Cyclopoliarus nigelwatsoni Bahder, Bartlett & Hendrix, 2025

Cyclopoliarus nigelwatsoni Bahder, Bartlett & Hendrix sp. nov.

( Figures 3-8 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Type locality. Caño Negro , Alajuela Province, Costa Rica.

Diagnosis. Yellow-orange body coloration with three distinct longitudinal stripes on mesonotum. Vertex fuscous, face predominately pale. Pygofer (lateral view) bilaterally asymmetrical, left side bearing large truncate lobe on lateral margin of pygofer opening. Aedeagus with elongated, apical process curved retrorsely to reach base of aedeagus and complex of three processes arising near aedeagal midlength on left side in ventral view.

Description. Color. Ground color yellow-orange ( Fig. 3 View FIGURE 3 ). Vertex dark fuscous, carinae pale. Frons yellow-orange except two dark fuscous patches at dorsal margin (either side of median carina) and pair of light fuscous patches adjacent to median ocellus; anteclypeus and labrum pale medially, dark laterally. Mesonotum bearing three longitudinal fuscous stripes (one at midline with two circular projections at anterior margin, and two laterad of lateral carinae). Abdomen with middorsal fuscous wash on middle segments.

Structure. Body length males (n = 4): 9.1–9.3 mm with wings; 5.3–5.6 mm without wings ( Table 4 View TABLE 4 ). Head. In dorsal view, vertex narrow ( Fig. 4A View FIGURE 4 ), about 2.25 times as long as wide, slightly constricted medially, wider at anterior and posterior margins, lateral carinae foliate (disc deeply concave), anterior margin slightly convex, bearing transverse apical carina, posterior margin strongly and broadly concave (with median notch), subapical transverse carinae originating from anterior margin of eye to meet subapically, connecting to apical transverse carina by pair of parallel ridges defining small areolet (visible from dorsoanterior view); lateral areolets subtriangular, reaching anterior margin of eyes; in lateral view ( Fig. 4B View FIGURE 4 ), head in profile generally rounded (vertex convex, face more linear than vertex) with slight keel at fastigium (at apical transverse carina), head anteriorly projecting for distance about equal to width of antennae; in frontal view ( Fig. 4C View FIGURE 4 ), face roughly rhomboid (strongly concave at dorsal margin), lateral carinae foliate; frons narrowest at dorsal margin, expanding approximately to level of antennae, then converging; lateroventral portion of each side bearing distinct fovae; median carina distinct, forked between eyes to form indistinct areolet. Frontoclypeal suture strongly curved to define large median quadrate region. Ocelli distinct, lateral ocelli at anterovetral margin of eye. Eyes rounded, emarginated above antenna. Antennae short, scape ring-like, pedicel bulbous (a little taller than wide), flagellum setaceous with bulbous base.

Thorax. Pronotum very short ( Fig. 4A View FIGURE 4 ); anterior margin bluntly convex, posterior margin broadly angulately incised, strongly carinate with lateral carinae extending from midline, foliate, arched laterally (following outline of head margin), extending laterally on to paradiscal region ( Fig. 4B View FIGURE 4 ), reaching anterior margin of paradiscal region about level of antenna; paradiscal region broad, irregularly quadrate, ventral margin exceeding antennae. Mesonotum longer than broad bearing five carinae, intermediate carinae obscure, lateral carinae complete to posterior margin, median carina obsolete on scutellum. Hind leg with three lateral teeth, apical ornamentation 6-7/8-8.

Forewing transparent ( Fig. 5 View FIGURE 5 ), light amber, veins dark and distinct, setae-bearing tubercles inconspicuous; oblong, costal margin gently curved, apex rounded, posterior margin nearly linear, RA 2-branched, RP 3-branched, M 5-branched and CuA 2-branched.

Terminalia. Pygofer in left lateral view ( Fig. 6A View FIGURE 6 ) narrowest dorsally, anterior margin concave and irregularly sinuate, posterior margin bearing large truncate projection on lateral margins of pygofer opening; in ventral view; medioventral process subtriangular (taller than wide), about a third as tall as lateral margins. Gonostyli elongated; in lateral view ( Fig. 6A View FIGURE 6 ) proximally narrow, distally broadly expanded into broad upturned subquadrate region; distal apex rounded; in ventral view, slender basally, distally expanded laterally and cephalad from midpoint, then tapered to broadly rounded apex. Aedeagal complex with periandrium narrow, enclosing most of aedeagal shaft, bearing an elongated curved apical process (A1, apex reaching base of aedeagus) and a cluster of processes (A2a–e) arising from same base near midlength of aedeagus (on left, ventral view, Figs. 7B View FIGURE 7 , 8B View FIGURE 8 ). The endosoma is curved left (ventral view, Figs 7B View FIGURE 7 , 8B View FIGURE 8 ), and again near midlength, expanded subapically into irregular lobe, bearing a short, slender curved process (E1, Figs. 7B View FIGURE 7 , 8A, B View FIGURE 8 ). Anal segment in dorsal view asymmetrical ( Fig. 6C View FIGURE 6 ), elongated, apex pointed (apex to right of center from dorsal view); from lateral view, ventral margin nearly linear, apex pointed, projected caudad.

Plant associations. Elaeis oleifera (Kunth) Cortés (American oil palm).

Distribution. Northern Costa Rica, Caño Negro.

Etymology. The specific name is a patronym for Mr. Nigel Watson, a close friend of the senior author whose friendship during his undergraduate years was instrumental to his success.

Material examined. Holotype male “ Costa Rica, Alajuela Pr. / Caño Negro / 19.V.2019 / Coll.: B.W.Bahder // Holotype / Cyclopoliarus nigelwatsoni ♂ ” ( FLREC) ; Paratypes 2 males, 5 females, same data as holotype ( FSCA) .

Sequence Data. For the barcoding region of COI, a 529 bp product was generated, for 18S, a 1,367 bp product was generated and for the D9–D10 expansion region, a 771 bp product was generated. In all analyses, the Pentastirini were monophyletic and closely related to the Oecleini. Within the Pentastirini , Cyclopoliarus nigelwatsoni sp. nov. was derived from within the genus Melanoliarus . For both 18S and 28S ( Fig. 9A, 9B View FIGURE 9 ) there is strong bootstrap support (100) for the placement of C. nigelwatsoni sp. nov. adjacent to Melanoliarus , and also in the concatenated data consensus tree ( Fig. 9D View FIGURE 9 ) based on COI, 18S and 28S ( Fig. 9 View FIGURE 9 ) with strong bootstrap support (98). However, the relationship of C. nigelwatsoni sp. nov. to congeners and Melanoliarus cannot be properly assessed because there is no molecular data for other species of Cyclopoliarus . Melanoliarus is a large (~80 species), heterogeneous taxon and this result may be reflective of paraphyly in Melanoliarus . Also, the outgroup taxa are members of different tribes (Oecleini and Bothriocerini), that may prove to not be closely related to the Pentastirini .A recent phylogenetic study ( Luo et al. 2024) shows Bothriocerini arising within a paraphyletic Oecleini, resolving adjacent to Oecleus and most closely related to the Pentastrini. This relationship is generally confirmed by our analysis but non Oecleini/ Borthiocerini/Pentastrini taxa were not analyzed in this study so this larger scale relationship was not tested here. While this relationship is likely accurate, a critical issue is that Oecleini, as currently defined, is paraphyletic and, thus, the tribal classification needs revision. The data herein suggests that there is at least one (maybe two) lineages within the Oecleini that merit tribal status. In one scenario, Myxia + Haplaxius + Nymphocixia (this study but including Coframalaxius and Trigonocranus when considering Luo et al. 2024). In the other Myxia (with Meenocixius and Borbonomyndus from Luo et al. 2024) forms a distinct tribe relative to Haplxius + Nymphocixia ( Coframalaxius + T rigonocranus from Luo et al. 2024), which forms a separate tribe. These changes to the classification are beyond the scope of this study and will require further analysis with denser taxon sampling and, likely, additional molecular markers to resolve/confirm. Among the taxa analyzed, the pairwise comparison based on 18S, C. nigelwatsoni sp. nov. differs from the subset of species for Melanoliarus at a level consistent with intrageneric variability (an average of 0.5% different) and differs from other genera in the Oecleini and Bothriocerini by an average of 3.2%. Furthermore, intrageneric variability with the Oecleini and Bothriocerini is on average 0.5% and 0.6%, respectively ( Table 5 View TABLE 5 ).

Remarks. Placement of Cyclopoliarus nigelwatsoni sp. nov. in this genus is supported by the general habitus, large size and features of the terminalia, including the asymmetrically pointed anal tube. The general features of the terminalia are similar to other members of the genus (e.g., Fennah 1945a, figs. 27–36; Fennah 1945b, plate XI; Fennah 1971, figs. 99–105). The only other member of Cyclopoliarus that has been described from the mainland is C. omani ( Metcalf, 1938) , from Panama ( Fig. 10 View FIGURE 10 ). The general color pattern of the body of C. omani is very similar to C. nigelwatsoni sp. nov., differing in several details (most notably, the face of C. omani is more extensively marked with fuscous). These taxa are also diagnosable by male terminalia. Regarding the terminalia, the pygofer of C. omani is closer to symmetrical ( Figs. 10B, C View FIGURE 10 ), the medioventral process of the pygofer is shorter and pentagonal in C. omani (triangular and longer in C. nigelwatsoni sp. nov.), and the anal tube is more strongly asymmetrical and pointed in C. nigelwatsoni sp. n ov. ( Fig. 6C View FIGURE 6 ), whereas it is weakly asymmetrical and apically bilobed in C. omani . The aedeagus and periandrium of the two species are similar in overall structure, but differ in the position and arrangement of nearly all associated processes; including the prominent apical process ( Figure 8 View FIGURE 8 , A 1 View FIGURE 1 ) is absent in C. omani , and the cluster of processes ( Fig. 8 View FIGURE 8 , A 3a–d View FIGURE 3 ) arises more distad in C. omani and is differently organized; C. omani possesses a prominent elongated and sinuate process on (from ventral view) the left lateral side (the dextral process of Mead & Kramer 1982), elongated processes on the dorsal midlength of the endosoma (both absent in C. nigelwatsoni sp. nov.), and two similar slender processes on the apex of the endosoma.

Other type material examined. Holotype Oliarus omani Metcalf 1938 ( USNM, male, Fig. 10 View FIGURE 10 ) “TrinidadRiv / Pan Mar 2.11 / AugustBusck // Oliarus omani / Det. Z.P.M. Met. / Holotype [red paper] / USNMENT 01145683 [2D barcode label]” Paratype (2 males, USNM), same data as holotype, 2D barcodes AMNH _ IZC 00300536 About AMNH , UDCC _ TCN 00101741 View Materials .

Other material examined (male, USNM), same data as holotype (no paratype label), 2D barcode UDCC _ TCN 00101754 View Materials .