Felisacus Distant, 1904

Namyatova, Anna A. & Cassis, Gerasimos, 2016, Revision And Phylogeny Of The Fern-Inhabiting Genus Felisacus Distant (Insecta: Heteroptera: Miridae: Bryocorinae) Anna A. Namyatova And Gerasimos Cassis, Bulletin of the American Museum of Natural History 2016 (403), pp. 1-169 : 25-28

Felisacus Distant, 1904

Liocoris Motschulsky, 1863: 86 (gen. nov.; type species Liocoris glabratus Motschulsky, 1863 , by monotypy); Distant, 1904: 438 (junior homonym of Liocoris Fieber, 1858 (Hemiptera) ; Carvalho, 1957: 103 (catalog); Schuh, 1995: 510 (catalog).

Felisacus Distant, 1904: 438 (replacement name for Liocoris Motschulsky, 1863 ); Kirkaldy, 1906: 134 (list); Reuter, 1910: 163 (catalog); Poppius, 1911: 3 (description); Poppius, 1912: 181 (description); Bergroth, 1922: 55 (list); China, 1944: 174 (key to genera); Carvalho, 1952: 55 (catalog); Woodward, 1954: 41 (discussion, description); Carvalho, 1955: 34 (key to genera); Carvalho, 1957: 103 (catalog); Woodward, 1958: 236 (discussion); Carvalho, 1981: 51, 61 (key to genera, description, key to species); Cassis and Gross, 1995: 141 (catalog); Schuh, 1995: 510 (catalog); Lin, 2000: 233 (key to species).

Hyaloscytus Reuter, 1904: 1 (original description; type species: Hyaloscytus elegantulus Reuter, 1904 , by monotypy); Kirkaldy, 1906: 134 (list); Reuter, 1910: 153 (catalog); Poppius, 1911: 3 (synonymy); Carvalho, 1957: 103 (catalog); Schuh, 1995: 510 (catalog)

Felisacoris Carvalho, 1956: 24 (gen. nov.; type species: Felisacoris ponaponensis Carvalho, 1956 , by monotypy); new synonymy.

DIAGNOSIS: Felisacus is separated from other bryocorine taxa by the following characters: labial segments I and II almost as long as wide (Namyatova et al., 2016: figs. 6D, E, 9C), sometimes twice as long as wide, but each of them distinctly shorter than segment III; pronotum with two pairs of punctures laterally on sulcus delimiting calli and with pair of punctures ante- riorly to sulcus (Namyatova et al., 2016: fig. 4E); unique structure of pleura with distinct triangular scent gland evaporative area, oval spiracle, surrounded with few evaporative bodies; mesopleural/metapleural suture inferiorly obsolete (Namyatova et al., 2016: fig. 14B); parempodia asymmetrical, outer parempodium shorter than inner one (Namyatova et al., 2016: fig. 20A, C).

DESCRIPTION: Male. Body small and elongate, 2–4 mm. COLORATION (figs. 4–7): Head, pronotum, and thoracic pleura usually yellow or pale brown, sometimes with brown to dark brown marking or uniformly dark brown to black; hemelytron often whitish yellow and translucent, often with brown to dark brown C-shaped marking or at least with dark stripe along inner margin of corium; coloration of cuneus varying from whitish yellow to dark brown, sometimes with reddish tinge or bright red; membrane sometimes with grayish tinge or brown; appendages of same color or paler than dorsum, usually whitish yellow, yellow or pale brown, antennal segment I sometimes dark brown to black; femur sometimes with brown or reddish bands. SURFACE AND VESTITURE: Body mostly smooth, often with shallow punctures; lateral margins of scutellum with shallow striations (Namyatova et al., 2016: fig. 11A, B); R+M impunctate or with shallow punctures; body clothed with pale simple setae, mostly missing on hemelytron, only with few setae on clavus and anterior margin of corium; trichobothria surrounded by dense fields of trichoma.

STRUCTURE: Head: Hypognathous, in dorsal view eyes distinctly removed from pronotum, roundish; area between head to pronotum straight or slightly swollen, sometimes with transverse depression, delimiting occipital region; longitudinal sulcus present, its length varying from very short to almost reaching anterior margin of head; frons straight, not convex (Namyatova et al., 2016: fig. 4E); in anterior view head slightly higher than wide, eye oval, shorter than head height, its inner margin distinctly concave; clypeus as long as eye, its base placed above inferior margin of eye; antennal fossa tubercu- late, shorter than half of eye height, attached near midline of eye, its inferior margin not reaching inferior margin of eye (Namyatova et al., 2016: fig. 3C); in lateral view eye oval, its inferior margin not reaching maxillary plate; antennal fossa inserted slightly above base of clypeus; clypeus slightly swollen basally; buccula short and ringlike, tightly binding labial segment I; gula long and straight, 2–3× as long as buccula (Namyatova et al., 2016: fig. 6D, E). Antenna: Slightly shorter than or subequal to body length; length of segment I slightly greater than or subequal to head width, cylindrical or swollen medially (Namyatova et al., 2016: fig. 8A, B); segment II subequal to or slightly longer than segment I, segment III as long as or slightly longer than segment II; segment IV usually slightly shorter than or subequal to half the length of segment I. Labium (Namyatova et al., 2016: figs. 6D, E, 9C): Length variable, reaching from posterior margin of prosternum to posterior margin of metasternum; labial segments I and II shortened, often wider than long or as long as wide, rarely somewhat longer than wide; labial segment III sometimes telescoped into segment II; segment III usually 2–3 times longer than, rarely as long as segments I and II combined; segment IV usually almost twice as long as segment III, rarely only slightly longer than segment III. Thorax: Pronotum (Namyatova et al., 2016: figs. 4E, 6D). Length of pronotum subequal to its width at base; collar often more or less delimited laterally and medially, in F. ponaponensis collar not delimited; calli fused, delimited with sulcus posteriorly; pair of punctures of lateral side of this sulcus and anteriorly to sulcus present. Scutellum and mesoscutum (Namyatova et al., 2016: fig. 11A, B). Sulcus between scutellum and mesoscutum with pair of punctures medially; apex of scutellum acute. Pleura (Namyatova et al., 2016: fig. 14B). Meso- and metapleuron not separated, suture between them obsolete inferiorly; mesothoracic apodeme round; metathoracic spiracle open and oval, with single row of evaporative bodies inferiorly; opening of scent gland distinct, surrounded by triangular evaporative area; met- epimeron narrow, without lobe; posterior margin of metasternum straight. Hemelytron (Namyatova et al., 2016: figs. 11A, 13E, F): Clavus with row of punctures, medial margin longer than scutellum; medial fracture very short; R+M long, reaching cuneus, impunctate or with some very small and shallow punctures; claval commissure with straight margins; cuneus 2–4 times as long as wide at base, its inner margin straight or convex; membrane with single or two cells, often vein between them faint; cells not reaching apex of membrane, forming right angle, shorter than distance between apex of cell and apex of membrane. Legs: Forecoxae contiguous with each other, middle and hind coxae separated (Namyatova et al., 2016: fig. 17C), in lateral view coxae short, not reaching upper margin of thoracic pleura; femora slender, not modified (Namyatova et al., 2016: fig. 18E), forefemur shorter than length of head and pronotum combined; hind femur longer than other femora; tibia straight; tarsal segments almost subequal in length, segment III dilate (Namyatova et al., 2016: fig. 19C). Pretarsus (Namyatova et al., 2016: fig. 20A–C). Unguitractor with three rows of contiguous tiles, those of middle row straight; basal claw spicules absent; claw broadly rounded, often with basal subtriangular tooth, sometimes only with short outgrowth basally; claw without medial or apical tooth; parempodia setiform, tapering toward apex, asymmetrical, with outer parempodium shorter than inner one; pseudopulvilli present, attached to unguitractor and base of claw, distinctly longer than claw. Genitalia: Genital capsule (figs. 14, 15; Namyatova et al., 2016: fig. 22L) subtriangular, 1–1.5× as long as wide; without supragenital bridge, sometimes with outgrowths on apical margin of ventral wall and swelling at sides. Parameres (Namyatova et al., 2016: figs. 11–13, fig. 22J, K). Right paramere longer than left, parameres usually sickle shaped or L-shaped, but sometimes right paramere straight or left paramere of irregular shape. Aedeagus (Namyatova et al., 2016: figs. 8–10, figs. 22I, M) phallotheca moderately sclerotized; endosoma voluminous, subdivided into vesica and conjunc- tiva (fig. 10; Namyatova et al., 2016: figs. 22I, M), with or without long spicules, rarely with fields of small spicules or with single small claw-shaped spicule; ductus seminis with small sclerotized ring around secondary gonopore, sometimes apical half of ductus seminis sclerotized, straight or hook shaped apically.

Female. Similar to male, not showing sexual dimorphism in external characters, but females usually slightly larger than males. Genitalia (fig. 16; Namyatova et al., 2016: figs. 23F, G): Dorsal labiate plate with or without sclerotized rings, sometimes with semioval sclerite medially; often without striations, smooth, sometimes with striations, rarely with membranous longitudinal ridge; lateral oviducts attached medially or in posterior half; place of attachment on spermathecal gland varying, often medially or near anterior margin; posterior wall of bursa copulatrix membranous, with or without small tubercles, sometimes with membranous lobe anteriorly; vulva indistinct, without sclerotization.

DISTRIBUTION: The genus is mostly distributed in tropical areas of the Indo-Pacific region. Felisacus is distributed mainly in Australian and Oriental regions, with 34 and 22 species respectively. Three species are also known from the Ethiopian region. Felisacus jacobsoni , F. javanus , F. longiceps , and F. magnificus are distributed in the Australian and Oriental regions. Most species inhabit small areas, especially, those found on islands; however, some species have broader distribution: F. bellus Lin, 2000 (from southern China to southern parts of Vietnam and Thailand), F. elegantulus (east coast of Australia and New Zealand), F. filicicola ( Samoa, Fiji, Vanuatu), F. insularis (southern China, Japan, Thailand, Vietnam), F. javanus (from Malay to New Guinea), F. longiceps (from South China to Ambon Is.), F. magnificus (from Thailand and Japan to Lombok Is.).

The phylogeny of Felisacus is divided into two main clades (3 and 14) and a single small Asian clade 2 with unclear affinities (figs. 1–3). Clades 3 and 14 are broadly overlapping in the Oriental region. Clade 3 includes 12 species of which eight are distributed in southeast Asia. Only five species are known from Australian region, including a single species each from mainland Papua New Guinea, New Britain, and Micronesia, and two species from the Solomon Islands (fig. 22). Species of clade 14 are distributed in the Australian and Oriental regions, ranging from southern China and Japan to the southeast coast of Australia and New Zealand; it is also widely distributed in islands of the southwest Pacific and occurs in Madagascar (fig. 22). This pattern is similar to Coridromius , which is distributed in Indo-Pacific although its two main subclades are largely divided at Wallacea (Tatarnic and Cassis, 2010).

HOST PLANTS: Little is known about the feeding habits of Felisacini , but they are assumed to be fern feeders based on their common and specialized association with ferns (15 species of Felisacus of 55 described with host-plant data). Fourteen species have been collected from ferns ( Kirkaldy, 1908; Usinger, 1946; Miyamoto, 1965; Woodward, 1958; also, this work). The host-plant records of Felisacus do not indicate phylogenetic restrictedness to any fern clade, and are instead known from distantly related genera, including Nephroplepis Schott, Polystichum Roth (Polypodiaceae) , Diplazium Schwartz , Plesioneuron Holttum (Aspleniaceae) , Pteris L. ( Pteridaceae ), Hypoplepis Bernh., Pteridium Gled. ex Scop. (Dennstaedtiaceae) , Schizaea Sm. (Schizaeaceae) (see Christenhusz and Chase, 2014, for the latest phylogeny of ferns). Moreover, there are cases where a Felisacus species is known from two or more species, with these multiple fern species belonging to different families. This broad fern affiliation is also found in the tribe Bryocorini (Konstantinov and Knyshov, 2015) . Felisacus elegantulus , F. lindbergae , and F. nigrescens have been recorded from angiosperms, but these likely represent sitting records, because records are either singletons or doubletons.

DISCUSSION: Felisacus is well delimited and although the species within it vary considerably in salient and genital structures, the genus is not similar to any other genus of Miridae . Here we synonymize Felisacoris Carvalho, 1952 , with Feli- sacus. Although the single species of Felisacoris , F. ponaponensis , is morphologically distinct, it is undoubtedly nested within Felisacus , in particular in clade 3, and possesses male genitalia very similar to other species in this group (see figs. 1–3, 10).

Although Felisacus is a speciose taxon, containing 55 species, there are more undescribed species known to us. We examined such specimens belonging to the Bishop Museum, and likely represent new species, but we refrained from treating them as they were in poor condition.

Confusion exists in the literature concerning the type species and synonymy of the valid genus and junior synonyms. In particular, the type species of Liocoris is L. glabratus , which Carvalho (1957) listed as being synonymous with Hyaloscytus elegantulus , which he attributed to Poppius (1911). This is in error in both the relevant available names and the date of Poppius’ work. Poppius (1911) redescribed Felisacus and F. glabratus , synonymized Hyaloscytus with Felisacus , but made no mention of species synonymy. Carvalho (1957) indicated that Poppius (1911) synonymized Felisacus glabratus with Hyaloscytus elegantulus . Kerzhner and Jansson (1985) indicated that Carvalho’s citation of Poppius was incorrect, and identified Poppius (1914) as the work with the synonymy of Feliascus glabratus and Hyaloscytus elegantulus javanus , and not the nominotypical subspecies of the latter. Cassis and Gross (1995) followed the Poppius attribution of Kerzhner and Jansson (1985) but also indicated that H. elegantulus was synonymous with F. glabratus (as Liocoris ), following Carvalho’s (1957) species nomenclatorial history of F. glabratus . Schuh (1995) cited Liocoris glabratus as the type of Felisacus and gave it as a separate species with no synonyms. We revise the status of Hyaloscytus elegantulus javanus in this work and raise it to species rank.