Xerosoma Serville 1831

Engelking, Phillip Watzke, Ghirotto, Victor Morais, Crispino, Edgar Blois, Büscher, Thies H., Heleodoro, Raphael Aquino, Neves, Pedro Alvaro Barbosa Aguiar & Bispo, Pitágoras da Conceição, 2023, Fig. 23. Saiva formosana Kato, 1929, male genitalia. A in Lanternflies (Hemiptera: Fulgoridae) of Taiwan., Zoological Studies 62 (31), pp. 1-59 : 5-9

Xerosoma Serville 1831

Xerosoma Serville 1831 (61); Gray 1835 (26) [synopsis]; Serville 1838 [1839] (274), pl. 6, Fig. 3 [synopsis]; Blanchard 1840 (14, 18) [synopsis]; Westwood 1859 (103) [catalogue]; Stål 1875a (59, 99) [description of X. senticosa , X. spinosa transferred to Crexoylus]; Stål 1875c (20) [systematic]; Kirby 1890 (572) [systematic]; Rehn 1904 (101) [description of X. glypteomerion ]; Kirby 1904 (416) [synopsis]; Redtenbacher 1906 (143) [key to genera, description of X. vignieri and X. michaelis , description of the male of X. canaliculatum ]; Shelford 1909 (375) [synopsis in part]; Bradley and Galil 1977 (202) [synopsis in part]; Bragg 2001 (645) [type species data]; Zompro 2004a (111, 323) [ Dinelytron neptunus Kaup 1871 synonymized under X. canaliculatum ]; Otte and Brock 2005 (342 [catalogue]); Araujo and Garraffoni 2012 (236) [synopsis]; Conle et al. 2020 [ X. glyptomerion Rehn 1904 and X. vignieri Redtenbacher, 1906 transferred to Isagoras ].

Species included: Xerosoma canaliculatum , Xerosoma michaelis , and Xerosoma nannospinus sp. nov. The type species is X. canaliculatum , by original monotypy.

Diagnosis: Xerosoma is differentiated from other Xerosomatinae by a pair of spines in the posterior part of the pronotum, the presence of wings in both sexes, conspicuous keels in terga VIII–X in both sexes, and the prickly anterior femur of females.

Remarks: Monophyletic Xerosomatinae was recovered in molecular phylogenetic studies ( Simon et al. 2019; Bank and Bradler 2022). However, there is a lack of a detailed evaluation of the morphological characteristics shared among its members for a decisive approach. Overall characteristics shared b y X e r o s o m a t i n a e a n d c o n t r a s t i n g w i t h o t h e r Pseudophasmatidae includes a more rugose or granulose body surface, a longer tegmina, a shorter subgenital plate showing the enlarged gonapophyses in females, and a poculum usually smaller and flattened in males. Xerosoma has all of these characteristics.

Key to ñ of Xerosoma

( Fig. 2 )

1a. Hindwings strongly reduced, not reaching the abdomen .............. ................................................................................... X. michaelis

1b. Hindwings at least reaching abdominal segment VI .................. 2

2a. Spines in the posterior part of the pronotum are strongly pronounced forwardly, reaching a third of the pronotum in length ............................................................................ X. canaliculatum

2b. Spines in the posterior part of the pronotum are reduced, not reaching a third of the pronotum in length .................................... ................................................................. X. nannospinus sp. nov.

Key to ò of Xerosoma (males unknown for X. michaelis )

( Fig. 3 )

1a. Spines in the posterior part of the pronotum are strongly pronounced forwardly, reaching a third of the pronotum in length ............................................................................ X. canaliculatum

1b. Spines in the posterior part of the pronotum are reduced, not reaching a third of the pronotum in length .................................... ................................................................. X. nannospinus sp. nov.

Redescription: Brachypterous to fully winged. Sexual dimorphism marked with females significantly more robust than males. Male and eggs are not known for X. michaelis . Body length of 45.4–67 mm for ò and 55–65 mm for ñ.

Head slightly longer than wide, slightly dorsoventrally compressed; vertex almost flat, gently round or prominent posteriorly; surface covered with fairly prominent granules and frequently with a longitudinal line centrally. Ocelli reduced in ò, absent in ñ. Antennae slender, reaching abdominal segments II or III in ñ, or segments VI to slightly longer than the body in ò.

Thorax and abdomen roughly cylindrical. Pronotum slightly longer than wide, slightly shorter to about the same length as the head; wrinkled and covered with granules to spines, at posterior half with a pair of acute spines, small or prominent, pointing upwards or curved anteriorly. Mesonotum stouter and 1.8–2.5× longer than the pronotum, with a pair of dorsolateral carinae. Mesonotum rugose and bearing small to large granules, with the largest presented in pairs centrally, one at each carina. Mesepimeron with a longitudinal rugose carina with larger granules near the posterior region. Metanotum and middle segment equally longer, in the same thickness, or slightly more robust than the posterior portion of mesonotum. Metanotum dorsally glabrous, darker, granulated ventrally.

Brachypterous or fully winged. Tegmina suboval, posterior margin rounded or truncated; with marked venation and distinct shoulder pads; barely reaching the median segment to reaching tergum II. Hindwings reaching the center of the median segment or tergum VI in ñ and tergum VIII in ò; when fully winged, anal area tessellated.

Legs smooth and slender in ò. In ñ, femora I and II with undulate to conspicuously sharp serrations laterally; femora III unarmed. Tibiae slightly granulate in ñ. Profemora basally curved, dorsoventrally compressed, slightly longer than the mesothorax; hind legs slightly longer than the abdomen. Basitarsi 2–2.5× longer than the respective following tarsomeres.

Abdominal segments longer than wide. When fully winged, terga I–V dorsally glabrous and centrally black. Terga laterally keeled, conspicuously larger forming lateral lobes in VII–IX. Tergum X with a pair of rough carinae, more pronounced in females; dorsally with elevations apically. Tergum X tectiform, slightly longer than IX, with two or three apical carinate projections in females. Apical inner surface of tergum X with about 10 in-curving teeth in ò. Vomer significantly reduced, not sclerotized, showing as a basal bump 4× wider than long. Epiproct small, discreet. Paraprocts deeply incised medially in ò and posteromedially incised in ñ. Sternum IX of males (poculum) short, slightly pronounced, barely reaching tergum X, posterior margin rounded. Sternum VII of females with a small preopercular organ, forming a small lump-like median swelling at the posterior margin. Sternum VIII of females (subgenital plate) flat, reaching half the length of tergum IX, with the posterior margin rounded or slightly pointed. Gonapophyses VIII dorsoventrally flattened, linear to oblong, ventrally bearing setae, reaching the posterior region of tergum X. Gonoplac prominent, dorsoventrally flat, triangular, thicker and longer than both gonapophyses, ventrally bearing setae. Gonapophyses IX smooth, shiny, acute, shorter than VIII and concealed from ventral view by the enlarged gonoplac. Cerci short and small in ñ, tapered posteriorly with rounded apex, round in cross section, with third to half the length of tergum X. Cerci in ò slender, almost the same size as tergum X.

Eggs (not known for X. michaelis ): Rounded, sub cylindrical, 1.5× longer than wide, nearly round in cross section, centrally widened in dorsal view; ventral surface flat (allowing gluing to flat surfaces), polar area slightly flat. Opercular aperture angled at approximately 45° towards dorsal region. Operculum round, slightly convex, with a distinct straight stalk with an apical irregular conical projection widening towards apex. Capsule and operculum densely covered with hairy setae of different sizes. Micropylar plate usually surrounded by a lighter, whitish color. Micropylar plate creamish, varying from round to oval to sub-rectangular, glabrous, with small sparse setae, and ridged margins, occupying almost 1/3 of the egg’s length. Micropylar cup dark, wide, elliptical, continuous with the short internal median line. Internal micropylar plate opened.

Geographic distribution

( Fig. 4)

Xerosoma species are endemic to the Atlantic Forest in the southeast and northeast regions of Brazil, being recorded from six states: Sergipe, Bahia, Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo. It is expected that further sampling in other areas of the broad Atlantic Forest will increase the occurrence area of the genus. All of the gathered records comprise new or more precise occurrence records for the genus.

Figures

Fig. 3. Males of Xerosoma species, anterior region of the body in dorsal and lateral views.A: X. canaliculatum in dorsal view. B: paratype (1442) of X. nannospinus sp. nov. in dorsal view. C: X. canaliculatum in lateral view, black arrow indicating the strongly pronotal spines. D: paratype (1442) of X. nannospinus sp. nov. in lateral view, black arrow indicating the reduced pronotal spines. Scale bar = 1 cm.

Fig. 2. Females of Xerosoma species, anterior region of the body in dorsal and lateral views. A: X. canaliculatum, black arrow indicating the strongly pronotal spines. B: holotype of X. nannospinus sp. nov. (MZUSP 1440), black arrow indicating the reduced pronotal spines. C: lectotype of X. michaelis, black arrow indicating the strongly prickly ventral margin of femur and the brachypterous wings. Photographs provided by Oskar Conle, Frank Hennemann and Pablo Riquelme, published with permission. Scale bar = 2 cm.