Ephemeroptera: Prosopistomatidae) from Iraq and Algeria

Zootaxa 4018 (1): 109–123 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Article ZOOTAXA Copyright © 2015 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.4018.1.6 http://zoobank.org/urn:lsid:zoobank.org:pub:35F31A6B-6003-4F95-A65A-C04BD6C86A95 Two new species of the genus Prosopistoma (Ephemeroptera: Prosopistomatidae) from Iraq and Algeria

JINDŘIŠKA BOJKOVÁ1,2,4 & TOMÁŠ SOLDÁN3 1Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic. E-mail: [email protected] 2Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005 České Budějovice, Czech Republic 3Institute of Entomology, Biology Centre CAS, Branišovská 31, CZ-37005 České Budějovice, Czech Republic. E-mail: [email protected] 4Corresponding author

Abstract

In addition to the three so far known species of Prosopistoma Latreille, 1833 from West Palaearctic region, P. pennigerum (Müller, 1785), P. oronti Alouf, 1977 and P. orhanelicum Dalkıran, 2009, two new species are described based on larvae. Prosopistoma helenae sp. n. has been found in Iraq (Tigris River in Mosul) and Prosopistoma alaini sp. n. in Algeria (Oued Isser, Sidi Abdelli). Critical distinguishing characters of all West-Palaearctic species of Prosopistoma are discussed in detail.

Key words: Prosopistoma, new species, Maghreb, North Africa, Middle East

Introduction

The monotypic family Prosopistomatidae is a small and highly derived group of mayflies known from the Palaearctic, Afrotropical, Oriental and Australasian regions (Barber-James et al. 2008), with the highest diversity in the Oriental and Afrotropic regions Gillies 1954,;Peters 1967; Soldán & Braasch 1987; Barber-James et al. 2008; Barber-James 2009; Shi & Tong 2013). Three species have been known from the Palaearctic region up to now. Prosopistoma pennigerum (Müller, 1785) was originally widespread in Europe (except northernmost Europe and British Islands), reaching to west Russia, Turkey and Georgia in the east (e.g. Schletterer & Füreder 2009). However, its present occurrence is strongly limited due to pollution and habitat degradation (Schletterer & Füreder 2009). Prosopistoma oronti Alouf, 1977 was recorded from Lebanon (Alouf 1977; Thomas et al. 1988), Syria and Israel (Koch 1988) and Prosopistoma orhanelicum Dalkıran, 2009 was recently described from north western Turkey (Dalkıran 2009). This study is focused on a revision of North African and Middle East material present in the collection of V. Landa and T. Soldán in Biology Centre, Czech Academy of Sciences in České Budějovice. Specimens collected in Algeria have been originally considered to belong to P. pennigerum by T. Soldán (Gagneur & Thomas 1988; Thomas 1988). However, Barber-James (2009) considered records mentioned by these authors as a new species and discussed possible relationships to the material collected in the Atlas Mountains in Morocco (Touabay et al. 2002). She pointed out the lack of available material to describe a new species. Specimens collected in Iraq have been originally assigned to P. phoenicium, which is a synonym of P. oronti, by T. Soldán (Bauernfeind & Soldán 2012). The aim of this study is to describe two new species based on the above-mentioned material and compare them with other Palaearctic species of the genus. We also briefly described P. pennigerum based on the material from Portugal, France and Hungary using the same characters as in the description of the new species to make exact comparison.

Accepted by M. Sartori: 6 Aug. 2015; published: 14 Sept. 2015 109 Description

Prosopistoma helenae sp. n.

Larva. Notal shield (carapace) length along median suture 2.5 mm and total length of body 4.0 mm. Carapace wider than long, width 1.2–1.3 x length; head width 3 x length and 0.6 times carapace width. Carapace flange relatively wide (Figs 1A, 2). Head: Head yellowish-brown unicoloured, antennae lighter. Compound eyes oval, blackish, slightly smaller than oval lateral ocelli (Figs 1A, 2). Epicranial suture weakly visible, passing through middle part of lateral ocelli, and between compound eyes and antennal bases (Fig. 3A). Antennae 6-segmented, third segment shorter (0.8 x times) than total length of segments IV–VI; antennae reaching anterior margin of head (Fig. 3A). Mouthparts: Fore margin of labrum convex in medial part and straight laterally, with short fringe of thin setae (Fig. 3A). Dorsal surface of labrum densely covered with articulated tiny hair-like setae, without any apparent microstructures.

FIGURE 1. A—Prosopistoma helenae sp. n. (paratype), B—Prosopistoma alaini sp. n. (paratype, mature larva), C— Prosopistoma pennigerum (mature larva), D—Prosopistoma oronti (immature larva), E—Prosopistoma oronti (carapace and abdomen of mature larva), F—Prosopistoma helenae sp. n. (detail of abdomen), G—Prosopistoma alaini sp. n. (detail of abdomen).

Outer canine of mandible with three apical teeth of approximately same length, inner one slightly longer (Fig. 3B). Outer margin of outer canine with 4–6 teeth, inner margin of outer canine with 3–5 teeth; first distal tooth large, conspicuous, more than twice as long and wider than others. Inner canine of mandible shorter by one third than outer one, rod-like, apically bifurcate, with a pair of elongate and narrow pointed teeth, with three subapical sharply pointed teeth (first tooth markedly longer than following teeth). Five serrated long setae arising from base of inner canine, first anterior seta shorter than remaining setae, and one long simple seta in the middle of outer margin of mandible. A field of setae and setal sockets medially to basally on mandible. Maxilla with four dentisetae, three long and mildly serrated setae near base of dentisetae and one simple seta near base of galeolacinia (Fig. 3C). Maxillary palp 3-segmented, segment II long, distinctly longer than segment I (1.7–1.8 times). Labium typical of Prosopistomatidae (Fig. 3D). Labial palps 3-segmented, reaching front margin of labium. Labial palp segment II 0.8 times length of segment I, segment III 0.5 times length of segment II. Thorax: Carapace yellowish-brown, without any markings, carapace flange and distal part of carapace transparent (Fig. 1A). Posteromedial part of carapace distinctly concave (Fig. 6A). Fore femora and coxa with reticulate pattern on dorsal surface consisting of scale-like hexagonal or pentagonal structures; dorsal margin of femora with over 20 fine and simple setae (Fig. 4). Ventral margin of fore tibiae with six or seven large and pointed spines with pectinate inner margins (with about 6–7 acute teeth) and one long rounded seta on distal margin of tibiae; dorsal margin of tibiae with two simple setae submarginally; dorsal surface of tibia with several double (V-shaped) setae; ventral surface of tibia with 4–5 stout pointed setae (Fig. 4). Fore tarsus with several long pointed setae along both dorsal and ventral margins and on dorsal surface.

NEW PALAEARCTIC PROSOPISTOMA Zootaxa 4018 (1) © 2015 Magnolia Press · 111 FIGURE 3. Prosopistoma helenae sp. n., A—head of larva as seen flattened under a compound microscope preparation, B— right mandible, C—right maxilla, D—labium, left ventral view, right dorsal view.

112 · Zootaxa 4018 (1) © 2015 Magnolia Press BOJKOVÁ & SOLDÁN FIGURE 4. Prosopistoma helenae sp. n., foreleg of larva with enlargement of scales covering the surface of coxa and femur and pectinate setae on tibia.

Lamella of gill I apically not extended, but slightly asymmetric and rounded; fully-grown larva with about 8–9 major filaments branching of gill I (Fig. 5A). Gill II rectangular (ratio width/length 0.75), posterior margin evidently concave, outer lateral margin straight, inner lateral margin distinctly convex (Fig. 5A). Abdomen: Abdominal segments VII–IX apparently round or even semi-circular with posterolateral projections asymmetric, with concave posterior margin and relatively narrow apex (Fig. 6A). Segment X oblong-shaped, distinctly longer than wide. Cerci retracted, hardly visible in dorsal view. Imago. Not known. Diagnosis. Larvae of P. helenae sp. n. can be separated from other Palaearctic species by the combination of characters and comparative ratios shown in Table 1. Prosopistoma helenae sp. n. clearly differs from P. oronti and P. orhanelicum by the different number of antennal segments and the number of setae on right mandible (Table 1). The shape of carapace is similar in these species (Fig. 1), wider than long. However, the median part of posterior margin of carapace is convex in P. orhanelicum comparing to concave margin in P. helenae sp. n. and P. oronti and the ornamentation of the carapace is indistinct in P. helenae and P. orhanelicum comparing to distinct four-spotted dark brown ornamentation on anterior half of the carapace in P. oronti (Fig. 1). Absence of ornamentation on the carapace of P. helenae was apparent also on fresh material in 1989, when it was examined for the first time. The number of pectinate spines on foretibiae in older larvae is similar in P. helenae sp. n. and P. oronti and higher in P. orhanelicum.

NEW PALAEARCTIC PROSOPISTOMA Zootaxa 4018 (1) © 2015 Magnolia Press · 113 sp. n. sp. straight Prosopistoma alaini Prosopistoma ** ** Prosopistoma orhanelicum Prosopistoma * Prosopistoma oronti Prosopistoma sp. n. sp. . Prosopistoma 6 5 7 7 6 5 (1988): 23 larvae and parts on slides; Liban, l'Aouali au pont (Jisr) Bisri, v.–ix. 1979–1980; A. Dia leg., coll. T. Soldán Soldán T. coll. leg., Dia A. 1979–1980; v.–ix. Bisri, (Jisr) pont au l'Aouali Liban, slides; on parts and larvae 23 (1988): et al. 10–11 6–7 6–7 9–10 10–14 8–9 8–9 11–12 8–9 6–7 10–11 6–7 3 3 3 3–4 3–4 6–8 4–6 6–9 7–8 5 6–7 4–5 4–5 6–7 5–7 3 3 0.6–0.7 0.6–0.7 0.6–0.7 0.5–0.7 0.5–0.6 0.7–0.9 0.8–0.9 0.8–0.9 0.7–0.9 0.8–0.9 shallowly concave distinctly concave distinctly concave convex weakly concave, almost Prosopistoma pennigerum pennigerum Prosopistoma helenae Prosopistoma 6 1890) 5 (Vayssière reaching (1.05) equal reaching (0.8) shorter (1.3) longer not reaching not reaching shorter not reaching shorter (0.6) Comparison of the Palaearctic West species of the genus ** based on literature data (Dalkıran 2009) 2009) (Dalkıran data on literature based ** Ratio carapace width / length I gill of lamella of Apex 0.8–0.9 II gill of margin outer Lateral branching filaments major of No. I gill concave of lobe extended No. of pectinate spines on inner foretibia of margin VII-IX segments Abdominal 1.2–1.3 asymmetrically rounded angular straight symmetrically rounded symmetrically rounded round 1.1–1.2 lobe extended concave 1.1–1.4 angular concave 1.1 angular concave angular No. of setae on right mandible mandible on right setae of No. outer on teeth subapical of No. 7–8 margin of outer canine on inner teeth subapical of No. margin of outer canine on inner teeth subapical of No. canine II of I / seg. seg. of length Ratio maxillary palps I of II / seg. seg. of length Ratio palps labial 5 Shape of distal medial margin of carapace 7–9 7 8–9 TABLE 1. length body Total Ornamentation of carapace width/length head Ratio No. of antennal segments incl. distinct scape and pedicel Antenna reaching / mm not 4–6 reaching 2 head of margin anterior ratio III / antenna seg. Length flagellum of segments remaining indistinct 4 mm 3 distinct mm 3.5–4 2.3 indistinct 5.5 mm Thomas in described on material based * indistinct 2–2.5) (variability: 2.3 mm 4.1–4.7 2.1

114 · Zootaxa 4018 (1) © 2015 Magnolia Press BOJKOVÁ & SOLDÁN FIGURE 5. Gill I (left) and gill II (right) of larva. A—Prosopistoma helenae sp. n., B—Prosopistoma alaini sp. n., C— Prosopistoma pennigerum, D—Prosopistoma oronti, E—Prosopistoma orhanelicum (according to Dalkıran 2009).

NEW PALAEARCTIC PROSOPISTOMA Zootaxa 4018 (1) © 2015 Magnolia Press · 115 Larvae of P. helenae sp. n. have the same number of antennal segments reaching anterior margin of head as those of P. pennigerum, although antennal segment III is shorter in P. helenae sp. n. (Table 1). At a glance, they differed by the shape and ornamentation of carapace and abdominal segments VII–X. Carapace of P. helenae sp. n. is distinctly wider than long, with wide flange and apparently concave medial part of posterior margin, and without ornamentation (Figs 1, 2). Abdominal segments VII–IX have clearly round posterior margins and narrow apical parts of their lateral processes (Figs 1F, 6A). In contrast, the carapace of P. pennigerum is longer than wide, with narrower flange and only shallowly concave medial part of posterior margin (Figs 1C, 6D). Its ornamentation is typical, with darker orange-brown lateral parts of carapace and darker parts above wing pads forming two lobes forwards (Fig. 1C). This pattern is apparent also on younger larvae. Abdominal segments VII–IX have angular posterior margins and wide apical parts of their lateral processes (Fig. 6D). Further, they have different shape of the apical part of gill I, rounded in P. helenae sp. n. and extended to a lobe in P. pennigerum, and slightly different shape of gill II (Fig. 5). P. helenae sp. n. has fewer pectinate spines on foretibiae than P. pennigerum.

FIGURE 6. Detail of posterior part of carapace and abdominal segments VII–X. A—Prosopistoma helenae sp. n., B— Prosopistoma alaini sp. n., C—Prosopistoma orhanelicum (according to Dalkıran 2009), D—Prosopistoma pennigerum, E— Prosopistoma oronti.

Type material. Holotype: older larva (parts on slides); Iraq, Mosul Province, Tigris River in Mosul; 36°19'54.3"N, 43°09'04.6"E, 190 m a.s.l.; 29.–30. ix. 1989; T. Soldán leg. Paratypes: 12 larvae and parts on slides from the same locality as holotype. The material is deposited in the collection of Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. Type locality. Prosopistoma helenae sp. n. was collected in the Tigris River in Mosul near the bridge where the river channel was relatively wide (150–200 m) and formed islands, lagoons and short lateral channels (Fig. 7A). Larvae were not collected in the habitats with slow and uniform flow prevailing in the main channel of the river, but only in riffles and swift flow below an impoundment on lateral channel (Fig. 7B). The lateral channel was about 15–20 m wide and about 20–40 cm deep (max. depth about 1 m) with medium current velocity and turbid water. Larvae lived predominantly under cobbles sparsely overgrown with green algae, accompanied by larvae of Labiobaetis sp., Baetis gr. fuscatus, Serratella ignita and Caenis cf. luctuosa (no Heptageniidae or Leptophlebiidae were found). Etymology. The species is named after Helen Barber-James (Grahamstown, South Africa), an expert and enthusiast on the family Prosopistomatidae.

Prosopistoma alaini sp. n.

Larva. Notal shield (carapace) length along median suture 3.1 mm and total length of body 4.7 mm. Carapace slightly wider than long, width 1.1 x length; head width 2.1 x length and 0.6 times carapace width (Figs 1B, 8).

116 · Zootaxa 4018 (1) © 2015 Magnolia Press BOJKOVÁ & SOLDÁN Head: Head yellowish-brown unicoloured, antennae lighter. Compound eyes oval, blackish, slightly smaller than roughly oval lateral ocelli (Fig. 8). Epicranial suture well-visible, passing through posterior margin of lateral ocelli, and between compound eyes and antennal bases (Fig. 8A). Antennae 7-segmented, third segment markedly shorter (0.6 x times) than total length of segments IV–VII; antennae not reaching anterior margin of head (Fig. 9A). Mouthparts: Fore margin of labrum markedly convex in medial part and straight laterally, lateral parts fringed with long fine setae (Fig. 9A). Dorsal surface of labrum pitted. Outer canine of right mandible with three apical teeth equal in size; inner margin of outer canine with five teeth increasing in size towards apex and outer margin of outer canine with 5–7 wide teeth closely adjoining below (Fig. 9B). Inner canine of right mandible shorter and narrower than outer, with two short and wide apical teeth of similar size, four long acute teeth in outer margin of canine below apex and three long acute teeth in inner margin of canine below apex. Eight or nine long and serrated setae arise from base of inner canine, first anterior setae shorter than remaining setae. A field of rich setae and/or setal sockets medially to basally on mandible. Maxillae crowned by rigid canine and four subequal moveable dentisetae; three stout and mildly serrated setae near base of dentisetae, one long reaching length of dentisetae and two shorter of about one fifth of length of longer setae (Fig. 9C). Maxillary palps 3-segmented, segment II very narrow and long, distinctly longer than segment I (about 1.8–1.9 times). Labium typical of Prosopistomatidae (Fig. 9D). Labial palps 3-segmented, reaching front margin of labium. Labial palp segment II 0.8 times length of segment I, segment III 0.4 times length of segment II. Thorax: Carapace yellowish-brown, without any distinct markings, abdominal segments slightly brownish tinted (Fig. 1G). Wing pads and their basis of teneral subimago well-recognisable in mature larva (Fig. 1B). Carapace flange transparent but not apparently translucent, relatively wide. Posteromedial part of carapace weakly concave, almost straight (Figs 1G, 6B). Fore femora and coxa with ornamentation on dorsal surface consisting of scale-like structures; dorsal margin of femora with numerous fine and simple setae (Fig. 10). Ventral margin of fore tibiae with 8 large and pointed spines, with pectinate inner margins (with about 4–5 acute teeth) proximally following by 6–7 thin pointed spines (probably also pectinate), and with one long rounded seta on distal margin of tibiae; dorsal surface of tibia with about 20 double setae; ventral surface of tibia with about 10 long, stout pointed setae along entire length of tibia. Foretarsus with several long pointed setae along both dorsal and ventral margins and on dorsal surface. Lamella of gill I apically extended into a lobe; mature larva with about 8–9 major filaments branching of gill I (Fig. 5B). Gill II rectangular (ratio width/length 0.8), posterior margin and outer lateral margin concave, inner lateral margin distinctly convex. Abdomen: Anterior part of abdominal segment VII covered by carapace; abdominal segments VII–IX apparently angular with straight posterior margins; posterolateral projections nearly symmetric, with straight inner margins and relatively wide apices (Figs 1G, 6B). Segment X rectangular, wider than long. Cerci retracted, not visible in dorsal view.

FIGURE 7. Tigris River, the type locality of Prosopistoma helenae sp. n. A—stream channel at the type locality, B—habitat where the type material was collected. (photos T. Soldán).

Diagnosis. Larvae of P. alaini sp. n. can be told apart from other Palaearctic species by the combination of characters and comparative ratios shown in Table 1. Carapace of Prosopistoma alaini sp. n. is wider than long like in P. orhanelicum, P. oronti and P. helenae sp. n., but with weakly concave, almost straight, medial part of posterior margin and posterior margin of carapace gently slopes rearwards covering anterior half of abdominal segment VII (Figs 1, 6). Unlike P. oronti and P. pennigerum, it has no distinct ornamentation. The number of antennal segments is higher than in P. pennigerum, P. helenae sp. n. and P. oronti and despite high number of antennal segments, antennae do not reach anterior margin of head (Fig. 7A). Further, P. alaini sp. n. differs in the number of setae on right mandible and pectinate spines on foretibiae (Table 1). Larvae of P. alaini sp. n. are the most similar to those of P. orhanelicum; common features include the number of antennal segments not reaching anterior margin of head, no distinct ornamentation on carapace and angular abdominal segments VII–IX (Table 1). P. alaini sp. n. has more setae on right mandible, different shape of inner canine of mandible (short and wide apical teeth) and gill I (lamella with extended apex and much less rich branching; Fig. 5), and almost straight posterior margin of carapace (comparing to convex carapace of P. orhanelicum, Fig. 6). The number of spines on foretibiae is high in both species, but probably higher in P. alaini sp. n. Mature larva of P. alaini sp. n. has eight thick pectinate spines that are followed by six or seven thin setae in the proximal third of foretibiae (Fig. 9). Mature larva of P. orhanelicum has up to nine, rarely ten, spines which are both pectinate and simple according to Dalkıran (2009) (six thick pectinate spines followed by several simple thin spines were depicted).

118 · Zootaxa 4018 (1) © 2015 Magnolia Press BOJKOVÁ & SOLDÁN FIGURE 9. Prosopistoma alaini sp. n., A—head of larva as seen flattened under a compound microscope preparation, B— right mandible, C—right maxilla, D—labium, left ventral view, right dorsal view.

NEW PALAEARCTIC PROSOPISTOMA Zootaxa 4018 (1) © 2015 Magnolia Press · 119 FIGURE 10. Prosopistoma alaini sp. n., foreleg of larva with enlargement of scales covering the surface of coxa and femur and pectinate setae on tibia.

Type material. Holotype: mature larva (parts on slides); Oued Isser, Sidi Abdelli; 300 m a.s.l., 16. vi. 1982; J. Gagneur leg. Grid reference of the type locality is not available. Paratypes: 1 mature larva and 1 mature larva on slides from the same locality as holotype. Deposited in the collection of Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. Etymology. The species is named after Alain G.B. Thomas (Toulouse, France), an outstanding expert on the North African aquatic fauna and mayflies in general. Remarks. Prosopistoma alaini sp. n. is known only from Oued Isser in Algeria. Material collected in Oued Tizguid near Ifrane in the Middle Atlas Mountains in Morocco (Touabay et al. 2002) could belong to this species as well. We visited Oued Tizguid below Ifrane in May 2014, however, we did not find any specimen of Prosopistoma there. The species could be extirpated due to strong water pollution there.

Prosopistoma pennigerum (Müller, 1785)

Larva. Notal shield (carapace) length along median suture 3–4 mm and total length of body 5–6 mm in ultimate and penultimate instars. Carapace longer than wide, width 0.8–0.9 x length; head width 2 x length and 0.6 times carapace width (Fig. 1C). Head: Head yellowish-brown unicoloured, antennae lighter. Compound eyes oval, blackish, slightly smaller than triangular lateral ocelli. Epicranial suture well-visible, passing through posterior margin of lateral ocelli, and between compound eyes and antennal bases. Antennae 6-segmented, third segment of similar length (1.05 x times) as total length of segments IV–VI; antennae reaching anterior margin of head.

120 · Zootaxa 4018 (1) © 2015 Magnolia Press BOJKOVÁ & SOLDÁN Mouthparts: Fore margin of labrum convex in medial part and straight laterally, with short fringe of thin setae. Dorsal surface of labrum pitted. Outer canine of right mandible with three apical teeth equal in size (inner tooth slightly longer); inner margin of outer canine with 6–7 teeth increasing in size towards apex and outer margin of outer canine with 6–8 wide teeth closely adjoining below. Inner canine of right mandible shorter than outer, with two wide apical teeth of subequal size and three long and acute teeth below apex. Seven or eight long and serrated setae arise from base of inner canine; first anterior seta shorter than remaining setae. A field of rich setae and/or setal sockets medially to basally on mandible. Maxillae crowned by rigid canine and four subequal moveable dentisetae; three mildly serrated setae near base of dentisetae. Maxillary palps 3-segmented, segment II narrow and long, distinctly longer than segment I (1.6–1.7 times). Labium typical of Prosopistomatidae. Labial palps 3-segmented and long, markedly extending front margin of labium. Labial palp segment II 0.8 times length of segment I, segment III 0.5 times length of segment II. Thorax: Carapace yellowish-brown, lateral parts milky; distinct brownish heart-shape pattern on carapace (Fig. 1C), noticeable also on smaller larvae. In mature larvae, ornamentation strengthened by dark bases of wings of teneral imago visible through carapace (Fig. 1C). Posteromedial part of carapace shallowly concave (Fig. 6D). Fore femora and coxa with reticulate pattern on dorsal surface consisting of scale-like hexagonal or pentagonal structures; dorsal margin of femora with over 20 fine and simple setae. Ventral margin of fore tibiae with 7 large and pointed spines with pectinate inner margins (with about 6–7 acute teeth) proximally followed by 3–4 thin and pointed spines, probably also pectinate. One long, rounded and stout seta with pectinate inner margin on distal margin of tibiae. Dorsal margin of tibiae with numerous double setae; ventral surface of tibia with 4–5 stout pointed setae. Fore tarsus with several long pointed setae along both dorsal and ventral margins and on dorsal surface. Lamella of gill I apically extended into evident lobe, mature larva with about 8–9 major filaments branching of gill I (Fig. 5C). Gill II rectangular (ratio width/length 0.75), posterior and outer lateral margins evidently concave, inner lateral margin distinctly convex (Fig. 5C). Abdomen: Abdominal segments VII and IX apparently angular with straight posterior margins; posterolateral projections nearly symmetric, with straight (or slightly convex) posterior margins and relatively wide apices (Figs 1C, 6D). Segment X oblong-shaped, apparently wider than long. Cerci retracted, usually little distinguishable in dorsal view. Material examined. 2 larvae (one dissected); Portugal, Río Támega, Frariz; 28. ix. 1983; L. S. W. Da Terra leg. 3 larvae (two dissected for study of internal organs in Landa 1969a); Hungary, Maros River; Szeged; M. Straškraba leg. 1 larva (on slides); France (Dept. Haute-Garonne), Garonne River above Cavaletade (Toulouse); July 1928; R. Despax leg. Deposited in the collection of V. Landa, Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.

Discussion

In the West Palaearctic region, Prosopistoma pennigerum is the most widespread species, although the majority of records are historic. Published records are known from the Iberian Peninsula (Portugal, Spain) and west and south Europe (France, Netherlands, Luxembourg, Italy) through central Europe (Germany, Czech Republic, Hungary) to east Europe (Macedonia, Romania, Greece). The northernmost records are from south Sweden and Latvia and the easternmost records are known from west Russia, east Turkey and Georgia (Schletterer & Füreder 2009; Bauernfeind & Soldán 2012). Morphological variability of the species across its large area is poorly known. A French population of the species was subjected to detailed morphological description (Vayssière 1881, 1882, 1890; Lafon 1952) and less detailed information is available from central and east Europe (Latvia–Katschalova 1965; Czech Republic and Hungary—Landa 1969a,b). We examined specimens from distant populations from Portugal and France and Hungary and we did not find any apparent variability in the main morphological characters of

NEW PALAEARCTIC PROSOPISTOMA Zootaxa 4018 (1) © 2015 Magnolia Press · 121 larvae between these populations and also when comparing with published information (Vayssière 1890; Katschalova 1965; Landa 1969a,b). However, we did not have any material from eastern part of species area, where P. pennigerum was recorded at present (Volga River, Schletterer & Kuzovlev 2007) or in the past (Tigris River, Koch 1985; Kura River, Sadovsky 1946). New morphometric analyses of larvae of all available Prosopistoma species by Barber-James (2010) showed certain differences in specimens from Spain and France from Russian ones and the author emphasized the necessity to examine material from different sites across species area to confirm/exclude it is more than one species here (see also Barber-James 2009). West-Palaearctic species of the genus Prosopistoma are distinguishable particularly based on the number and length of antennal segments, characters on right mandible, shape and ornamentation of carapace, number of pectinate spines on foretibiae, and shape of gills I, II and abdominal segments VII–X (Table 1). In contrast, several characters important for distinguishing species from other regions are similar in all species studied, for example the shape of maxilla, proportions of segment I / segment II of labial and maxillary palps, convexity of carapace. Many important characters, such as number of setae and teeth on mandibles, spines on foretibiae, antennal segments, and shape and branching of gill I, are variable in the course of larval growth (e.g. Thomas et al. 1988; Dalkıran 2009). Thus, it is necessary to examine only ultimate or penultimate instars of larvae. Although this study is not based on extensive material, only mature or almost full-grown larvae were described. Naturally, it was not possible to obtain further material from such inaccessible countries like Algeria and Iraq and we failed to collect any Prosopistoma during our field trip throughout Morocco in 2014. The new species P. alaini from North Africa is closely related to the West-Palaearctic species and distant from Afrotropical species which is in accordance with proposed lineages of Prosopistoma by Barber-James (2009). The second described species P. helenae represents a record from the eastern half of West Palearctic region which seems to be now rather isolated and further new species could be found there.

Acknowledgements

We are grateful to A. G. B. Thomas (Toulouse) who provided us with valuable material from Algeria a good many years ago and J. Gagneur who collected this material. We also thank to Kateřina Bláhová (Biology Centre CAS, Č. Budějovice) for help with drawings.

References

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