Oecleus dormido Bahder & Bartlett, 2022

Barrantes Barrantes, Edwin A., Zumbado Echavarria, Marco A., Bartlett, Charles R., Helmick, Ericka E. & Bahder, Brian W., 2022, A new species of Oecleus (Hemiptera: Auchenorrhyncha: Fulgoroidea: Cixiidae) from the Caribbean coast of Costa Rica and a reassessment of the generic status of Nymphomyndus, Zootaxa 5133 (4), pp. 509-526 : 513-519

Oecleus dormido Bahder & Bartlett sp. n.

( Figures 2–6 )

Type locality. Tortuguero , Limón Province, Costa Rica

Diagnosis. Moderate sized (~ 6 mm) species with five carinae on the mesonotum and head slightly projecting beyond the eyes with a golden-brown coloration. Forewing vein CuA forked close to claval margin, anastomosing to form a small closed C5 (‘procubital cell’). Male terminalia with elongate pygofer bearing a broad, rounded medioventral process situated between a pair of upturned rounded lobes, endosoma strongly contorted, forming distinct helix, with two processes (one exceeding endosomal apex), aedeagus with two long, slender processes and endosoma with two long, slender processes (in ventral view, right process nearly straight, much longer than left). Anal tube, in lateral view convex ventrally forming large, quadrangular lobes.

Description. Color. General body color in males pale orange-brown, darkly infuscated in concavities ( Fig. 2 ). Frons and genae dark brown, clypeus dark brown below antennae, otherwise paler; lateral ocelli reddish. Metanotum with carinae of mesonotum stramineous, region between lateral and intermediate carinae strongly infuscate. Structure. Body length males (n = 4): 6.02–6.05 mm with wings; 4.22–4.25 mm without wings ( Table 3 ). Head. Anterior margin (lateral view, Fig. 2A ) of head rounded (with slight keel on fastigium corresponding in transverse carina), head weakly projected in front of eyes, vertex and face (below fastigium) weakly convex. Vertex very narrow ( Figs 2B , 3C , median carina absent), broadest at fastigium, narrowed posteriorly, lateral keels foliate, nearly in contact at posterior margin. Frons in frontal view ( Fig. 3A ) foliately keeled on lateral margins, median carina distinct, becoming obsolete near fastigium, dorsal margin “V-shaped”, lateral margins sinuate, narrowest between eyes, distinctly expanding at level of antennae, widest just above frontoclypeal suture; median ocellus distinct just above frontoclypeal suture; frontoclypeal suture approximately straight, clypeus triangular with distinct median carina. Antennae bulbous with scape ring-like and very short ( Figs. 3A, B ), pedicle rounded (as wide as tall) bearing many sensory plaques, flagellum elongate, bristle-like with bulbous base. Lateral ocelli distinct below compound eye, anterior to antenna.

Thorax. Pronotum short in dorsal view ( Fig 2B , 3C ), anterior margin hidden by head, posterior margin concave; disc with median carina near obsolete laterally flanked with serpentine oblique carinae, lateral margins with carinae between tegula and eye; in lateral view ( Fig. 3B ), paradiscal region broad forming rough parallelogram between ventral margin and lateral carina. Mesonotum longer at midlength then vertex plus pronotum combined ( Fig. 3C ), disc bearing five carinae, lateral and intermediate carinae subparallel, slightly sinuate.

Wings transparent ( Fig. 4 ), inconspicuous setae-bearing pustules along veins, forewings with a distinct stigma. Forewings elongate with leading and trailing sides approximately parallel-sided (leading margin weakly arched); apex of clavus past forewing midlength, Pcu+A1 fused before midlength of clavus (at about 1/4 forewing length), composite vein reaching wing margin well before CuP, combined vein stem ScP+R+MP forming long stem from basal cell, fork of MP from ScP+R at level with fusion of Pcu+A 1; fork of RP from ScP+RA near wing midlength; CuA forked close to claval margin distal. Branching pattern: RA 1-branched, RP 4-branched, MP 5-branched; CuA 2-branched (distally anastamosed in CuA 1 +CuA 2 forming small closed ‘procubital cell’ [i.e., Emeljanov 1996]); crossveins ir, r-m, im, m-cu and icu present ( Fig. 4 ).

Terminalia. Terminalia approximately bilaterally symmetrical. Pygofer in lateral view broad ( Fig. 5A ), narrowest and roundly projected at dorsal margin, greatly expanded ventrally, ventral margin irregularly sinuate, with strong invagination just prior to medioventral process, posterior margin convex, anterior margin concave, irregularly sinuate. In ventral view ( Fig 5B ), medioventral process rounded, slightly longer than wide, attached to a trapezoidal base bearing lateral rounded lobes, appearing “crown-like”. Gonostyli in lateral view ( Fig 5A ) slender, expanded in distal half, dorsal margin bearing triangular projection, apex rounded; in ventral view ( Fig. 5B ), margins subparallel, curving mesad, forming subtriangular apices, inner margins hooked subapically, curving basad. Aedeagus slender ( Fig. 6 ), two slender subapical retrorse processes (A1 & A2) on lateral margins, right lateral process (A1) elongate, nearly reaching base, slightly curved distad, left lateral process (A2) approximately half the length of A1, curved distad. Endosoma complex, with two large processes (E1 & E2); E1 arising on dorsal margin, angled dorsad, nearly reaching apex of flagellum, E2 arising subapically on left lateral margin, curved ventrad, nearly reaching base of aedeagus, flagellum strongly helical, completing 1.75 rotations around axis from base to apex ( Fig. 6D ). Anal segment in lateral view ( Fig. 5A ) expanded distally and strongly downcurved (forming pair of quadrangular lateral flanges), basis narrow. In dorsal view ( Fig. 5C ), tear-drop shaped, narrowed distally; paraproct lingulate.

Plant associations. Unknown; collected sweeping edge habitat, predominantly grasses.

Distribution. Tortuguero, Limón Province, Costa Rica.

Etymology. The specific epithet is the Spanish slang for sleepy.

Material examined. Holotype male “ Costa Rica, Limón Pr. / Tortuguero / 13.V.2018 / Coll.: M.A. Echavarria // Holotype / Oecleus dormido ♂ ” ( FLREC) ; Paratypes 2 males, 2 females, same data as holotype ( FSCA) .

Sequence data. For the COI locus, a 545 bp product was generated (GenBank Accession No. OM 264283 ), for the 18S locus, a 1,349 bp product was generated (GenBank Accession No. OM 258693 ), and for the H3 locus, a 280 bp product was generated (GenBank Accession No. OM 262392 ). Based on the phylogenetic analyses of the COI, 18S, and H3 loci and the consensus analysis ( Fig. 7D ), Oecleus dormido sp. n. resolves adjacent to O. borealis ( Fig. 8 ). Based on the consensus tree, Oecleus (assessing the three taxa available here) is monophyletic with strong bootstrap support (95). This is also seen in the 18S phylogeny (94 bootstrap support) ( Fig. 7B ). There is weak bootstrap support for this based on H3 (18, Fig. 7C ) and Oecleus is not monophyletic based on COI ( Fig. 7A ). In all analyses except for H3 (which is based on 280 bp), the genera Nymphomyndus and Nymphocixia are sister groups. The strong phylogenetic bootstrap support (99) for these two genera as a clade.

Based on the pairwise comparison of the 18S gene for taxa assessed, the average variability within genus is 0.4% (±0.1), 0.6% (±0.3), 0.7% (±0.2) for Oecleus , Myxia , and Haplaxius respectively ( Table 4 ), while the variability among genera is an average of 2.2% (±0.04). Oecleus dormido sp. n. differs from O. borealis and O. mackaspringi by 0.2% and 0.5%, respectively. The difference between Nymphomyndus and Nymphocixia is 0.98% at the 18S locus

Remarks Oecleus dormido sp. n. is placed in Oecleus based on both morphological (lacking spines on hind tibia, trough-like vertex, head slightly projecting, and five longitudinal carinae on mesonotum) and molecular features based on analysis of three independent loci (see below).

In Kramer’s (1977) key to US species (treating 40 species north of Mexico), Oecleus dormido sp. n. appears to trace to couplet 28–29 (viz. O. jenniferae Kramer , O. excavatus Ball , O. palton Kramer ) based on the following features used in the key: aedeagal shaft with 2 processes (shaft without acute projection near midlength or base), aedeagal shaft without expansion on dorsal margin, anal tube not triangular (anal tube in lateral view ventrally strongly convex and lobed); endosoma with 2 processes (proximal process [E1] not strongly recurved [viz. couplet 16] or minute [viz. couplet 26]), right aedeagal process [A1] in lateral view more than half length of shaft, not strongly bowed and protruding beyond flagellum. Of these species Oecleus dormido sp. n. has terminalia most similar to O. jenniferae but has only one (not both) flagellar processes shorter than the flagellum, and the shape of the medioventral process of the pygofer is different (rounded, slightly longer than wide in O. dormido sp. n., versus ovately produced from subtriangular base, Kramer 1977, fig. 91). Oecleus dormido sp. n. differs from both O. excavatus and O. palton in having one of the endosomal processes shorter than the endosoma (vs. both longer) and the shape of the medioventral process (more elongate in both O. excavatus and O. palton ), and also the shape of the anal tube (see Kramer 1977, figs 85–87 and 94–96). Oecleus dormido sp. n. appears unique among its congeners by have a strongly helical endosoma.

Aside from species treated in Kramer (1977), 18 species of Oecleus were described or redescribed (with terminalia illustrated) by Caldwell (1944), O’Brien (1982), Emeljanov (2007), Bartlett et al. (2018), and Myrie et al. (2019) all of which differ from Oecleus dormido sp. n. based on male terminalia (especially the shape of the anal tube and the medioventral pygofer process). Of the remaining eight species, seven from Mexico are treated by Fowler (1904, table 10, figs. 3–13) and differ from the new species in coloration and or shape of the head (although Kramer 1977: 379–380 notes that Oecleus decens Stål is an ‘unrecognizable species’ based on ‘ one female from an unspecified locality in Mexico’), and finally, Oecleus monilipennis Van Duzee (from ‘Ceralbo Island’, now Isla Jacques Cousteau, in the Gulf of California) as described by Van Duzee (1923: 190–191) as close to Oecleus fulvidorsum Ball (see Kramer 1977, figs 28–30), except with a ‘subtriangular’ medioventral process of the pygofer and the anal tube ‘scarcely surpassing’ the gonostyli. From these observations, we conclude that that Oecleus dormido sp. n. is an undescribed species.

Figures

FIGURE 2. Adult male habitus of Oecleus dormido sp. n.; (A) lateral view and (B) dorsal view, scale = 1 mm.

FIGURE 3. Adult Oecleus dormido sp. n. (A) head and pronotum frontal view, (B) head, pronotum, and mesonotum lateral view, and (C) head, pronotum, and mesonotum dorsal view; scale = 1 mm.

FIGURE 4. Forewing venation of Oecleus dormido sp. n.; black = vein, italics = crossvein, green = cell.

FIGURE 5. Male Oecleus dormido sp. n. terminalia; (A) lateral view, (B) ventral view, and (C) dorsal view.

FIGURE 6. Aedeagus of Oecleus dormido sp. n.; (A) left lateral view, (B) right lateral view, (C) ventral view, and (D) dorsal view.

FIGURE 7. Maximum likelihood phylogenetic tree based on 1,000 replicates: (A) COI gene, (B) 18S rRNA gene, (C) H3 gene, and (D) consensus tree of concatenated COI, 18S, and H3 sequences.

FIGURE 8. Adult male of Oecleus borealis; (A) dorsal view, (B) lateral view, (C) dorsal view of aedeagus, (D) ventral view of aedeagus, (E) right lateral view of aedeagus, (F) left lateral view of aedeagus, (G) ventral view of terminalia, and (H) lateral view of terminalia; scale = 1 mm.

Tables

TABLE 4. Pairwise comparison based on the 18S rRNA locus to demonstrate intra (orange) and inter (blue) generic variability by percent nucleotide difference (bottom left) and standard error (top right).

		1	2	3	4	5	6	7	8	9	10	11	12
1	Oecleus dormido sp. n.		0.001	0.002	0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.003
2	Oecleus borealis	0.002		0.002	0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.003
3	Oecleus mackaspringi	0.005	0.006		0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.004	0.004
4	Myxia belinda	0.022	0.023	0.023		0.003	0.003	0.004	0.004	0.004	0.004	0.004	0.004
5	Myxia delta	0.024	0.026	0.024	0.009		0.001	0.004	0.004	0.004	0.004	0.004	0.004
6	Myxia hernandezi	0.023	0.025	0.025	0.009	0.001		0.004	0.004	0.004	0.004	0.004	0.004
7	Haplaxius pocococo	0.023	0.025	0.022	0.023	0.021	0.022		0.003	0.002	0.004	0.004	0.004
8	Haplaxius lunatus	0.021	0.023	0.020	0.023	0.023	0.023	0.011		0.002	0.004	0.004	0.004
9	Haplaxius crudus	0.020	0.021	0.019	0.020	0.019	0.020	0.005	0.008		0.003	0.004	0.004
10	Nymphocixia caribbea	0.023	0.024	0.021	0.022	0.021	0.022	0.017	0.017	0.014		0.003	0.004
11	Nymphocixia unipunctata	0.025	0.026	0.024	0.026	0.027	0.027	0.023	0.020	0.020	0.010		0.004
12	Melanoliarus chuliotus	0.016	0.017	0.018	0.022	0.025	0.025	0.026	0.023	0.023	0.026	0.028