Neoperla mindoroensis, Pelingen & Freitag, 2020

Pelingen, Arthien Lovell & Freitag, Hendrik, 2020, Description of Neoperla mindoroensis sp. nov., the first record of a stonefly from Mindoro, Philippines (Plecoptera, Perlidae), and identification of its life stages using COI barcodes, ZooKeys 954, pp. 47-63 : 47

Neoperla mindoroensis sp. nov.

Type locality.

Philippines • Oriental Mindoro, Municipality of Roxas, Barangay San Vicente: Quirao Buhay Creek tributary Tagugoy Creek; secondary forest, ca 12°36'30"N, 121°22'38"E, ca 200 m asl.

Material.

Holotype: 1 ♂ adult (NMP), labelled "PHIL: Or[iental]. Mindoro, Roxas, Brgy. San Vicente, Quirao \ Buhay tributary, Tagugoy Creek; secondary forest; \ 12°36'30"N, 121°22'38"E 200 m a.s.l.; leg. AL Pelingen, \ C Pangantihon, H Freitag 05 Feb. 2018 (HBT)L", preserved in a cryovial with 95% ethanol, right hindleg and all left legs missing as used for DNA extraction (PL50), both cerci partially broken, tips of wings partially broken, dissected aedeagus stored inside the same vial. Paratypes: Philippines • 1 ♂ adult; HBT E; 12 Aug.-21 Sept. 2018; leg. Freitag & Pangantihon; NMP; left midleg and hindleg missing, both cerci partially broken, dissected aedeagus stored inside the same vial • 1 ♂ adult; HR3 E; 15 Jan.-17 Feb. 2019; leg. Pangantihon; ZMB; both cerci partially broken, dissected aedeagus stored inside the same vial • 1 ♀ adult; TDR1 L; 08 May 2018; leg. Freitag and Pangantihon; NMP; right legs used for DNA extraction (PL22), both cerci partially broken, eggs used for SEM • 1 ♂ nymph; TDR1f; 22 Sept. 2019; submerged wood in run; leg. Freitag and Pangantihon; AdMU; dissected mouth parts stored in the same vial • 1 ♀ nymph; TDR3f; 08 Feb. 2018; submerged wood in run; leg. Freitag; NMP; left midleg and hindleg used for DNA extraction (PL21); left foreleg broken but stored in the same vial, both cerci partially broken • 1 ♂ adult; TDR3/TBC L; 08 May 2018; leg. Freitag & Pangantihon; CAP-AdMU; right and left midlegs broken but stored inside the same vial, both cerci partially broken, dissected aedeagus stored inside the same vial • 1 ♀ adult; TDR3/TBC L; 08 May 2018; leg. Freitag & Pangantihon; AdMU; left hindleg missing, both cerci partially broken, right forewing broken but stored in the same vial • 1 ♀ adult; THC E; 19 Nov.-02 Dec. 2018; leg. Freitag; ZMB; both cerci broken • 1 ♂ adult; TIR E; 24 Jan.-16 Feb. 2018; leg. Pangantihon; ZMB; right cercus partially broken, dissected aedeagus stored inside the same vial • 1 ♂ adult; TIR E; 24 Jan.-16 Feb. 2018; leg. Freitag; AdMU; left hindleg missing, both cerci partially broken, tips of wings partially broken, dissected aedeagus stored inside the same vial • 1 ♀ adult; TR2 L; 11 Aug. 2019; leg. Freitag; ZMB; both cerci partially broken • 1 ♀ adult; TR2 L; 11 Aug. 2019; leg. Freitag & Pangantihon; NMP; left midleg missing, both cerci partially broken • 1 ♂ adult; TR2 E; 22 Dec. 2018-15 Jan. 2019; leg. Freitag & Pangantihon; AdMU; right midleg broken but stored in the same vial, both cerci partially broken, wings damaged, dissected aedeagus stored inside the same vial. Other Material: Philippines • 1 ♂ larva; HOCg; 16 Jan. 2019; rock surface in riffle, leg. Freitag; AdMU; right hindleg missing, both cerci partially broken • 1 ♀ larva; TIRd; 22 Sept. 2019; leaf pack in riffle; leg. Freitag and Pangantihon; AdMU; both cerci partially broken • 1 ♂ larva; TIRd; 22 Sept. 2019; leaf pack in riffle; leg. Freitag and Pangantihon; CAP-AdMU; segments IX and X including cerci missing • 4 ♀ adults; TR2 E; 19 Nov.-02 Dec. 2018 leg. Freitag; AdMU; some legs missing and all cerci partially broken • 3 ♀ adults; TR2 E; 22 Dec. 2018-15 Jan. 2019; leg. Freitag & Pangantihon; AdMU; some legs missing and all cerci partially broken.

Description.

Imago: Medium-sized species (Fig. 1 ). Forewing length of holotype male: 14 mm, paratype males: 14-18 mm, paratype females: 16-18 mm. General color pale with dark patterns. Ocelli relatively of the same size in both male and female; distance between ocelli more than its diameter in male, less than its diameter in female. Head predominantly pale; dark mottling present posterior of ocelli; with two triangular, dark-brown patches anterior of ocelli and another patch near anterior of head delimiting a pale but distinct M-line. Antenna and palpi slightly darker than head. Pronotum trapezoidal, narrower than head with eyes; anterior edges slightly angled; ground color brown with distinct yellow rugosities and with medial, longitudinal, brown stripe and dark, transverse anterior and posterior lines. Meso- and metanotum pale brownish. Legs yellow; tibia darker than the rest of the legs. Wings hyaline, nearly transparent; veins brown.

Male terminalia (Fig. 2A ): Sterna and terga 2-6 simple. Posterior process of tergum 7 with large, median hump associated with sparsely arranged and long setae, and sensilla basiconica on its hump. Tergum 8 with distinct medial process, strongly curved anteriorly like a hook, bearing dense sensilla basiconica. Tergum 9 simple, with irregular, sparse setation throughout. Posterolateral margin of segments 7-9 with rows of moderately densely arranged, stout, brown setae. Hemitergal lobe covered with fine setae. Hemitergal processes short, not raised in lateral view, slightly bent anteriad subparallel to midline.

Female terminalia. Terga and sterna simple; subgenital plate with slightly bilobed posterior edge of S8, half as wide as segment’s width; inner genitalia (Fig. 2B ) unsclerotized and transparent, with distinct lamellae attached to the receptacle stalk; concentric and lateral folds discernable around and apically of the seminal receptacle’s attachment, respectively.

Aedeagus (Fig. 3A-C ): Aedeagal tube slightly bulky, with dorsobasal and short elongate, ventrobasal sclerites; basoventral surface of tube with hump. Dorsal surface of entire aedeagal tube with wrinkles, but entirely without any spines. Everted aedeagal sac bent slightly ventrad, shorter than aedeagal tube; basolateral lobes with strong apical spines and smaller spinules basally, posterobasal area almost glabrous; mediodorsal lobe slightly raised, fully covered with fine spinules; subapical portion with strong spines, basad increasingly with fine spinules on ventral surface; lateral and dorsal areas around the mediodorsal lobe almost glabrous.

Egg: Color dark brown, oval, nearly spherical, length ca 240 μm, width ca 220 μm, hatching line visible. Chorionic surface regularly punctate throughout, with punctae arranged in polygonal FCIs. Micropyles without any grouped rims near the hatching line (Fig. 4A-D ).

Nymph : General color pale brown, abdomen darker brown (Fig. 5 , larva with identical pattern). Venter pale brown. Female total length 16-18 mm. Male total length 12-13 mm.

Head. Pale, predominantly brownish, slightly wider than pronotum, margins with black outline. M-line pale and tentorial callosities indistinct; stem of ecdysial suture forms a white line which opens in a white spot in the middle of the dark markings anterior of occipital area. Frons simple, with bands of mottlings. Distance in between ocelli slightly greater than their diameter. Antennae longer than combined pro-and mesothorax, yellow. Labium, labial palp, paraglossae, glossae (Fig. 6A ), mandible (Fig. 6B ), maxilla (Fig. 6C ) family-typical. Mandible (Fig. 6B ) with deeply curved molar and five uneven incisors. Maxilla (Fig. 6C ): lacinia scythe blade-like with broad basal half, subapical tooth a third shorter of the apical tooth, four large setae and few smaller setae in the marginal fringe, galea almost as long as lacinia with thin apical seta.

Thorax. Pronotum with yellow middorsal stripe and dark margins. Meso- and meta-notum with yellow mid-dorsal stripe; dark bands extending from mid-length to anterior corners lining borders of wingpads; additional dark markings evident on all thoracic segments. Legs yellow, proportion 1.0:1.3:1.5; proleg: 6.0-6.5 mm, midleg: 7.0-8.0 mm, hindleg: 9.0-10.0 mm long; posterior of all legs entirely lined with very fine, dense setae; setae ca 0.5 mm long. Thoracic gills very dense, length up to 1.0 mm.

Abdomen. Posterior margins of abdominal segments with distinct dark bands. Terga sparsely covered with short, very fine, dark hairs; terga II-X with thin and sharp intercalary setae. Cerci yellow, about half as long as body; cercal hairs short and blunt. Segment X with one pair of anal gills, of approximately 20 filaments in each cluster, ca 0.5 mm long.

Differential diagnosis.

Neoperla mindoroensis sp. nov. imagines are similar to Neoperla nishidai Sivec, 1984 from Greater Palawan in having pointed processes in terga 7 and 8 and in the two large, finger-shaped basolateral lobes at the aedeagal sac. However, N. nishidai has smaller T8 process, and its basolateral lobes and the aedeagal sac are dorsally covered by spines and bare ventrally, while in N. mindoroensis sp. nov. the basolateral lobes are densely armed with spinules, and possess a fully spinulose, slightly raised mediodorsal lobe on the sac. The aedeagal sac of N. nishidai was also described as strongly bent ventrally, while N. mindoroensis sp. nov. is only slightly bent ventrally. Additionally, the egg of N. mindoroensis sp. nov. is significantly smaller (240 × 220 μm) and has less pronounced FCIs than that of the supposedly conspecific female of N. nishidai (340 × 300 μm) ( Sivec 1984). Neoperla PA-9 ( Sivec and Stark 2011: 272, 273), which was claimed to be the putative true female of N. nishidai , also has larger eggs (271 × 256 μm) and an entirely different morphology from N. mindoroensis sp. nov. In addition, Neoperla PA-9 egg has a thin and obscure opercular line, but bearing a series of small, raised spine-like processes, while N. mindoroensis sp. nov. does not have any spine-like structure. The aedeagus of N. palawan Sivec & Stark, 2011 also resembles that of N. mindoroensis sp. nov., but its basolateral lobes are distinctly smaller, rounded, and not elongate, with a low, rounded medioventral lobe. In addition, it does not have a prominent T8 process on the dorsal abdomen. From all other male adult Philippine Neoperla , the new species can easily be distinguished externally by the distinct, complex pattern in its pronotum, structure of its hemitergites, and its genitalia, as described above. The female adult bears the same pronotum pattern.

Etymology.

The toponym refers to the Philippine island of Mindoro, where the type locality is situated.

Distribution.

This species is known so far only from the Baroc River Catchment, Roxas, Oriental Mindoro, Philippines.

Ecology.

In the Baroc River Catchment, the specimens were found in altitudes of 140-530 m a.s.l. from Hinundungan River and Tauga River tributaries (Fig. 7 ). These collection sites were surrounded by either secondary forest or rural extensive farmland, if not secondary vegetation. Along these small to medium-sized (0.4-12 m wide) streams, the nymphs were found on submerged leaf packs, woods, and rock surfaces in riffle sections. In these microhabitats, the following physico-chemical variables were measured or estimated: water current 0.01-0.93 m/s, water temperature 21.5-26.8 °C, pH 7.5-8.5, dissolved oxygen 6.7-8.75 mg/L (mostly, but not always near 100% saturation), biochemical oxygen demand (BOD5) 0.1-1.18 mg/L. The maximum values for dissolved nutrients were 0.5 mg/L phosphate and 1.0 mg/L nitrate.

Figures

Figure 1. Paratype male adult habitus of Neoperla mindoroensis sp. nov. Scale bar: 2.00 mm.

Figure 2. A male terminalia of Neoperla mindoroensis sp. nov. B female inner genitalia. Scale bars: 0.5 mm (A); 0.1 mm (B).

Figure 3. Aedeagus of Neoperla mindoroensis sp. nov. A dorsal B lateral C ventral. Scale bar: 0.1 mm.

Figure 4. SEM micrographs of the egg of Neoperla mindoroensis sp. nov. A full egg B micropyles C chorion surface D hatching line. Scale bars: 20 µm.

Figure 5. Female larval habitus of Neoperla mindoroensis sp. nov. Scale bar: 4.0 mm.

Figure 6. Nymphal mouthparts of Neoperla mindoroensis sp. nov. A labium, ventral B left mandible C left maxilla Scale bars: 0.1 mm.

Figure 7. Type locality and an additional sampling site of Neoperla mindoroensis sp. nov. A HBT B TIR (Photos by Mr. Clister Pangantihon).