A new species of the genus Prosopistoma Latreille, 1833 (Ephemeroptera, Prosopistomatidae) from Morocco Author El Alami, Majida https://orcid.org/0000-0003-2664-646X Laboratoire Ecologie, Systematique, Conservation de la Biodiversite (LESCB), Unite de Recherche Labellisee CNRST N ° 18, Universite Abdelmalek Essaadi, Faculte des Sciences, Departement de Biologie, B. P. 2121 93002, Tetouan, Morocco elalami.majida@gmail.com Author Benlasri, Mokhtar Museum d'Histoire Naturelle de Marrakech, Universite Cadi Ayyad, Faculte des Sciences, Semlalia, B. P. 2390, Marrakech, Morocco Author Sartori, Michel https://orcid.org/0000-0003-3397-3397 Museum of Zoology, Palais de Rumine, Place Riponne 6, CH- 1005, Lausanne, Switzerland & Department of Ecology and Evolution, Lausanne University, CH- 1015, Lausanne, Switzerland Author Vuataz, Laurent https://orcid.org/0000-0001-9193-8683 Museum of Zoology, Palais de Rumine, Place Riponne 6, CH- 1005, Lausanne, Switzerland & Department of Ecology and Evolution, Lausanne University, CH- 1015, Lausanne, Switzerland Author Ghamizi, Mohamed Museum d'Histoire Naturelle de Marrakech, Universite Cadi Ayyad, Faculte des Sciences, Semlalia, B. P. 2390, Marrakech, Morocco text ZooKeys 2022 2022-08-15 1117 203 218 http://dx.doi.org/10.3897/zookeys.1117.83539 journal article http://dx.doi.org/10.3897/zookeys.1117.83539 1313-2970-1117-203 B2596F5CFE214B3EAAECDE33FF394CEC 76BC5EBEBEA65F82903D460EBF22B366 Prosopistoma maroccanum El Alami, Benlasri & Sartori sp. nov. Material examined. Holotype : Morocco • 1 nymph in ethanol; Beni-Mellal Province , Oued Laabid , in Bzou village , 32°6.076'N , 7°2.644'W , 372 m alt., 14 December 2021 , coll. M. Benlasri (MZL GBIFCH01119080) . Paratypes : Morocco • 1 nymph in ethanol, same data as holotype (MZL GBIFCH01119081); 1 nymph on slide, same data as holotype (MZL GBIFCH00608997; 7 nymphs in ethanol, same data as holotype (LESCB); 1 nymph on slide, same data (LESCB); 3 nymphs in ethanol, same sampling site, 08 May 2021 ; 4 nymphs in ethanol, same sampling site, 14 October 2021 , Coll. M. Benlasri (MHNM) • 4 nymphs in ethanol, Beni-Mellal Province , Oued Laabid , in Imdahen village , 32°8.252'N , 7°1.764'W , 364 m alt., 06 March 2016 , coll. H. Hajjani (MZL GBIFCH00980869); 1 nymph on slide, same data (MZL GBIFCH00970951); 5 nymphs in ethanol, same data (LESCB); 5 nymphs in ethanol, same site, 08 May 2021 ; 7 nymphs in ethanol, same site, 14 October 2021 , Coll. M. Benlasri (MHNM) . Description. Nymph (in alcohol). Body length 3-4 mm excluding caudal filaments. Notal shield (carapace) length along median suture 2 mm and total length of body 4.0 mm. Carapace (Fig. 3 ), wider than long, width/length ratio: 1.15-1.25; head width/length ratio:2.5, head width/carapace width ratio: 0.58-0.60; distance between eyes/head width ratio: ca 0.53 for male nymphs and 0.58 for female nymphs. Carapace flange relatively wide (Fig. 3 ). Figure 3. Nymphal dorsal view of Prosopistoma maroccanum sp. nov. Head . Yellowish-brown, with a brownish spot above the median ocellus and between antennae (Fig. 3 ). Compound eyes roughly oval, blackish, slightly larger than oval lateral ocelli in male nymphs (Fig. 4A ). Epicranial suture hardly discernible crossing the middle part of lateral ocelli, and between compound eyes and antennal bases (Fig. 4A ) and progressing to the head's lateral margin. Antennae 7-segmented (including scape and pedicel) in mature nymphs (Fig. 4B ), 6-segmented in younger specimens (Fig. 4C ); segment III shorter than the total length of segment IV-VI or VII (respectively 0.64 x and 0.95 x ), length of segment III/segments IV-V ratio: 1.18-1.21; antennae not extending beyond the head's anterior edge. Figure 4. Prosopistoma maroccanum sp. nov. A head of larva B antennae with 7 segments C antennae with 6 segments. Labrum (Fig. 5A ) narrow, 3.25 x broader than long, anterior margin convex in medial section and straight laterally, anterior margin fringed with fine setae. Figure 5. Prosopistoma maroccanum sp. nov. A labrum (dorsal view) B right mandible (ventral view) C bristles arising from base of inner canine D left maxilla (ventral view) E canine (c) and moveable strong dentisetae (d1, d2, d3) F labium (ventral view) G labial-palp. Left and right mandibles similar (Fig. 5B ). Outer canine distinctly longer and wider than inner canine with three apical teeth, inner one slightly longer than the two others. Outer margin of outer canine with 4-6 micro teeth, inner margin of outer canine with 4 or 5 micro teeth; first distal micro tooth large, conspicuous, more than twice as long and wider than others. Mandible inner canine, one-third shorter than outer canine, rod-shaped, apically bifurcate and forming a pair of elongate and thin pointed teeth with three subapical sharply pointed teeth. 6 or 7 long serrated bristles arising from base of inner canine (Fig. 5C ); two first anterior bristles shorter than remaining, and one long simple bristle in the middle of outer margin of mandible. Maxillae (Fig. 5D, E ) crowned by a rigid canine and three moveable, strong dentisetae of subequal length (Fig. 5E ). A row of 2 or 3 strong serrated bristles appear below the dentisetae and a single finer bristle on proximal part of sclerotized galea (Fig. 5E ). Maxillary palp 3-segmented; segment II long and clearly longer than segment I (1.3-1.5 times) (Fig. 5D ). Labial palps 3-segmented, reaching front margin of labium (Fig. 5F ). Labial palp segment II 0.9 x length of segment I, segment III 0.5 x length of segment II (Fig. 5G ). Thorax . Carapace yellowish brown, with distinct ornamentation (Fig. 6A ) and four irregular brownish markings, two on each side of midline of central region of carapace at approximately 0.20 x length of carapace from posterior margin of head (Fig. 3 ); also, there are markings from the anterior end of the carapace at approximately 60° angle to the midline; carapace flange and distal part of carapace transparent but not apparently translucent; relatively wide. Posteromedial part of carapace distinctly concave (Figs 3 , 6A ). Legs . Fore femora with reticulate pattern on dorsal surface consisting of scale-like structures more accentuated at the anterior and posterior border (Fig. 6B ); dorsal margin of femora with simple and fine setae; ventral margin of fore tibia with 6-8 pectinate setae (Fig. 6C ). All tarsal claws sharp, slender, smooth, and without denticles. Abdomen . Abdominal gills (Fig. 6D-F ). Gill I upper portion lamellate with serrated margin, apically slightly asymmetric and rounded; lower section cleaved in numerous filaments with about 6-8 major branches divided into 17-22 filaments (Fig. 6D ). Gill II with rectangular lamella (ratio width/length ca 1.10); posterior margin and outer lateral margin concave with short, pointed spines; inner lateral margin convex without spines (Fig. 6E ), covering gills III-V appearing with multiple branching filaments, decreasing in number towards gill V (Fig. 6F ); gill III with 6 main stems; gill VI conical in shape, very small and unbranched. Abdominal segments VII-IX apparently angular with straight posterior margins; posterolateral projections nearly symmetric, with straight inner margins and relatively pointed apex (Fig. 6G ). Segment X rectangular, relatively longer than wider. Caudal filaments, retractile, short, plume-like. Figure 6. Prosopistoma maroccanum sp. nov. A posteromedial part of carapace B scale-like pattern on femur (ventral view) C ventral margin of fore tibia D gill I E gill II F gill III G abdominal segments VII-IX. Imago . Not known. Morphological remark. As already mentioned by Gillies (1954) and Peters (1967) , and well documented by Dalkiran (2009) and Schletterer et al. (2016) , the number of segments forming the antenna is subject to some variation. In P. maroccanum , mature nymphs possess 7 segments, while younger ones have only 6 segments. Therefore, the ratio length of segment III vs length of the remaining segments is to be use cautiously and may have a taxonomic value only when applying to mature nymphs with 7 segments, since this ratio is around 0.95 (subequal) for 6-segmented antennae vs 0.65 (much shorter) for 7-segmented antennae. Diagnosis. The nymph of P. maroccanum sp. nov. appears to be more closely similar to P. pennigerum than to P. alaini from Algeria (Table 2 ). Table 2. Morphological discriminant characters between the seven Prosopistoma species from the Western Palearctic.

Characters	P. maroccanum	P. pennigerum	P. alaini	P. oronti	P. orhanelicum	P. turcica	P. helenae
Antennal segments in mature nymphs ( N )	7	6	7	5	7	6	6
Antenna reaching/not reaching anterior margin of head	not reaching	reaching	not reaching	not reaching	not reaching	not reaching	reaching
Setae on the right mandible ( N )	6-7	7-8	8-9	7-9	7	5	5
Subapical teeth on outer margin of outer canine ( N )	6-7	6-8	5	6-9	7-8	4-5	4-6
Pectinate setae on inner margin of fore tibia (N)	6-8	10-11	10-14	6-7	9-10	7	6-7
Filaments on gill I (N)	17-22	24-28	21-23	12-14	>40	20-22	15-17
Lateral outer margin of gill II	concave	concave	concave	concave	concave	straight	straight
Shape of distal medial margin of carapace	distinctly concave	shallowly concave	straight	distinctly concave	convex	distinctly concave	distinctly concave
Ornamentation of the carapace	distinct	distinct	indistinct	distinct	indistinct	distinct	indistinct
Ratio carapace width / length	1.15-1.25	0.8-0.9	1.1	1.1-1.2	1.1-1.4	1.13	1.2-1.3
Distribution	Morocco	Europe	Algeria	Levant	Turkey	Turkey	Iraq

Indeed, it differs from the latter in several aspects, mainly the distinct ornamentation of the carapace, the lower number of setae on the right mandible (6 vs 8-9), the more numerous subapical teeth on outer margin of the outer canine (6-7 vs 5), the number of maxillary dentisetae (3 vs 4), the distinctly concave distal medial margin of carapace (almost straight in P. alaini ), and above all by the fewer pectinate setae on the inner margin of fore tibia (7-8 vs 10-14). This last character also separates P. maroccanum from P. pennigerum (10-11), as well as the number of antennal segments in mature nymphs (7 vs 6), the antenna not reaching the anterior margin of the head (reaching in P. pennigerum ), and the ratio width/length of the carapace higher in P. maroccanum (1.25 vs 0.9). Furthermore, gill I has the apical tip of the dorsal lamina shorter in P. maroccanum than in P. pennigerum . In addition, the ventral filamentous part possesses a number of main stems which overlap (7-8 vs 8-10) but with a greater number of filaments in P. pennigerum (24-28 vs 17-22). Prosopistoma maroccanum differs from P. oronti mainly by the number of antennal segments (5 in P. oronti ) and the length of segment II of the antenna shorter compared to the following segments (longer in P. oronti ). It differs from P. turcica mainly by the number of antennal segments (6) and the setation of the right mandible, from P. orhanelicum by the fewer subapical teeth on inner margin of outer canine (4-5 vs 6-7), the shape of the distal medial margin of the carapace (convex in P. orhanelicum ), and the fewer pectinate setae on the inner margin of fore tibiae (9-10 in P. orhanelicum ). From P. helenae , P. maroccanum differs in having abdominal segments VII-IX angular (rounded in P. helenae ) and in the number of antennal segments and length (antenna 6-segmented and reaching the anterior margin of the head in P. helenae ). Ecology. Prosopistoma maroccanum sp. nov. was collected at two sites in the Laabid River, 117 km from Marrakech. The greatest density, 10 specimens, was recorded in December 2021 at site 2 (Imdahen locality; Fig. 7B ). At this site, the bottom structure was composed of 70% pebbles, 20% gravel, and 10% silt. During the sampling campaign, water temperatures were 22.4-23.7 °C, dissolved oxygen 6.57-8.26 mg/l, pH 8.05-8.17, and conductivity 977-999 µS /cm. The channel, about 6 m wide and about 20 cm deep, had a moderate current velocity and turbid water. There was almost no riparian vegetation along the stream banks and no submerged macrophyte cover. Prosopistoma species are very sensitive to organic pollution and habitat degradation ( Barber-James 2010a ). However, there are small villages near the two sampled locations (Fig. 7A, B ) which probably increased the turbidity and organic pollution in the water. These impacts probably explain the low density, or the absence of this species, at other sampled sites. The ecological aspects such as microhabitat, nutrition, life history, and phenology of P. maroccanum sp. nov. should be further investigated. Figure 7. Sampling sites of Prosopistoma maroccanum sp. nov. A site 1 (Bzou locality) B site 2 (Imdahen locality).