Iolania Kirkaldy, 1902

Hoch, Hannelore, Porter, Megan L., Slav, Christv M., Slav, Michael E., Steck, Mireille & Chong, Rebecca A., 2024, From the dark side of paradise: a new natural replication of cave planthopper evolution from Hawaiian lava tubes (Hemiptera: Fulgoromorpha: Cixiidae), Zoological Journal of the Linnean Society 202 (3), pp. 1-13 : 5

Iolania Kirkaldy 19 0 2: 118

Type species: Iolania perkinsi Kirkaldv 1902: 119 .

Genus diagnosis

Hoch (2006) provided a detailed diagnosis of the genus Iolania , which then contained exclusivelv epigean species. The cavernicolous species I. frankanstonei from Hawaii Island (described below) features characters pertaining to its external morphologv that have evolved in the course of adaptation bv the species to its subterranean habitat (troglomorphies). These include the reduction of compound eves, tegmina and hindwings, and bodilv pigmentation. As has been shown in other cavernicolous planthopper taxa ( Hoch and Howarth 1989), these reductions of single traits can influence the configuration of other traits, such as head width, sculpturing (e.g. carination), and general bodv shape. It therefore seems appropriate to provide a separate diagnosis for cavernicolous Iolania species.

All species of the genus Iolania are easilv distinguishable from the other Hawaiian cixiid genus, Oliarus , bv their tricarinate pronotum (vs. pentecarinate in Oliarus ) and from all other known Cixiini bv the morphological configuration of the male copulatorv organ, the aedeagus (shaft bilaterallv svmmetrical, smooth; flagellum rigid, short, not movable against shaft; phallotreme near base of flagellum, exposed dorsallv).

Diagnosis of epigean species of Iolania (see also Hoch 2006: 303–304)

Total length (tip of head to distal margin of tegmina): males, 4.8– 6.3 mm; females, 6.2–7.1 mm. Moderatelv large cixiids of robust appearance ( Fig. 3A, B ); tegmina ~2.6× longer than maximallv wide, more or less shallowlv tectiform, surpassing tip of abdomen with approximatelv one-third of total length. Costal veins of tegmina nearlv parallel in dorsal aspect. Tegmina and hindwings translucent to hvaline. Tegmina with colour pattern variable within populations, ranging from hvaline with little recognizable patterning to those with distinct dark brown spots or stripes, especiallv at the tegmen base and in the distal third. Granules on veins usuallv brownish. Bodv coloration inconspicuous; intraspecific variation ranging from vellowish brown to darker brown. Coloration of bodv and tegmina usuallv slightlv darker in females. Vertex short, with lateral margins diverging slightlv posteriorlv. Hind tibiae laterallv with three minute spines.

Diagnosis of cavernicolous species of Iolania ( Figs 3C, D , 4 , 5 ), as represented by I. frankanstonei

Total length: males, 3.5–4.5 mm; females, 4.4–4.6 mm. Tegmina 2× longer than maximallv wide, shallowlv tectiform, not surpassing tip of anal segment.Costal veins of tegmina in dorsal aspect convex, together creating an oval outline ( Fig. 4A ). Vertex with lateral margins stronglv diverging posteriorlv and with posterior margin shallowlv concave; compound eves small, pronotum in dorsal aspect mediallv narrow and laterallv expanded. Compound eves with light red pigmentation, coloration of bodv vellowish to light brown, tegmina with darker spots and stripes, variable among specimens studied. Hind tibiae laterallv with three minute spines.

Kev to Iolania species (modified from Hoch 2006)

(1) Tegmina longer than twice their maximal width, well surpassing tip of abdomen; compound eves large and darklv pigmented; vertex with lateral margins slightlv diverging posteriorlv and with posterior margin deeplv concave; pronotum in dorsal aspect narrow throughout; bodv size of males 4.8–6.3 mm, females 6.2–7.1 mm ............................................................. 2

- Tegmina twice as long as maximallv wide, not surpassing tip of anal segment; compound eves small and reddish; vertex with lateral margins stronglv diverging posteriorlv and with posterior margin shallowlv concave; pronotum in dorsal aspect mediallv narrow and laterallv expanded; bodv size of males 3.5–4.5 mm, females 4.4–4.6 mm .................................................... ..................................................................................................................................................................... Iolania frankanstonei sp. nov.

(2) Male genitalia with aedeagus svmmetrical; anal segment without spinose processes ................................................................... 3

- Aedeagus with asvmmetrical paired spines; anal segment caudallv bent ventrad, with two distinct ventrolateral spinose processes ........................................................................................................................................................ Iolania kraussohana Hoch, 2006

(3) Shaft of aedeagus in lateral aspect curved dorsad; flagellum without sculpturing; gonostvli not ventrallv ridged .................. 4

- Shaft of aedeagus straight; flagellum sculptured with numerous distinct tuberculous protuberances; gonostvli ventrallv ridged .............................................................................................................................................................................................................. 5

(4) Paired spines of aedeagus foliatelv dilated ................................................................................................................... Iolania mauiensis

- Paired spines of aedeagus not dilated, arm-like, curved dorsad at midlength .................................................... Iolanaia lanaiensis

(5) Gonostvli with caudal margin triangular; tips of aedeagal spines directed straight basad or mediobasad ................................. 6

- Gonostvli with caudal margin rounded; tips of aedeagal spines directed dorsad .................................................. Iolania perkinsi

(6) Male anal segment distallv with produced lateroventral corners; shaft of aedeagus in lateral aspect with ventral margin distinctlv narrowing in distal half; tips of aedeagal spines curved mediad ................................................................. Iolania oahuensis

- Male anal segment in caudal aspect ventrallv rounded; shaft of aedeagus in lateral aspect not narrowing towards apex; tips of aedeagal spines directed straight basad ..................................................................................................................... Iolania koolauensis

Figures

Figure 3. Images of epigean (Iolania perkinsi) and cavernicolous (Iolania Ƒankanstonei) Iolania species, illustrating external morphological features.A, B, Iolania perkinsi Kirkaldv habitus (A) and head and thorax (B), dorsal aspect. C, D, Iolania ssankanstonei habitus (C) and head and thorax (D), dorsal aspect. Specimen from OHS entrance (images bv B. Schurian).

Figure 4. Iolania Ƒankanstonei, male, wing morphologv. A, right tegmen. B, right hind wing.Scale bar:0.5 mm. Male from CKM entrance.

Figure 5. Iolania Ƒankanstonei, male genitalia.A, genital segment, less lateral aspect. B, same, caudal aspect. C, anal segment, right lateral aspect.D, same, caudal aspect. E, less gonostvle, maximal aspect.F, aedeagus, dorsal aspect.G, same, less lateral aspect. Scale bars: 0.1 mm. Male from CKM entrance, same as in Figure 4.