Cixius palmirandus Hoch & Naranjo, 2025

Hoch, Hannelore, López, Heriberto, Naranjo, Manuel, Aguín-Pombo, Dora & Oromí, Pedro, 2025, Endless forms most wonderful: Four new cavernicolous planthopper species (Hemiptera, Fulgoromorpha, Cixiidae and Meenoplidae) from the Canary Islands, Subterranean Biology 51, pp. 61-101 : 61-101

Cixius palmirandus Hoch & Naranjo sp. nov.

Figs 4 , 5 A – F

Material examined.

Holotype: Spain • male; Canary Islands, La Palma, Cueva Honda de Miranda ; 28.63744940, - 17.78849367; 17 Oct. 2015; M. Naranjo leg. (50353 DZUL).

Diagnosis.

Cixius palmirandus is similar to the other cavernicolous Cixius species from La Palma, C. palmeros Hoch & Asche, 1993 and C. pinarcoladus Hoch & Asche, 1993 in habitus (degree of troglomorphy), body size, general configuration of the male genital morphology, but differs in several characters: upper portion of frons smooth (vs. pustulate as in C. palmeros and C. pinarcoladus ), mesonotum with lateral carinae attaining posterior margin (unlike in C. palmeros ), tegmen with Y-vein (Pcu, A 1, Pcu + A 1) complete (vs Y-vein incomplete in C. palmeros and C. pinarcoladus ), genital styles with expanded distal portion highly elongate (vs spoon-shaped in C. palmeros and C. pinarcoladus ), and aedeagus shaft ventrally with an obtuse ridge which is apically rounded, concave and distinctly curved ventrally (vs apically with an obtuse tip, as in C. palmeros , or directed straight caudally, as in C. pinarcoladus ).

Description.

Habitus. Strongly troglomorphic with compound eyes absent, tegmina, wings and bodily pigmentation strongly reduced.

Body length. Male 3.9 mm (n = 1)

Colouration. Head, thorax and abdomen stramineous / yellowish, lateral carinae of head and lateral carinae of pronotum in anterior portion slightly darker. Antennae and legs whitish, tegmina translucent with costal vein yellowish, other veins unpigmented.

Head. Vertex short and wide, not separated from frons by a transverse carina, i. e., frons continuously rounded into vertex. Vertex laterally near posterior margin of head with two shallowly concave areas. Frons convex, in ventral view ca. twice as wide as medially long, smooth, without median carina, lateral carinae strongly ridged, directed laterally. Frontoclypeal suture highly vaulted. Post- und anteclypeus smooth, without median carina. Post- and anteclypeus together ca. 2.8 × longer than frons medially. Rostrum elongate, well surpassing hind coxae, 2 nd joint longer than 3 rd. Compound eyes and ocelli absent, the former position of the lateral ocelli faintly recognizable by a light roundish spot anteriorly of antennae. Antennae with scape very short, ring-like, pedicel globose, with sensory plaque organs feebly recognizable; antennae shielded anteriorly by lateral margins of frons.

Thorax. Pronotum short, ca. 4 × wider than medially long, and 1.5 × wider than maximum width of head; indistinctly tricarinate: median carina obtuse, lateral carinae distinct in anterior portion, diverging laterally, gradually vanishing; posterior margin of pronotum shallowly incised. Mesonotum slightly vaulted, ca. 1.3 × wider than medially long, in midline ca. 3 × the length of pronotum; tricarinate, with carinae obtuse and faintly recognizable, lateral carinae attaining posterior margin. Tegulae vestigial. Tegmina strongly reduced, venation as in Fig. 4 . Costal vein in anterior and distal part of tegmen conspicuously wide; „ Y-vein “ (Pcu, A 1, Pcu + A 1) preserved and recognizable. Tegmen ca. 1.6 × longer than maximally wide, attaining, respectively slightly surpassing posterior margin of third abdominal tergite. Longitudinal veins sparsely beset with bases of setae. Wings vestigial. Metatibiae laterally with 3 minute spines, distally with 6 teeth, grouped 5 + 1, lateral tooth longest. First and second metatarsal joints with 4 apical teeth, lateral ones longer than median ones. First metatarsal joint about as long as 2 nd and 3 rd joints together. Pretarsal claws slender, arolium small.

Male genitalia. Genital segment bilaterally symmetrical, in caudal aspect ca. 1.6 × higher than maximally wide, and in lateral aspect ca. 4 × longer ventrally than dorsally, caudal margins laterodorsally slightly expanding into rounded lobes, their margins beset with a cluster of long setae; medioventral process wide at base, distally tapering, tip in ventral view slightly incised, dorsal surface of medioventral process concave. Anal segment tongue-shaped, lateral margins straight, without ventral lobes, parallel from base to level of anal style, distally slightly tapering; anal segment distally of anal style bent ventrally in a ca. 45 ° angle, caudal margin produced into two short rounded lobes. Genital styles narrow in basal third, distally expanding, expanded portion elongate, distally rounded, medially concave; genital styles with dorsal margin of narrow portion and external surface of expanded portion densely beset with setae. Genital styles in repose joining in midline over nearly their whole length ventrally, nearly completely covering the aedeagus. Aedeagus with basal part (shaft) tubular, slender, slightly compressed in basal two thirds, ventrally near base with two small rigid spines directed caudally; shaft ventrally with an obtuse longitudinal ridge which is apically rounded and in upper part slightly curved ventrally. Shaft subapically with a bulbous projection dorsally and right laterally, shaft apically with two sturdy movable spinose processes: left lateral one shallowly S-shaped, tip in repose directed basally, right lateral one slightly shorter than left lateral one, strongly curved and in repose directed right-lateroventrally, its tip pointing right laterally. Distal part of aedeagus (flagellum) in repose bent dorsally, narrow, surpassing midlength of shaft, but not attaining base of shaft; dorsally with a longitudinal ridge which is produced into a short, stout spine at apex, tip of flagellum directed right laterally.

Female. Unknown.

Etymology.

The species epithet is an adjective in nominative singular, and a combination from the island of the type locality, La Palma, and the name of the cave, Cueva Honda de Miranda. The gender is masculine.

Distribution.

Known from the type locality in the east of La Palma, municipality of Breña Alta (Fig. 1 ). Endemic to La Palma.

Ecology and behavior.

Cueva Honda de Miranda is a lava tube located at 417 m a. s. l. in the eastern slope of the island. The potential vegetation in this area corresponds to a dry laurel forest (Visneo mocanerae - Arbutus canariensis sigmetum) ( Del Arco and Rodríguez 2018). Currently, this space is occupied by agricultural plots and substitution scrub. The cave is a labyrinthic lava tube with over 20 galleries and 1 km of total development ( Dumpiérrez et al 2000), in which seven troglobiont species have been recorded so far: the amphipod Palmorchestia hypogaea Stock & Martín, 1988 , the isopod Halophiloscia microphthalma Taiti & López, 2008 , the cockroach Loboptera fortunata Krauss, 1892 , the thread-legged bug Collartida tanausu Ribes, Oromí & Ribes, 1998 , and the beetles Licinopsis angustula Machado, 1987 , Domene benahoarensis Oromí & Martín, 1990 and Laparocerus dacilae García, 1998 . The gallery with the presence of C. palmirandus is located relatively close to the entrance to the cave, in which predominates a wide section, a high relative humidity and the presence of roots. The only specimen collected of C. palmirandus was dead but in good conditions for the formal descriptions of the new species. In this sector, an American cockroach nymph ( Periplaneta americana ) was observed, which may indicate local contamination by sewage.

Ecological classification. Cixius palmirandus sp. nov. displays several troglomorphic characters: absence of compound eyes and ocelli, strongly reduced tegmina and vestigial wings, and light body coloration. Although there is no information on the behaviour of the species, it is certainly unable to fly. The phenotypical configuration of eyes and wings suggests that it is restricted to the subterranean environment and likely to complete the entire life cycle underground. According to the criteria provided by Sket (2008), and more recently by Howarth and Moldovan (2018 a, b), we regard C. palmirandus sp. nov. as an obligate cavernicole, or troglobiont.

Conservation status.

Cueva Honda de Miranda is located in an area of the island where the potential vegetation should be dry laurel forest (Del Arco and Delgado 2018), but it is currently heavily transformed into a rural environment dotted with scattered homes and agricultural fields. The sewage sanitation system in the area is non-existent, and wastewater is generally discharged directly into underground wells, which are gradually contaminating the subsurface. Additionally, the chemicals used in the fields also accumulate in the subterranean environment over the years. Under these circumstances, the underground habitat loses its suitability for native subterranean species, as they are very sensitive to such habitat alterations. Furthermore, with this degradation, the underground habitat begins to be colonized by invasive species that thrive in these types of contaminated environments, competing with and displacing the native subterranean fauna. The detection of Periplaneta americana ( Linné, 1758) in some areas of Cueva Honda de Miranda is a clear indication that its subterranean environment is likely undergoing such environmental degradation process. Nevertheless, there is no regular monitoring of the subterranean species populations present in the cave, which would provide precise information on whether they are experiencing some decline (Rafael García, personal comment). The sporadic sampling conducted so far in the cave has allowed for the capture of the only known specimen of Cixius palmirandus sp. nov., but the lack of continuity in these sampling efforts does not allow us to determine whether this species is scarce due to being rare, due to naturally low populations, or because they have indeed suffered a decline due to the deterioration of the subterranean environment. According to the IUCN criteria for assessing whether a species falls into one of the threat categories on its Red List, Cixius palmirandus meets criterion D 2 (see IUCN 2022) due to its very restricted area of occupancy, which is less than 20 km ², and the fact that it is known from only one location. Such circumstances make this species highly vulnerable to the impacts of human activities and stochastic events in a short time frame, potentially leading to its classification as Critically Endangered or even Extinct in the near future. Given these conditions, this new species should be classified as Vulnerable according to the IUCN criteria.

Remarks.

The only known individual of this species, a male, was apparently collected and preserved in ethanol soon after the adult molt: the larval skin is still partially attached, and the cuticle still soft, thus the frons is distorted and the aristae of the antennae are missing. However, the male genital capsule appears to be fully sclerotized.

Figures

Figure 1. The Canary Islands and distribution of the new species described. Black triangle: Cixius palmirandus Hoch & Naranjo, sp. nov.; Black circle: Tachycixius gomerobscurus Hoch & Oromí, sp. nov.; Black stars: Cixius theseus Hoch & Aguín-Pombo, sp. nov.; Black square: Meenoplus skotinophilus Hoch & López, sp. nov. (https://commons.wikimedia.org/wiki/File:Map_of_the_Canary_Islands.svg; https://catalogo.idecanarias.es/geonetwork/srv/spa/catalog.search#/metadata/spagrafcan_MTLWMS_20160101).

Figure 4. Cixius palmirandus Hoch & Naranjo, sp. nov. Habitus male (holotype). Scale bar: 0.5 mm.

Figure 5. Cixius palmirandus Hoch & Naranjo, sp. nov. Male genitalia (holotype) A genital segment, right lateral aspect B same, ventral aspect C anal segment, caudal aspect D anal segment, aedeagus, genital style, in situ, left lateral aspect E aedeagus, right lateral aspect F same, ventral aspect. Scale bar: 0.1 mm.