Phanoperla constanspina, Dela Cruz, Ian Niel B., Nuñeza, Olga M. & Lin, Chung-Ping, 2016

Dela Cruz, Ian Niel B., Nuñeza, Olga M. & Lin, Chung-Ping, 2016, Description of a new Oriental stonefly species, Phanoperla constanspina (Plecoptera: Perlidae) from Mindanao, Philippines and association of life stages using DNA barcoding, Zootaxa 4193 (1), pp. 102-116 : 104-108

Phanoperla constanspina sp. nov. dela Cruz, Nuñeza, and Lin

( Figs. 1–11 )

Material examined: Philippine Islands, Mindanao, Mt. Malindang , Layawan River . Holotype male, 185 masl, N 08°25.418’ E 123°41.806’, 3 October 2013 (A-G23.m) . Paratypes 5 males: 1 male, 336 masl, N 08°23.690’ E 123°40.056’, 1 October, 2013 (A-E23.m); 4 males, 161 masl, N 08°25.971’ E 123°42.492’, 4 October 2013 (A- H7.m, A-H11.m, A-H12.m, A-H16.m). Nymphal paratypes 3 males: 185 masl, N 08°25.418’ E 123°41.806’, 3 October, 2013 (N-G49.m); 161 masl, N 08°25.971’ E 123°42.492’, 4 October, 2013 (N-H27.m); 73 masl, N 08°27.290’ E 123°44.697’, 6 October, 2013 (N-J26.m). Nymphal paratypes: 2 males, 3 females, 956 masl, N 08°19.417’ E 123°38.017’, 16 April 2014 (N-B30.f); 1 male at 264 masl, N 08°24.452’ E 123°40.887’, 2 October 2013 (N-F20.f). The Holotype is deposited in the collection of the Natural Science Museum, MSU-IIT, Philippines and paratypes in the Insect Collection, National Museum of Natural Science, Taichung , Taiwan ( NMNS) . All specimens were collected and prepared by INDC .

Adult habitus. General color brown, sometimes appearing dark brown when membranous dark wings fold flat at rest. Head wider than pronotum, bearing a distinctive stretched M-shaped pattern, appearing to be paler to surrounding area ( Figs. 1 A and 1B). Frons with dark brown pigment along occipital line and ridge ( Fig. 1 A). Compound eyes bulging, relatively large. Ocelli of 0.76 ± 0.1 mm in diameter in males and 1.0 ± 0.0 mm diameter in females, with lateral inner dark rings. Median occipital line conspicuous and well-marked. Median suture forms a bare depression with raised margins. Antennae and palpi pale brown basally, distally dark. Pronotum rectangular with rounded corners, dark lines occur on margins and median suture, rugosities conspicuous on pronotum. Smaller hairs cover pronotum and most of the head. Wings brown and slightly infuscated with dark venation ( Figs. 2 A and 2B). Legs dark brown from the proximal half of femora towards tibia and tarsus ( Fig. 3 ). Small thorn-like hairs present particularly on femoral margins.

Male. Body length 9.12 ± 0.51 mm, forewing 9.35 ± 0.47 mm, hindwing 8.25 ± 0.2 mm. Width of head at pronotum 1.62 ± 0.13/1.5 ± 0.1 mm ( Fig. 1 A). Femur 1.91 ± 0.03 mm, tibia 2.28 ± 0.06 mm, tarsus 0.62 ± 0.03 mm ( Fig. 3 ). Brushes of long setae on abdominal sternites S4-S8, usually strongest on S5-S7 ( Fig. 4 ). Tergites simple (T7 and T8), T9 with a median depression but slightly raised at sides with short conical-shaped setae ( Fig. 5 ). Anterior process of the hemitergite unbranched and of variable shape ( Fig. 5 ). Penial capsule short, 0.76 ± 0.1 mm, but tubular at base, faintly sclerotized for muscle attachment ( Fig. 6 ). Everted sac almost equal to penial tube in length and armed with small jet-black posterior spines, fewer and becoming shortest towards the base ( Fig. 6 ). Apex of the sac cylindrical and black covered with short and fine black hair-like spines of uniform length on anterior surrounding structure ( Fig. 6 ).

Female. Body length 12.6 mm, forewing 12.46 mm, hindwing 12.1 mm. Head/pronotum width 2.23/ 2.09 mm ( Fig. 2 A). Femur 2.06 mm, tibia 2.69 mm, tarsus 0.85 mm. Subgenital plate undeveloped, displaying a simple posterior margin on S8.

Egg. General outline droplet-shaped, somewhat elongated, and very similar to P. batac ( Fig. 8 A). Total length ca. 522.98 ± 0.06 µm and equatorial width ca. 198.6 ± 0.12 µm, with long and slender collar with a length of 137.75 ± 0.23 µm. Rugose processes are observed on the collar extension while the apex is flanged with a cork-like rim ( Fig. 8 C). Chorionic surface even and simple but with few, fine punctations ( Fig. 8 B) around the subapical ring of the anterior end ( Fig. 8 D).

Nymphal habitus. Females are considerably larger than males. General pigment pattern variable in mature individuals, ranging from light to dark brown and sometimes black with varying hues and pigment intensity on a few structures such as tips of wingpad and tergal margins ( Figs. 11 A and 11B). Heads always with darker frons and paler M-line pattern, which is evident on the adults. Well-marked horizontal suture separating labrum from head, making a protruding labrum slightly noticeable. Pronotal disc usually wider than head, occipital ridge positioned more forward from posterior margin of head base ( Figs. 11 A and 11B). Pronotum oval-shaped. Wingpads medium and simple. Abdomen slender relative to body size with obvious stripes separating terga from each other ( Figs. 11 A and 11B). Antennal flagellum long and setaceous, cercus medium-sized and bearing short, stiff hairs. Basal attachment of cerci is a little plump extending wide from the base of T10 while the apical tip becomes thin. Mandible ovate, base plumper than the rest of the structure ( Fig. 9 ). Teeth uneven in length and size, slightly bent towards the inner side, brushes of bristled hair present laterally and adjacent to the shortest tooth on the apex. Leg completely light brown with numerous fine and long lateral tibial and femoral hairs ( Fig. 10 ). Thorn-like hairs sparsely distributed on the proximal half of the femur and sometimes along tibial margins, but none on the tarsus.

Male nymph. Body length 10.52 ± 0.58 mm, abdominal length 4.75 ± 0.32 mm ( Fig. 11 A and 11B). Width of head/pronotal disc 2.12 ± 0.12/2.22 ± 0.16 mm ( Fig. 11 A and 11B). Ocelli 1.06 ± 0.28 mm diameters apart. Mandible 0.74 ± 0.03 mm ( Fig. 9 ). Mesothoracic and metathoracic width 2.53 ± 0.14 mm and 2.43 ± 0.36 mm, respectively. Femur 1.67 ± 0.19 mm, tibia 1.59 ± 0.13 mm, tarsus 0.8 ± 0.07 mm ( Fig. 10 ). Cercus 3.53 ± 0.35 mm.

Female nymph. Body length 14 ± 0.98 mm, abdominal length 6.54 ± 0.46 mm. Width of head against pronotal disc 2.73 ± 0.25/2.94 ± 0.17 mm, ocelli 1.5 ± 0.23 mm diameters apart, mandible 1.06 ± 0.07 mm. Mesothoracic and metathoracic width 3.31 ± 0.26 and 3.19 ± 0.28 mm, respectively. Femur 2.14 ± 0.35 mm, tibia 2.02 ± 0.29 mm, tarsus 1.02 ± 0.15 mm. Cercus 4.29 ± 0.48 mm.

Habitat. Adults of P. constanspina were collected from Layawan River (alt. 73–1,218 masl) of Mt. Malindang, northern Mindanao, Philippines. This fast flowing river has an average width of approximately 10 m, depth of 80 cm and is canopied with forest trees of mainly dipterocarps and palm species, as well as shrubs near the riverbank. Nymphs of P. constanspina are often sympatric with Neoperla species occurring under small to medium-sized cobbles, or can be found in leaf pack litter accumulated on rocks in fast currents.

Etymology. The species name refers to the constant array of fine, spine-like hairs of uniform length covering the apical tip of penial sac.

Association of sexes and life stages. The pairwise distances of CO1 barcode sequences between males and presumptive female of P. constanspina revealed 100% similarity (no sequence divergence), suggesting that they belong to the same species. Between adults and presumptive nymphs, the sequence divergence is 0%, showing both life stages belong to the same species (see Table 2).

Diagnosis. The new species is a member of the P. anomala species complex and morphologically most similar to P. bakeri , known from the Philippines and Borneo. Similarities between P. constanspina and P. bakeri are in the structure of the penial capsule with a short, plump and unbranched penial tube. However, the everted sac of P. constanspina is distinguished by a blackened and rounded apical tip covered by small, spine-like hairs surrounding and covering the apex, where the jet-black hooks are positioned posteriorly forming a triangular shape, but with fewer hooks towards the base. Phanoperla constanspina has a droplet-shaped egg with long, slender collar, which

Figures

FIGURES 1. Phanoperla constanspina sp. nov. head and pronotum. (1 A) Male adult, indicating occipital line. (1 B) Female adult. Scale = 1.00 mm.

FIGURE 2. Phanoperla constanspina sp. nov. male wing. (2 A) Right forewing, showing the forking of Cu 2 from Cu 1. (2 B) Right hindwing. Scale = 1.00 mm.

FIGURES 3 – 4. Phanoperla constanspina sp. nov. male. (3) Right foreleg. (4) Abdominal sternite showing hair brushes on each segment (S 5 – S 8). Penial capsule visible on S 9. Scale = 1.00 mm.

FIGURE 5. Phanoperla constanspina sp. nov. male dorsal terminalia showing the hemitergal (arrow) and paired clumps of short setae located on medial tergum 9. Scale = 1.00 mm.

FIGURE 6. Phanoperla constanspina sp. nov. penial tube showing the everted penial sac at the base. Scale = 0.2 mm.

FIGURE 7. Phenotypic variation of six adult male Phanoperla constanspina sp. nov. based on the shape and structure of hemitergites (HT) and unbranched anterior process (AP), adorned with variable short setae on tergum 9. (A) (Haplotype: A- G 23. m) Medium-sized AP, body and slightly bent on the pointed apex, setal patches isolated from each other. (B) (Haplotype: A-H 7. m) AP small and pointed, setae located above the apical tip adjacent to each other. (C) (Haplotype: A-H 16. m) Plump base and small AP (Fig. 5), with slightly pointed tip, paired setal patches adjacent and overlapping. (D) (Haplotype: A-H 12. m) Medium and longer AP, bent on the inner side near the apex, setal patches fused, distributed along and near the process. (E) (Haplotype: A-E 23. m) AP blunt on the tip in a medium-sized body, setal patches adjacent. (F) (Haplotype: A-H 11. m) HT and AP broad and plump, resembling a hook-like structure at the tip, setal patches adjacent.

FIGURE 8. Phanoperla constanspina sp. nov. egg. (A) Entire egg. (B) Chorionic details. (C) Collar end (D) Anterior end. Scale = 100 µm.

FIGURES 9 – 10. Phanoperla constanspina sp. nov. male nymph. (9) Right mandible. (10) Right foreleg. Scale = 0.5 mm.

FIGURE 11. Phanoperla constanspina sp. nov. male nymphal habitus illustrating two general body pigmentation types. (A) (Haplotype: N-J 25. m) Pale to lighter brown, sometimes with darker wingpad tips. (B) (Haplotype: N-G 49. m). Dark to darker brown, sometimes with dark to black wingpads.