Pararhagadochir noronhensis, Costa-Pinto & Olivier & Rafael, 2021

Costa-Pinto, Paula J., Olivier, Renan S. & Rafael, José A., 2021, The first species of Embioptera (Insecta) from the archipelago of Fernando de Noronha (Pernambuco: Brazil), Zootaxa 4941 (1), pp. 142-150 : 143-147

Pararhagadochir noronhensis sp. nov.

( Figs. 2–6 )

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Pararhagadochir sp., Rafael et al. 2020: 16.

Type-series. Holotype Ƌ: Brasil, PE, Fernando de Noronha , Trilha Sancho, 3°51’30’’S – 32°25’50’’W, 20-27.ii.2020, hand-collected, J.A. Rafael, P.C. Grossi, F. Limeira-de-Oliveira . Paratypes: 4 subadult ♀, 1 subadult Ƌ, 28 nymphs, same data as holotype [ INPA] .

Etymology. The specific epithet refers to the type locality: Fernando de Noronha, Pernambuco, Brazil.

Diagnosis. Pararhagadochir noronhensis sp. nov. is closest to P. balteata . The male of P. noronhensis sp. nov. is 4.5 mm long, apterous; with antennal setae of uniform size over the entire length of the antennae; submentum quadrate; epiproct large, triangular, entirely sclerotized, extending the full length of the flap; the female is 7 mm long, and has 17 antennal segments. On the other hand, the male of P. balteata is 11 mm long and alate; with very long antennal setae on the basal half of segments and shorter setae on the apical half; submentum with sides caudally divergent to the basal third; epiproct small, not triangular, partially unsclerotized, not extending the full length of the flap; the female is 14 mm long and has 23 antennal segments.

Description. Male (holotype). Color details (based on specimen in alcohol): predominantly chestnut brown, with the exception of two intersomital white bands on thorax ( Fig. 2A, B ). Body length 4.5 mm. Apterous.

Head subhexagonal, as long as wide, anterior region wider than the posterior region due to the small and slightly protruding eyes, occipital margin uniformly rounded ( Fig. 2C ), length = 0.68 mm, width = 0.70 mm, OR = 0.73; two depigmented areas present, slightly visible ( Fig. 2C ); occipital region with maculae indistinct in dorsal view. Antenna (incomplete) with 11–8 segments ( Figs. 2A, B ). Mm visible, sclerotic, but less pigmented than Sm and well separated; submentum sclerotic, quadrangular, wider than long (2:1), anterior margin straight with the edges rounded ( Fig. 2D ).

Hind basitarsus length = 0.16 mm, width = 0.08 mm; setae rows: 2 inner, 2 proximal, 3 outer; medial bladder present, circular, in the middle of the hind basitarsus, length = 0.02 mm, width = 0.02 mm ( Fig. 4A ). Terminalia . 10L subquadrate, 10R wider basally, tapering distally to form the right process ( Fig. 3A ). 10Rp1 prominent, sclerotic talon. MF narrow and arched ( Fig. 3A ). Outer flange of 10Lp entirely translucent, the inner process curved outward and with same length as the outer flange ( Fig. 3A ); Ep present, visible, in the cleft membrane, seemingly attached at the base of the MF. H sclerotic; Hp well developed, central, right curved, with many transverse lines on its anterior margin ( Fig. 3B ); Lpp present, sclerotic ( Fig. 3B ); LC1dp well developed, quadrate, echinulate. Length of the left cercus: LC1 = 0.27 mm, LC2 = 0.29 mm; width of the left cercus: LC1 = 0.09 mm, LC2 = 0.07 mm; length ratio of LC1/LC2 = 0.93.

Female subadult (Paratype). Color details (based on specimens in alcohol): same color pattern as male, but lighter ( Fig. 5A ). Body length 7 mm.

Head circular, as long as wide ( Fig. 5C ), length = 0.85 mm, width = 0.85 mm; eyes small, not protruding, OR = 0.88; three depigmented areas present, sometimes the central one barely discernible ( Fig. 5C ); occipital region with four pairs of maculae visible in dorsal view, two larger lateral maculae reaching half of the head length, median macula smaller, and one contiguous central cordiform macula ( Fig. 5C ); two more pairs of maculae visible in ventral view ( Fig. 5D ). Antennae with 17–17 segments ( Figs. 5A, B ). Mm and Sm slightly sclerotic; Sm quadrangular, wider than long (1.6:1) ( Fig. 5D ).

Hind basitarsus slightly more robust than male, length = 0.19 mm, width = 0.10 mm; setal rows: 1 inner, 2 proximal, 3 outer; medial bladder present, ellipsoid, same position as in male, length = 0.07 mm, width = 0.04 mm ( Fig. 4B ). Terminalia with 1st valvula slightly differentiated from the 8th sternum; 8th sternum with posterior margin uniformly rounded ( Figs. 6A, B ).

Distribution. Brazil: Pernambuco, archipelago of Fernando de Noronha ( Fig. 1 ).

Types condition. Holotype: Good, lacking right hind leg; both antennae missing their distal halves ( Figs. 2A, B ). The four female paratype specimens apparently subadult (5th instar) based on morphological characteristics as some depigmented areas appear reabsorbed such as in the paraproct.

Intraspecific variation. Female paratypes exhibit lighter or darker shades of chestnut brown color, though never so dark as male.

Biology. The holotype male of P. noronhensis sp. nov. is apterous, an unusual characteristic for male webspinners. The reduction or absence of wings is probably induced by the secretion of the juvenile hormone, which is one of the factors responsible for the neotenization ( Iwanaga & Tojo 1986; Ross 2000). The amount and timing of secretion of juvenile hormone during nymphal instars influences directly the development of male wings: complete, when macropterous; partial, when subapterous or micropterous; or none, when apterous. All of these conditions can occur within the same species population. In arid environments, apterous males tend to remain inside the colony, mate with sisters, and consequently increase the probability of new males also being apterous. On the other hand, macropterous males living in more favorable environments can fly from colony to colony and perform random matings, thus decreasing the tendency to apterism ( Ross 2000). For Pararhagadochir the trend towards apterism has been observed at the population level in P. trachelia Navás, 1915 ( Szumik 2004) .

Figures

FIGURE 1. Geographical occurrence of Pararhagadochir Davis, 1940 species in Brazil.

FIGURE 2. Holotype male of Pararhagadochir noronhensis sp. nov. A. Habitus, dorsal view; B. Habitus, ventral view; C. Head, dorsal view (arrows indicate two depigmented areas outlined in white); D. Head, ventral view (Mm and Sm outlined in white). Scales: A–B = 3 mm, C–D = 0.5 mm.

FIGURE 3. Holotype male of Pararhagadochir noronhensis sp. nov. A. Terminalia, dorsal view and next to it the same structure expanded for more details; B. Male terminalia, dorsal (left) and ventral view (right); C. Specimen labels. Scales: A–B = 0.5 mm.

FIGURE 4. Hind basitarsus of Pararhagadochir noronhensis sp. nov. in ventral view exhibiting the middle bladders. A. Holotype male; B. Paratype female. Scale = 0.5 mm.

FIGURE 5. Paratype female of Pararhagadochir noronhensis sp. nov. A. Habitus, dorsal view; B. Habitus, ventral view; C. Head, dorsal view (arrows indicate two depigmented areas); D. Head, ventral view. Scales: A–B = 4 mm, C–D = 0.5 mm.

FIGURE 6. Paratype female of Pararhagadochir noronhensis sp. nov. A. Terminalia, ventral view and next to it the same structure expanded for more details; B. Female terminalia, dorsal (left) and ventral view (right); C. Specimen labels. Scales = 0.5 mm.