Prosopistoma maroccanum El Alami, Benlasri & Sartori, 2022

El Alami, Majida, Benlasri, Mokhtar, Sartori, Michel, Vuataz, Laurent & Ghamizi, Mohamed, 2022, A new species of the genus Prosopistoma Latreille, 1833 (Ephemeroptera, Prosopistomatidae) from Morocco, ZooKeys 1117, pp. 203-218 : 203

publication ID	https://dx.doi.org/10.3897/zookeys.1117.83539
publication LSID	lsid:zoobank.org:pub:B2596F5C-FE21-4B3E-AAEC-DE33FF394CEC
persistent identifier	https://treatment.plazi.org/id/9C03C91D-8E32-47C7-9FD1-DE01A7093072
taxon LSID	lsid:zoobank.org:act:9C03C91D-8E32-47C7-9FD1-DE01A7093072
treatment provided by	ZooKeys by Pensoft
scientific name	Prosopistoma maroccanum El Alami, Benlasri & Sartori
status	sp. nov.

Treatment

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) GoogleMaps . 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) GoogleMaps .

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 View Figure 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 View Figure 3 ).

Head. Yellowish-brown, with a brownish spot above the median ocellus and between antennae (Fig. 3 View Figure 3 ). Compound eyes roughly oval, blackish, slightly larger than oval lateral ocelli in male nymphs (Fig. 4A View Figure 4 ). Epicranial suture hardly discernible crossing the middle part of lateral ocelli, and between compound eyes and antennal bases (Fig. 4A View Figure 4 ) and progressing to the head’s lateral margin. Antennae 7-segmented (including scape and pedicel) in mature nymphs (Fig. 4B View Figure 4 ), 6-segmented in younger specimens (Fig. 4C View Figure 4 ); segment III shorter than the total length of segment IV-VI or VII (respectively 0.64 × and 0.95 ×), length of segment III/segments IV-V ratio: 1.18-1.21; antennae not extending beyond the head’s anterior edge.

Labrum (Fig. 5A View Figure 5 ) narrow, 3.25 × broader than long, anterior margin convex in medial section and straight laterally, anterior margin fringed with fine setae.

Left and right mandibles similar (Fig. 5B View Figure 5 ). 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 View Figure 5 ); two first anterior bristles shorter than remaining, and one long simple bristle in the middle of outer margin of mandible.

Maxillae (Fig. 5D, E View Figure 5 ) crowned by a rigid canine and three moveable, strong dentisetae of subequal length (Fig. 5E View Figure 5 ). 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 View Figure 5 ). Maxillary palp 3-segmented; segment II long and clearly longer than segment I (1.3-1.5 times) (Fig. 5D View Figure 5 ).

Labial palps 3-segmented, reaching front margin of labium (Fig. 5F View Figure 5 ). Labial palp segment II 0.9 × length of segment I, segment III 0.5 × length of segment II (Fig. 5G View Figure 5 ).

Thorax. Carapace yellowish brown, with distinct ornamentation (Fig. 6A View Figure 6 ) and four irregular brownish markings, two on each side of midline of central region of carapace at approximately 0.20 × length of carapace from posterior margin of head (Fig. 3 View Figure 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 View Figure 3 , 6A View Figure 6 ).

Legs. Fore femora with reticulate pattern on dorsal surface consisting of scale-like structures more accentuated at the anterior and posterior border (Fig. 6B View Figure 6 ); dorsal margin of femora with simple and fine setae; ventral margin of fore tibia with 6-8 pectinate setae (Fig. 6C View Figure 6 ). All tarsal claws sharp, slender, smooth, and without denticles.

Abdomen. Abdominal gills (Fig. 6D-F View Figure 6 ). 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 View Figure 6 ). 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 View Figure 6 ), covering gills III-V appearing with multiple branching filaments, decreasing in number towards gill V (Fig. 6F View Figure 6 ); 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 View Figure 6 ). Segment X rectangular, relatively longer than wider. Caudal filaments, retractile, short, plume-like.

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 View Table 2 ).

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 View Figure 7 ). 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 View Figure 7 ) 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.