Prosopistoma pennigerum (Müller, 1785), Muller, 1785

Bojková, Jindřiška & Soldán, Tomáš, 2015, Two new species of the genus Prosopistoma (Ephemeroptera: Prosopistomatidae) from Iraq and Algeria, Zootaxa 4018 (1), pp. 109-123 : 120-121

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. 1 C).

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.

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. 1 C), noticeable also on smaller larvae. In mature larvae, ornamentation strengthened by dark bases of wings of teneral imago visible through carapace ( Fig. 1 C). Posteromedial part of carapace shallowly concave ( Fig. 6 D).

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. 5 C). Gill II rectangular (ratio width/length 0.75), posterior and outer lateral margins evidently concave, inner lateral margin distinctly convex ( Fig. 5 C).

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 1 C, 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.

Figures

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).

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).

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.