Ctenarytaina elinae, Percy, 2025

Ctenarytaina elinae sp. nov.

( Figs 1 View FIGURE 1 , 2 View FIGURE 2 )

Adult colour and structure. General colour dark brown-black with dark red markings on head and thorax; forewing membrane ochreous with veins brown. Head wider than thorax, deflexed downwards approximately 50–60° from longitudinal axis of body ( Figs 1I, 1N View FIGURE 1 ), vertex with distinct preocular tubercule ( Fig. 1G View FIGURE 1 ), genal processes well developed, moderately long (length approximately 0.5 times vertex length), broad and bluntly rounded ( Figs 1G, 1H View FIGURE 1 ). Distal proboscis segment short ( Fig. 1F View FIGURE 1 ). Antenna 10-segmented, shorter than head width (length 0.8–0.9 times head width), segment 3 longest, and segments 4, 6, and 8 subequal in length, a single subapical rhinarium on each of segments 4, 6, 8, and 9, terminal seta longer than either segment 9 or 10 ( Figs 1H, 1O View FIGURE 1 ). Thorax well arched ( Fig. 1N View FIGURE 1 ). Mesotibia with a subapical comb of bristles (as typical for the genus). Hind leg coxae with small, globular meracanthus ( Fig. 1J View FIGURE 1 ); metatibia length 0.5-0.6 times head width, longer than metafemur ( Fig. 1J View FIGURE 1 ); metatibia without basal genual spine but with a stout basal seta ( Fig. 1L View FIGURE 1 ), with 6 more or less grouped apical spurs; metatarsi subequal in length; proximal metatarsus with two lateral spurs ( Fig. 1K View FIGURE 1 ). Forewing length 2.1–2.4 times head width, widest basally, narrowing in apical half to a narrowly rounded apex ( Figs 1A, 1B View FIGURE 1 ); costal break and pterostigma developed; veins thicker basally than apically ( Figs 1A, 1B View FIGURE 1 ) and incomplete vein development introducing a break at the junctures of veins M and Cu 1a with vein Cu 1 ( Fig. 1D View FIGURE 1 ); vein Rs length approximately 0.8 times wing length, almost straight, medially weakly curved towards fore margin, vein M much longer than its branches, cell cu 1 long and low, vein Cu 1a almost straight to slightly sinuous, medially weakly curved towards hind margin, vein apex reaching the margin distal to bifurcation of vein M ( Figs 1A, 1B View FIGURE 1 ); membrane with surface spinules (forming linear patterns more basally or cellular patterns more apically) present in all cells. Hindwing broad, length 0.8–0.9 times forewing length, costal margin sinuate, venation prominent, apex more broadly rounded than forewing apex ( Fig. 1C View FIGURE 1 ). Abdomen with pore fields present on intersegmental membrane ( Figs 2M, 2N View FIGURE 2 ). Male terminalia (aedeagus missing) as in Figs 2A, 2B View FIGURE 2 ; proctiger two-segmented, length approximately 0.6 times head width, with basal segment of proctiger in lateral view more or less parallel sided, weakly produced posteriorly, apical segment short, tubular, length approximately 0.2 times length of basal segment; subgenital plate, in lateral view with dorsal margin concave ( Fig. 2B View FIGURE 2 ); paramere, in lateral view, digitiform, more or less parallel sided, weakly curving anteriorly, exterior surface with short simple setae, interior surface with stout simple and peg setae ( Figs 2C, 2D View FIGURE 2 ). Aedeagus missing (lost during slide mounting) but noted as similar to that illustrated for C. longicauda Taylor, 1987 ( Fig. 2E View FIGURE 2 ) with distal portion short and apex bulbous. Female terminalia elongate, massive with respect to body length, extending beyond wing apex ( Figs 1N View FIGURE 1 , 2I View FIGURE 2 ), with 3 discrete areas of dense sclerosis ( Fig. 2O View FIGURE 2 ); proctiger length more than 1.2 times head width and more than 3 times anal ring length ( Figs 2I, 2K View FIGURE 2 ); proctiger in lateral view, with apical portion post anal ring convex with shallow subapical depression ( Fig. 2I View FIGURE 2 ); proctiger in dorsal view, with basal portion more or less parallel sided, gradually narrowing to acute apex, with 5–9 (at broadest section) longitudinal rows of stout peg setae near ventral margin ( Fig. 2K View FIGURE 2 ); anal ring narrowly elongate oval and composed of a double row of cells ( Fig. 2J View FIGURE 2 ); subgenital plate length approximately 0.8 times proctiger length, basal portion in ventral view more or less parallel sided, apical portion gradually narrowing to acute apex ( Fig. 2L View FIGURE 2 ). Ovipositor with dorsal valvulae small (length less than half anal ring length), low and curved ( Fig. 2P View FIGURE 2 ).

Adult measurements (mm) and ratios. ( 1 male, 3 females). WL: 1.62–2.31; WW: 0.67–0.93; HW: 0.76– 0.93; AL: 0.68–0.84; PB: 0.08–0.09; WL:WW: 2.42–2.59; WL:RsL: 1.26–1.29; CUR: 2.63–3.35; MR: 0.33–0.4; HM:HCU: 2.07–2.41; HW:VW: 1.58–1.70; VL:VW: 0.43–0.48; VL:GC: 1.92–2.30; WL:HW: 2.13–2.37; AL:HW: 0.84–0.89; HW:HT: 1.80–1.86; HT:HF: 1.22–1.34. Male terminalia: MP: 0.45; PL: 0.26; AEL: missing; PL:HW: 0.34; MP:PL: 1.73; PL:SH: 1.30. Female terminalia: FP: 1.11–1.19; FSP: 0.90–1.00; RL: 0.31–0.38; OVH: 0.02– 0.03; EL: 0.24; EW: 0.09; FP:RL: 3.13–3.58; FP:HW: 1.23–1.25; FP:SP: 1.19–1.23; EL:EW: 2.67.

Immature. Unknown.

Egg. Broadly ovoid, apparently smooth, without surface sculpturing or patterning, with a short basal pedicel and a very short tail ( Fig. 2Q View FIGURE 2 ).

Host plant and biology. The host plant is unrecorded, it may be Metrosideros ( Myrtaceae ) (see Discussion). No biological information is available, but the immatures are likely to be free-living as is typical for the genus ( Burckhardt et al. 2020).

Note. The aedeagus of the single male specimen and holotype was lost during slide mounting, but the structure of the aedeagus and shape of the distal segment apex had already been noted as similar to that of C. longicauda (illustrated in Fig. 2E View FIGURE 2 ). Ctenarytaina lulla ( Tuthill, 1942) is the only other Ctenarytaina known from the Society Islands, and the original description of C. lulla by Tuthill (1942), which I use for my comparison with C. elinae , was based on just two females (material not examined) and no further records are known. Moreover, when Tuthill (1952) transferred the species to Ctenarytaina (from Papiana Tuthill, 1942 ) he provided no further description.

Comments and Systematics. Burckhardt et al.(2020) noted that extra pore fields on the abdominal intersegmental membrane are present in females only in some species (e.g., Ctenarytaina insularis Martoni & Armstrong, 2019 ); in C. elinae these pores are found in both male and female ( Figs 2M, 2N View FIGURE 2 ). Martoni & Armstrong (2019) clearly considered the Pacific taxa, C. distincta ( Tuthill, 1943) , C. lulla and C. remota Tuthill, 1956 to be related to the native Australian taxon, C. insularis . Burckhardt et al. (2020) additionally included C. longicauda and three other taxa ( C. baliola Burckhardt, 2020 , C. bipartita Burckhardt, Farnier, Queiroz, Taylor & Steinbauer, 2013 , C. cubicella ( Kandasamy, 1986)) together in a larger related group primarily based on the structure of the female terminalia that is somewhat inflated basally and strongly narrowed medially to a narrow apical process. However, this description does not fit the structure of C. longicauda or C. elinae , and therefore I consider these two latter species to represent a separate species group. I also interpret the presence of two species groups as evidence for at least two separate colonizations across the Pacific and specifically to French Polynesia. There is, nevertheless, evidence that these two species groups are related within Ctenarytaina . Ctenarytaina elinae sp. nov. was included in the mitogenome analysis of Percy et al. (2018) (as “DP1.idba.269_ Aphalaridae _ Ctenarytaina _sp”), where it groups with strong support (100% bootstrap) with an undescribed species (as “DP1.ctg022_circ_ Aphalaridae _ Ctenarytaina _sp”) from New Caledonia close to C. insularis , albeit with reasonably deep divergence between them ( Percy et al. 2018), and based on the COI fragment the divergence is 16.5%. Only four Ctenarytaina species were included in Percy et al. (2018), but the results suggest that although the Ctenarytaina diversity in French Polynesia likely derived from at least two separate colonizations from Australasian origins, the two different species groups ( C. elinae versus C. lulla and C. remota ) are likely related groups within the genus. The closest relative to Ctenarytaina elinae sp. nov. (based on morphology, and combined COI and cytB data) appears to be C. longicauda which is native to Australia (but introduced in several regions; Burckhardt et al. 2020). The relationship between these species is suggested by the extremely elongate and massive female terminalia ( Figs 1M, 1N View FIGURE 1 and Figs 2H, 2I View FIGURE 2 ), which also readily differentiates C. elinae from other known Pacific Ctenarytaina taxa. Ctenarytaina elinae is a larger species than C. longicauda ( Figs 1M, 1N View FIGURE 1 ), the forewing of C. longicauda , although similar in shape to C. elinae , is less broad basally ( Fig. 1E View FIGURE 1 ), the veins do not become thickened in the basal portion of the forewing, cell cu 1 is wider (CUR> 3.5) and cell m 1 is lower (MR> 0.4); the male terminalia structure is also similar between the two species, with similar structure of proctiger, subgenital plate and aedeagus (see note above) ( Fig. 2E View FIGURE 2 ), but the paramere is more slender in C. longicauda ( Figs 2F, 2G View FIGURE 2 ). The similarities in the general structure of the female terminalia also include the presence of three discrete areas of dense sclerosis (two in the proctiger, one in the subgenital plate, Fig. 2O View FIGURE 2 ), and these were illustrated for C. longicauda by Taylor (1987); the area of sclerosis post anal ring on the proctiger is more prominent in C. longicauda and is sometimes marked in this taxon by darker pigmentation ( Fig. 2H View FIGURE 2 ). The function of these sclerotized areas is not clear, but they may provide structural reinforcement supporting the relatively massive terminalia. Similarly, the distinctive depression on the dorsal surface of the proctiger towards the apex is more pronounced in C. longicauda ( Figs 2H, 2I View FIGURE 2 ). Despite these shared morphological characters, DNA barcodes indicate that C. elinae and C. longicauda species are considerably genetically divergent (17.8% COI divergence). No DNA data is available for the other Pacific Ctenarytaina .

Genetic resources. Genbank: MG988720 View Materials ( COI), MG989020 View Materials (cytB) .

Distribution. Only recorded from a single locality at high elevation on the island of Tahiti, Society Islands, French Polynesia.

Type material. Holotype male (slide mounted), Orohena trail to summit of Pito Hiti , Tahiti Nui, Society Islands, French Polynesia, 2000–2110 m, 1 st –2 nd June 2006, coll. EC8906, E. Claridge leg. ( NHMUK) . Paratypes 3 females (slide mounted), as for holotype ( NHMUK and DMPC) .

Etymology. Named for the entomologist, Elin Claridge, who collected the only known specimens.