Neoperla obliqua, Banks 1913

Dela Cruz, Ian Niel B., Nuñeza, Olga M. & Lin, Chung-Ping, 2018, A new record of Neoperla obliqua Banks, 1930 (Plecoptera: Perlidae) from Mt. Malindang, Mindanao, Philippines and association of life stages using DNA barcodes, Zootaxa 4514 (1), pp. 145-150 : 146-147

Neoperla obliqua, Banks 1913

Material examined. Philippines, Mindanao, Mt. Malindang, Layawan River . 1 ♂, 127masl, N 08°26.314’ E 123°42.492’, 5 October 2013; 3 ♀, 185masl, N 08°25.418’ E 123°41.806’, 3 October 2013. 185masl, N 08°25.418’ E 123°41.806’, 3 October 2013; 1 ♀ nymph, 1,218masl, N 08°18.495’ E 123°37.980’. All material is deposited in the Natural Science Museum, MSU-IIT, Iligan City , Philippines.

Ova. Shape oval, highly striated, ( Fig. 1A ). Collar present but flat. Length ca. 318.16 ± 10.37 µm (n=3), equatorial width ca. 222.63 ± 4.97 µm. Collar bare, with length ca. 16.2 ± 8.5 µm and width ca. 85.83 ± 9.7 µm, with uneven surface, resembling a lid ( Fig. 1C ). Chorionic surface rugose and somewhat ornate. Gyral structure irregular but usually follows a longitudinal ridge-like pattern which arises from the collar end, creating a sulci or irregular grooves in between studded with pores of almost similar sizes ( Fig. 1D ). Micropyles at distal end of the collar and present in all ova examined ( Fig. 1B ).

Nymph. General color golden ochre to pale orange, while darker, usually dark brown to black margins on frons and labrum of head, the pronotal disc, tip of wingpads, and abdominal terga ( Fig. 2A ). Pronotal disc ovalshaped. Wingpads not elongated. Terga faintly striped. Antennae and cerci setaceous. Mandible ochre, ovateshaped but broad on its base possessing a five comb-like, blunted teeth of irregular sizes ( Fig. 2B ). Few fine setal hairs on the inner edges of mandible. Legs golden-brown without acute setal surface hairs ( Fig. 2C ).

Female nymph. Body length of 17.44 mm (n=1), abdominal length 7.02mm. Width of head is 4.01mm, pronotal disc is 3.91mm. Ocelli 0.8mm diameters apart. Mandible 1.43 mm. Mesothoracic and metathoracic width 4.36 mm and 4.07 mm, respectively. Antenna 11.05 mm. Femur 4.13 mm, tibia 3.94 mm, tarsus 1.22 mm. Cercus 9.78 mm.

Habitat. Adults of N. obliqua were sympatric with another unidentified perlid stonefly species. The single nymph of N. obliqua was found under large rocks in the Layawan River, in a section with moderate current.

Life stage and sex association. Pairwise CO1 sequence comparisons revealed 0.2% intraspecific divergence between males and females of putative conspecifics. The sequence similarity between adult and nymphal stages was 99.9 ± 0.14% ( Table 2). Comparisons between divergences of interspecific CO1 sequences of all available perlid stoneflies based on Kimura-2-parameter (K2P) model were also shown ( Table 3).

Figures

FIGURE 1. Neoperla obliqua ova. (1A) Entire ova. (1B) Chorionic details (arrow refers to micropyle). (1C) Collar end. (1D) Anterior end. Scale = 100µm.

FIGURE 2. Neoperla obliqua ♀ nymph. (2A) Nymphal habitus. (2B) Right mandible. (2C) Right foreleg. Scale = 1.00 mm, except for mandible which is 0.5 mm.