Lioharpes saredra, Johnson, 2024

Johnson, Robert G., 2024, Devonian Harpetidae from the central and eastern Anti-Atlas, Morocco, Zootaxa 5450 (1), pp. 1-185 : 59-61

Lioharpes saredra n. sp.

Plates 14A–N , 15A–N

Diagnosis. Cephalon widest at eye lobes. Muscle attachment scars on glabella visible at S2, S3 and S4 barely reaching out of axial furrow. Alae well-defined and with alar furrow and ridge. Eye lobes close to inner margin of fringe; eye ridge and genal ridge present and inner margin of fringe concave across the anterior of genal areas. Genal roll sloping anteriorly moderately steeply (just under 600) down to narrow girder with prominent oval recesses beneath, formed by caecal ridges radiating down from girder. Brim wide (sag.) (between 25% and 38% of cephalic length (sag.)), external rim narrow (less than 10% of width (sag.) of brim). In lateral view, internal rim is straight and slopes down posteriorly at a shallow angle.

Etymology. Named after type locality, Jbel Saredrar.

Material and occurrence. Holotype: NHMUK It 29274, Pl. 14A–I , from “ Odontochile Couche ”, upper Pragian— lower Emsian , Boutiskaouine Formation?, Jbel Saredrar ( Fig. 2B, Map 5, site 2), a dorsal exoskeleton, thorax disarticulated and enrolled . Paratype: NHMUK It 29275, Pl. 14J–N , from type locality and horizon (site 1), a dorsal exoskeleton with pygidium enrolled . Paratype: NHMUK It 29276, Pl. 15A–C , from “ Odontochile Couche ” Taganant, Boutiskaouine Formation, Emsian, Jbel Oufatene ( Fig. 2B, Map 8, site 7), dorsal exoskeleton of a partial cephalon only . Paratype: NHMUK It 29278, Pl. 15D–J , from the “ Destombina” Horizon, Amerboh Group (Upper), base of upper Emsian , el Khraoua, Jbel Shebras ( Fig. 2B, Map 12, site 1), disarticulated dorsal exoskeleton . Paratype: NHMUK It 29277, Pl. 15K–N , from a coral reef at the Emsian / Pragian boundary at the base of the northern slope of Jbel bou Lachrhal ( Fig. 2B, Map 9, site 1), dorsal exoskeleton of a cephalon only .

Description. Cephalon widest posterior to eye lobes, close to mid-point between eye lobes and alae; genicranium widest at posterior border, width (tr.) nearly 135% of length (sag.). Glabella width (tr.) anterior to S0 ≈ 67% of length (sag.), flanks convex and crest rounded with tubercles and very fine pitting. S1 sloping posterolaterally, becoming effaced before curving anteriorly near crest; S2, S3, S4 depressions barely reaching out of axial furrow and L1 inflated. Axial furrows convex, converging anteriorly at over 150 and not crossing junction between L1 and alae. Preglabellar furrow distinct and straight (tr.) in anterior view. Occipital furrow deep medially, straight (tr.) and about same width (sag.) as posterior border (exsag.). Occipital ring has tubercles on dorsal surface and its width (sag.) is about same as occipital furrow and, in lateral view, its height same or little higher than glabella anterior to S0. Occipital node small, barely inflated and located on anterior slope of occipital ring. Alae laterally directed, small (tr.) and moderately wide (exsag.). Alar furrow deep, well-defined, interalar ridge and furrow and alar depression present. Preglabellar genal area narrow, with width (sag.) 14% of width (tr).

Genal area moderately broad with width (tr.) ≈55% of length (sag.) and dorsal surface with faint caeca, pits and tubercles. Caeca more evident on ventral surface of genal areas, as evidenced by impressions on matrix under cuticle ( Pl. 15G ). Eye lobes large (exsag.), oval, with coarse tubercles on dorsal surface and located close to internal margin of fringe. Each lobe with two recumbent oval eye lenses of roughly equal size. Eye ridge straight (tr.), well defined. Anterior boss reaching down to girder kink; girder very narrow. (sag. and exsag.). Genal roll sloping moderately steeply anteriorly at just under 600, steeply laterally at just under 700, and with caeca and row of large perforations immediately above girder and across anterior boss at inner margin of fringe; other perforations smaller than on brim.

Brim wide, width (sag.) in dorsal view ≈37% of cephalic length (sag.), concave (sag.), straight laterally and sloping moderately at ≈ 170. Brim width ratio around 0.70. Brim perforations moderately large with diameter over 190 μm and row of larger perforations around distal and proximal edges; caeca reaching onto brim. External rim fine, under 10% (sag.) of brim width (sag.) and external band near vertical with ridge top and bottom and scattered tubercles in between. Brim steepens quickly to near vertical on prolongations. Prolongations moderately long (exsag.), just under 90% of cephalic length (sag.) and in dorsal view, internal and external rims curving adaxially posteriorly. In lateral view, profile of internal rim concave and external rim curving smoothly upwards to meet internal rim. Extension of girder meeting internal rim nearly halfway down prolongation. Row of large perforations below internal rim. Genal spine short and carried on lower lamella.

Thorax with 20 thoracic segments with pleurae widening (tr.) more than reduction in width (tr.) of axis until third segment. Pleural furrows narrow, shallow but well defined. Outer portion of pleurae straight with rounded ends and not offset against inner portion. Pygidium has 3 weakly vaulted axial rings with first two pleural ribs reaching edge of pygidium, and interpleural furrows defining posterior rib petering out on pleural field. Terminal piece gently curved with slight medial indentation ( Pl. 15I ).

Hypostome not known.

Remarks. Lioharpes saredra lacks three of the diagnostic characters of the genus shown 5a: it has two eye lenses per eye lobe rather than three, the course of the inner margin of the fringe across the anterior of the genal areas is concave and not straight, and the girder is particularly narrow.

Paratype NHMUK It 29278 has tubercles on the dorsal surface of the rim ( Pl. 15J ) not present on the holotype or other paratypes, which are earlier, from lower Emsian horizons. The pygidium of NHMUK It 29278, the only pygidium figured here, may also have small insignificant differences with pygidia from the lower Emsian .

Lioharpes saredra is most similar to L. ammari but has a number of differences, the most important of which are that it has a narrower glabella, which is less tapered anteriorly, has convex flanks and a rounded crest with fine scattered granules, rather than the carinate crest with coarse tubercles found on the glabella of L. ammari . Also, the glabella has shallow muscle insertion pits at S2, S3 and S4, which are not visible on the glabella of L. ammari ; The occipital ring in lateral view is lower than that of L. ammari , being close to the same height of glabella anterior to S0; eye lobes are less tall and located a little further from internal margin of fringe and eye ridges that are not present on L. ammari . Also not present on L. ammari are the pitting, fine caeca and scattered granulation present on the dorsal surface of genal areas ( Pl. 14E ) of L. saredra . The course of the fringe inner margin across the anterior of the genal of area of L. saredra is concave rather than straight; it has a more inflated anterior boss and a well-defined girder kink; its genal roll is much steeper with caeca and perforations that do not decrease away from the girder as in the case of L.ammari ; its external rim is finer, its width (sag.) being ≈8% of width (sag.) of brim, compared to ≈11% in the case of L. ammari . On the thorax, the axis is broader anteriorly and tapers more strongly posteriorly in L. saredra ; pleural furrows are broader and pleurae do not shorten (tr.) posteriorly until the 8 th segment, whereas those of L. ammari start to shorten (tr.) at the 6 th segment.

Genus Fritchaspis Vaněk , (emend.) 1963

Type species. Harpes montagnei Hawle & Corda, 1847 from Acanthopyge Limestones, Chotec formation, (Eifelian), Koněprusy area, Czech Republic (exact location unknown).

Diagnosis. Genicranium narrow, length (sag.) between 75% and 85% of width (tr.). Glabella inset and preglabellar furrow bowed upwards in anterior view. No tubercles on occipital ring. Posterior border moderately wide (tr.), between 41% and 50% of width (tr.) of occipital ring. Alar depression present and course of inner margin of fringe across anterior of genal area straight. Genal roll sloping moderately anteriorly (sag.) at between 420 and 500 to horizontal. Brim wide (sag.)>35% of cephalic length (sag.) and steepening to less than vertical on prolongations. Brim width ratio between 0.86 and 0.94. Spaces between brim perforations inflated. Prolongations moderately short (exsag.), between 76% and 85% of cephalic length (sag.).

Discussion. Fritchaspis was established by Vanek in 1963, reduced to a subgenus of Lioharpes by Přibyl & Vaněk in 1986 and in 2002 Ebach & McNamara (2002) made it a junior subjective synonym of Lioharpes , on the basis that the then diagnosis of Fritchaspis was synonymous with that of Whittington’s Lioharpes . Here, the author re-establishes Fritchaspis as a genus on the basis of revised diagnoses for both Fritchaspis and Lioharpes . Fritchaspis perneri , and F. wendti are assigned from Lioharpes and Fritchaspis sp. 2 ( Feist, 1977) from Harpes . Fritchaspis differs from Lioharpes in having: a glabella that is less tapered anteriorly; the dorsal surface of its brim between the brim perforation is inflated, whereas Lioharpes species have a caeca network across the brim which is light to moderate; a girder that extends onto the prolongation to meet the internal rim one third of the way down the prolongation, rather than halfway down as in the case of Lioharpes . Fritchaspis is shown ( Figs 9 and 10d ) to be more closely related to Eskoharpes and a comparison is given in the systematics of Eskoharpes below.

The two representative species from Czech Republic, Fritchaspis montagnei ( Pl. 57A–F ) and Fritchaspis perneri ( Pl. 56G–K ), have the additional differences from Lioharpes of having a small axial tubercle on the anterior quarter of the glabella. The glabella is otherwise free of tubercles, as are the genal areas. Also, they have a broader (tr.) posterior border. These two species are the only ones which were included in the former subgenus Lioharpes (Fritchaspis) . All species of the genus have been included in the study and are shown in Fig. 10d . The range of the genus is from Emsian to Eifelian.

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 14. A–N Lioharpes saredra n. sp., from “Odontochile Couche”, Boutiskaouine Formation, Emsian, Jbel Saredrar (Fig. 2B, Map 5). A–I dorsal exoskeleton, thorax disarticulated and enrolled, holotype, NHMUK It 29274 (site 1).A, dorsal, B, anterior, C, lateral and H, posterior view. D, posteroventral view of prolongation, E, dorsal surface of genal area. F, dorsal view of brim perforation, G, lateral view of eye lobe, I, dorsal lateral view of pleurae. J–N dorsal exoskeleton with pygidium enrolled, paratype, NHMUK It 29275 (site 2). J, dorsal, K, anterior and L, lateral view. M, lateral view of glabella (uncoated) and N, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 15. A-N Lioharpes saredra n. sp. A–C partial dorsal exoskeleton of cephalon from “Odontochile Couche” Boutiskaouine Formation, Emsian, Jbel Oufatene (Fig. 2B, Map 8, site 7), paratype, NHMUK it 29276. A, dorsal and B, lateral view. C, dorsal view of brim perforations. D–J disarticulated dorsal exoskeleton, from the Destombina Horizon, Tazoulait Formation, upper Emsian,Jbel Shebras (Fig. 2B, Map 12, site 1), paratype, NHMUK It 29278. D, dorsal, E, lateral and F, anterior view. Dorsal view of: G, genal area showing internal mould, H, brim perforations, I, pygidium and J external rim. K–N dorsal exoskeleton of cephalon only, from coral at the top of the Pragian, Ihandar Formation, bou Lachrhal (Fig. 2B, Map 9, site 1), paratype, NHMUK It 29277. K, dorsal, L, anterior and M, lateral view. N, dorsal view of brim perforations. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 56. A–F Bohemoharpes vittatus (Barrande 1852); type horizon and locality with Prionopeltis archiaci, Kopanina Formation (Ludlow) Praha-Lochkov, dorsal exoskeletons of 2 partial cephala, Natural History Museum Prague Nos L 12549 and L 12565. A–C, L 12549, A dorsal view, B lateral view and C anterior view. D–F, No. L 12549, D dorsal view of cephalon, E brim perforations and F genal area including eye lobe and genal ridge. G–K Fritchaspis perneri, Prantl & Přibyl,1954 type horizon and locality Třebotov Limestones, Praha-Holyně Czech Republic, three dorsal exoskeletons of three partial cephala, Natural History Museum Prague No. L6140 and Czech Geological Survey Nos JV15912 and JV15897. G–I, No. L6140 holotype, G dorsal view of partial cephalon, H anterior of glabella with axial tubercle and I brim perforations. J, No. JV15912 dorsal view of genicranium and K, No. JV 15897 dorsal view of partial cephalon. Scale bars shown represent 1 cm unless otherwise indicated.

PLATE 57.A–F Fritchaspis montagnei (Hawle and Corda, 1847) type horizon and locality Acanthopyge Limestones (Eifelian), Koněprusy area, Czech Republic, five dorsal exoskeleton of partial cephala, Museum of Natural History, Prague, syntype Nos L 2996 (one of four syntypes) and L 2990. A–C, L 2996, a partial cephalon, A dorsal view, B anterior view and C lateral view. L 2990, D–F a plate with four partial cephala, D dorsal view, E lateral view of largest cephalon and F dorsal vie of brim perforations. G–J Declivoharpes praecedens by (Prantl and Přibyl 1954,) type horizon and locality Radotín Limestones (Lochkovian), praharadotín (Černá rokle gorge) dorsal exoskeleton of partial cephalon, Museum of Natural History, Prague holotype No. L19103. G dorsal view, H anterior view, I lateral view and J dorsal view of brim perforations. This specimen was illustrated by Prantl and Přibyl (1954, pl. 8 fig.2). Scale bars shown represent 1 cm unless otherwise indicated.