N Maghroharpes cf. zguidensis, dorsal exoskeleton of cephalon, NHMUK It 29328, from MerzâAkhsai Formation?, Pragian, Douar Laayoune, Tata (Fig. 2B, Map 1, site 1). L, dorsal and M, lateral view. N, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.