Procloeon strumiferum Chen & Zhou 2023, sp. n.
Creators: name: Chen, Xiao-Fang
name: Zhou, Chang-Fa
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Procloeon
Procloeon strumiferum

description: (3) Procloeon strumiferum sp. n.
(Figs 1A, 1D, 2E–F, 3C, 3F, 4C, 4F, 5E–F, 6E–F, 6H, 6J, 7G–I, 8A–F, 9D–H, 10A–B)
Material examined: Holotype: China: male imago (reared), 1.5 km upstream creek to Huanglongjia Reservoir, Hongwei Forest Farm, Jiangning District, Nanjing City, Jiangsu Province (118°96′82″E, 31°97′17″N), 11.VI.2022, Changfa Zhou, Dewen Gong, Xinhe Qiang, Mengyao Li and Muhe Deng; Paratypes: 5 nymphs, 2 female imagoes (reared), 3male imagoes (reared), same as the holotype; 5 nymphs, same place as the types, 27.IX.2022, Changfa Zhou; 3 female imagoes (reared), 2 male imagoes (reared), 1.0 km upstream of Explorsion Park, Zijin Mountain, Nanjing City, Jiangsu Province (118°84′88″E, 32°02′35″N), 22.IX.2022, Chang-Fa Zhou.
Mature nymph (in alcohol): Body length 4.0–5.0 mm; antennae 2.4–2.6 mm; terminal filament 1.7–1.9 mm, cerci 1.8–2.0 mm. Body pale with various brown to chocolate dots and markings (Fig. 5E). Antennae pale, scape subequal to pedicel in length. A pair of brown stripes on vertex to clypeus. Mouthparts similar to P. chinensis except: (1) anterior margins of labium slightly convex (Fig. 8F); (2) maxillary palpi two-segmented, segment I: II 0.6: 1.0 (Figs 4F, 8C); (3) inner margin of segment III of labial palpi slightly less convex (Fig. 4C). Mandibles and hypopharynx are similar to the former species P. chinensis (Figs 8B, D–E).
Thorax: Width: length of pronotum 3.0: 1.0, with irregular brown markings (Fig. 5E). Hindwing pads visible. Legs pale, femur with subapical band (Fig. 6E). Length ratio of forefemur: tibia: tarsus 1.4: 0.8: 1.0, ratio of mid- and hindlegs 1.8: 1.0: 1.0. Claw ca. 0.5x tarsus (Fig. 6F); each claw with two row of denticles on basal half, progressively larger from base to apex (Figs 7G–H).
Abdomen: Terga III, VI and IX darker than others, each of them with a pair of pale submedian stripes; other terga pale, with irregular brown to dark markings (Fig. 5E). Terga I–X and sterna V–IX with spines on posterior margins; terga III–X with sharp posterolateral spines; terga VIII and IX with lateral spines; terga and sterna with reddish line on posterior margins, usually divided into two parts (Figs 5E–F). Sterna with lateral brown patches (Fig. 5F). Gills on terga I–VII; gills I–V with double lamellae but gills VI–VII single (Figs 9E–H); ventral lamellae of gills I–VII nearly peltate, but dorsal lamellae of gills I–V nearly elongate and gradually shortened (Figs 9E–F); margin of gill VII with very sparse tiny hair-like setae (Fig. 9D); tracheae of gills dark and contrasting. Paraproct with 8–9 marginal spines (Fig. 6H). Caudal filaments pale yellowish, with reddish ring and a ring of denticles on every fourth segments (Fig. 6J), a contrasting brown band present subapically; spine pattern similar to P. chinensis.
Male imago: Body length 5.0–6.0 mm, forewings 4.0–5.0 mm, hindwings 0.2–0.3 mm, cerci 10.0–12.0 mm. Head: antennae pale (Fig. 10A), the upper portion of compound eyes pale to pale orange, their apices broader than base; lower portion gray. Thorax: pale to yellowish (Fig. 2E). All legs uniformly pale. Length ratio of femur: tibia: tarsus of foreleg 0.8: 1.0: 1.0, tarsal segments 1–5 arrangement from long to short as 2, 3, 4, 5, 1. Apex of tibia slightly broadened. Length ratio of femur: tibia: tarsus of midleg 1.3: 1.2: 1.0, tarsal segments 1–3 arranged in decreasing order as 3, 1, 2. Length ratio of femur: tibia: tarsus of hindleg 1.2: 1.2: 1.0, tarsal segments 1–3 arranged in decreasing order as 3,1, 2. All legs with one acute and one blunt claw. Forewings transparent while base of C, Sc and R1 pigmented with brown, subcostal brace light brown; 7–10 crossveins at pterostigma region; length of marginal intercalaries subequal to distance between them and neighboring longitudinal veins (Fig. 1A). Hindwings small, costal margin slightly convex, lack costal projection and veins (Fig. 1D). Abdomen: terga I–VI translucent, terga VII–X pale to yellowish; posterior margins of each tergum with two transverse lines, tergum IV and sometimes VII with additional a pair of oblique reddish stripes (Fig. 2E). Segment I of forceps slightly widened apically, segment II with a depression near base, its apex slightly expanded; segment III enlarged apically (Figs 3C, F), length 2.7x width. Cerci pale (Fig.10A).
Female imago: Body length 5.0–6.0 mm, forewings 4.0–5.0 mm, hindwings 0.3–0.5 mm, cerci 10.0–12.0 mm. Coloration similar to male (Fig. 10B). Length ratio of femur: tibia: tarsus of foreleg 1.0: 0.9: 1.0, tarsal segments 1–5 arrangement from long to short as 2, 3, 4, 5, 1. Apex of tibia slightly broadened. Length ratio of femur: tibia: tarsus of midleg 1.3: 1.2: 1.0, tarsal segments 1–3 arranged in decreasing order as 3, 1, 2. Length ratio of femur: tibia: tarsus of hindleg 1.2: 1.2: 1.0, tarsal segments 1–3 arranged in decreasing order as 3,1, 2.
Egg: Oval, with regular papillae (Fig. 7I).
Diagnosis. The new species P. strumiferum sp. n. can be distinguished from congeners by the combination of the following diagnostic characters. Nymph: maxillary palpi two segmented, length ratio from base to apex 0.6: 1.0 (Figs 4F, 8C); gills I–V with double lamellae but gills VI–VII single (Figs 9E–H); claw about 1/2 length of respective tarsus and widened at base (Figs 6E–F).
Adults of P. strumiferum sp. n. have tiny hindwings, which have no costal projection or visible veins (Fig. 1D). Forceps of males’ strumiferum are unique in having relatively widened segment I and elongated segment III (Figs 3C, F). The color pattern of abdomen (terga with two reddish lines on posterior margins and terga IV with a pair of oblique stripes) is useful to identify both males and females (Figs 2E–F).
Another species Procloeon albisternum (Novikova, 1986) (in Tshernova et al. 1986) also has two segmented maxillary palpi. But it can be differentiated from our new species P. strumiferum sp. n. by single gills IV in nymphal stage. In addition, the adults of it have costal projection of hindwings. In contrast, our new species has a long-oval hindwings, which has no projection.
Distribution. China (Jiangsu Province).
Etymology. The specific name of this species “ strumiferum ” (neutral) comes from Latin word “ strumifer ” (having tubercle), indicating the basal segment of male forceps with tubercle-like projections.
description: Published as part of Chen, Xiao-Fang & Zhou, Chang-Fa, 2023, A contribution to knowledge of Procloeon Bengtsson, 1915 from the Chinese mainland (Ephemeroptera: Baetidae) with description of a new species, pp. 163-175 in Zootaxa 5353 (2) on pages 171-173, DOI: 10.11646/zootaxa.5353.2.6, http://zenodo.org/record/8427226