Phyllium ouelleti Cumming, Foley, Hennemann, Le Tirant & Büscher, 2025

Cumming, Royce T., Foley, Evelyn Marie, Hennemann, Frank H., Le Tirant, Stephane, Daawia,, Warikar, Evie Lilly, Yando, Heron, Suhartawan, Bambang, Henze, Katharina, Büscher, Thies H. & Bank, Sarah, 2025, A deeper look into the diversity of Phyllium leaf insects from Indonesia: seven new species and two unique egg morphologies (Phasmatodea, Phylliidae), ZooKeys 1256, pp. 317-370 : 317-370

Phyllium ouelleti Cumming, Foley, Hennemann, Le Tirant & Büscher sp. nov.

Fig. 17

Type material.

Holotype ( ♀): Indonesia, North Maluku, Obi Island ; VII-2021 [ IMQC].

Differentiation.

Presently only the female is known. The female Phyllium ouelleti sp. nov. is morphologically most similar to Phyllium tobeloense due to general femoral lobe shape / spination, coxae coloration, and overall body shape / size. The tegmina length and venation allows differentiation of these two species, as Phyllium ouelleti sp. nov. has longer tegmina, reaching the anterior margin of abdominal segment IX while Phyllium tobeloense has them only reaching onto segments VII or VIII. Likely due to the longer tegmina, there is also a difference in the venation as the media (M) is trifurcate in Phyllium ouelleti sp. nov. but bifurcate in Phyllium tobeloense . Also, these two species can be differentiated by the mesoprescutum surface area, as Phyllium ouelleti sp. nov. has a smaller surface due to a wider membranous attachment area of the forewings (vs Phyllium tobeloense which has smaller forewing attachment membranous areas, allowing the mesoprescutum to reach further back posteriorly). This membranous tegmina attachment area in Phyllium ouelleti sp. nov. also shortens the mesoprescutum lateral margins, resulting in the tubercles along these margins to be more tightly packed (Fig. 17 F ), vs in Phyllium tobeloense where they are slightly more spread out. Additionally, the mesopleurae lateral margin differs slightly, as Phyllium ouelleti sp. nov. has the margin nearly perfectly straight (Fig. 17 F ), vs Phyllium tobeloense which has them angled slightly more prominently inward towards the anterior, resulting in a slight bend on the anterior end. The tegmina length also differs as Phyllium tobeloense has shorter tegmina, only reaching to the anterior margin of abdominal tergite VIII or slightly onto it, but Phyllium ouelleti sp. nov. has tegmina which reach the anterior margin of tergite IX (Fig. 17 A ).

Description.

Female. Coloration. Coloration description is based upon the dead, dried holotype specimen (Fig. 17 ). Unfortunately, the holotype appears to have not been dried very well, and has many dark, discolored areas. Some coloration that can be seen is that the mesocoxae and metacoxae differ in color, with the mesocoxae a similar color to the surrounding tissue, while the metacoxae appear to have a dark spot, similar to Phyllium tobeloense but not quite as crisply edged as in that species. Additionally, the profemoral interior lobes and protibiae interior lobes appear to have some orange striping, a feature which is known from several Phyllium species, but is often variable in its intensity or completely absent in some individuals.

Morphology. Head capsule is longer than wide, with a vertex that is relatively smooth except for a singularly pointed posteromedial tubercle which is not very large (Fig. 17 F ). Frontal convexity broad and ending in a relatively fine point; surfaces smooth except for a few short setae. Compound eyes only slightly protruding from the head capsule, not overly large, taking up ~ ¼ of the head capsule lateral margins (Fig. 17 F ). Ocelli absent. Antennal field slightly wider than the first antennomere.

Antennae consist of nine segments, with the terminal segment approx. the same length as the preceding two segments’ lengths combined (Fig. 17 B ). Antennomeres I – VII smooth but sparsely marked with small transparent setae, the terminal two antennomeres are covered in dense, short setae giving them a fuzzy appearance (Fig. 17 B ).

Thorax. Pronotum with slight concave anterior margin and straight lateral margins, which converge to the posterior margin that is ½ the width of the anterior margin (Fig. 17 F ). The pronotum surface is relatively smooth, with only a prominent pit in the center and a sagittal furrow on the anterior 1 / 2 (Fig. 17 F ). The pronotum has a distinctly formed anterior rim, moderately formed lateral rims, and a weakly formed posterior rim (Fig. 17 F ). Prosternum, mesosternum, and metanotum have nodes running along the sagittal plane, with the lateral margins relatively smooth, lacking nodes. Mesoprescutum approx. as long as wide, lateral rims with four tubercles and one or two smaller nodes interspersed (Fig. 17 F ). The tegmina membranous attachment areas are large and encroach on the mesoprescutum lateral margins, shortening them and compressing the tubercles somewhat (Fig. 17 F ). Mesoprescutum anterior rim prominent and raised into a blunted sagittal spine; the mesoprescutum rim surface is slightly lumpy (Fig. 17 D ). Mesoprescutum raised slightly along the sagittal crest, which is marked with three small nodes, while the remainder of the surface is smooth (Fig. 17 F ). Mesopleurae begin near the anterior rim, have straight margins, and run uniformly diverging throughout their lengths (Fig. 17 F ). Mesopleurae lateral margins with five or six moderately sized tubercles with minimal granulation between a few of the larger ones (Fig. 17 F ). Face of the mesopleura smooth or slightly wrinkled, with two notable divots, one on the anterior 1 / 3 and one less prominent one slightly posterior to the middle (Fig. 17 F ).

Wings. Tegmina long, reaching the anterior margin of abdominal segment IX. Tegmina venation; the subcosta ( Sc) is the first vein in the forewing, running parallel with the margin for the first 1 / 2, and then bending and running towards the margin where it terminates 1 / 3 of the way through the wing length. The radius (R) spans the central portion of the forewing with two subparallel branched veins; the first radius ( R 1) branches ~ 1 / 5 of the way through the wing length and terminates slightly proximal to the midline, and the radial sector ( Rs) branches ~ 1 / 3 of the way through the wing length and terminates near the distal 1 / 3 of the wing length. There is a weak continuation of the radius following the prominent Rs branching which continues on as a short and thin R – M crossvein that does not appear to actually connect the two veins. The media (M) is trifurcate with a media anterior ( MA; originating near the middle of the tegmina length and terminating on the distal 1 / 5), first media posterior ( MP 1; originating on the distal 1 / 3 of the tegmina length and terminating near the apex), and a second media posterior ( MP 2; which is small, originates near the distal 1 / 5 of the tegmina length and terminates near the tegmina apex). The cubitus ( Cu) is also bifurcate, branching near the posterior 1 ⁄ 10 of the wing into the cubitus anterior ( CuA) and cubitus posterior ( CuP) which both terminate at the wing apex. The first anal vein ( 1 A) is simple and fuses with the cubitus early on, ~ ¼ of the way through the tegmina length. Alae vestigial.

Abdomen. Abdominal segments II through the anterior 2 / 3 of IV uniformly diverging. The posterior 1 / 3 of segment IV through segment VII are converging, with the degree of convergence slightly increasing from IV through VII. The posterior 1 / 3 of segment VIII ends in a slightly rounded lobe. Segments IX and X are notably narrower than the previous segments, and have straight, converging margins to the broad rounded apex.

Genitalia. Subgenital plate starts at the anterior margin of tergum VIII, is moderately broad, and extends halfway onto tergum X with straight margins ending in a fine point (Fig. 17 G ). Gonapophyses VIII are long and moderately broad, reaching the apex of abdominal tergum X; gonapophyses IX are shorter and narrower, hidden below gonapophyses VIII (Fig. 17 G ). Cerci flat, somewhat rectangular, with a slightly rough textured surface (Fig. 17 G ).

Legs. Profemoral exterior lobe smoothly arching from end to end, ~ 3 × wider than the width of the profemoral shaft greatest width (Fig. 17 C ). Edge of the profemoral exterior lobe smooth and unadorned (Fig. 17 C ). Profemoral interior lobe as wide as the exterior lobe, approximately right angled, and marked with six teeth (four large and two small) arranged in a small-large-large-small-large-large pattern, with looping gaps between the teeth (Fig. 17 C ). Mesofemoral exterior lobe roughly a narrow, rounded triangle with the greatest width only slightly wider than the mesofemoral shaft width, and the greatest width situated on the distal 1 / 3 of the mesofemora. Just distal to the mesofemoral exterior lobe greatest width is a singular, small tooth. Mesofemoral interior lobe is approx. the same width as the mesofemoral shaft, and is similar to the exterior lobe with the greatest width on the distal 1 / 3, but the interior lobe is slightly more rounded, not as straight edged as the exterior lobe. Mesofemoral interior lobe distal 1 / 2 is also marked by six or seven small, distally pointing, serrate teeth. Metafemoral interior lobe arcs end to end, with the distal 1 / 2 slightly wider than the proximal 1 / 2 and marked with nine serrated teeth on the distal 1 / 2 of the lobe. Metafemoral exterior lobe is thin and smooth, hugging the metafemoral shaft and lacks dentation. Protibia lacking an exterior lobe (Fig. 17 C ). Protibia interior lobe spans the entire length of the protibia and is ~ 2 × the width of the protibia shaft itself. The lobe is roundly triangular with the widest portion on the distal 1 / 2. Mesotibiae and metatibiae simple, lacking exterior and interior lobes.

Measurements (mm). Holotype, female: body length (including cerci and head, excluding antennae): 93.5, length / width of head: 10.5 / 8.1, antennae: 5.3, pronotum: 6.7, mesonotum: 7.8, length of tegmina: 62.6, greatest width of abdomen: 37.0, profemora: 18.8, mesofemora: 16.5, metafemora: 22.7, protibia: 11.3, mesotibia: 11.7, metatibia: 17.8.

Etymology.

Patronym, named after Pierre-Olivier Ouellet, who donated the specimen to the IMQC.

Distribution.

At present only known from Obi Island, Indonesia (Fig. 2 ).

Remarks.

Despite Obi being a relatively small island (ca 2,542 km 2), this new species represents the second species of leaf insect known from Obi Island, the first being Comptaphyllium regina ( Cumming et al. 2019 b) . Morphologically this species is most similar to Phyllium tobeloense and likely represents a closely related species. Unfortunately, the holotype Phyllium ouelleti sp. nov. is somewhat degraded and was therefore not included in our molecular phylogeny to confirm this relationship.

Figures

Figure 2. Distribution map for all Phyllium species used in the molecular analysis as well as the newly described species from Obi Island not represented in the phylogenetic tree. Species names of Phyllium from Malaysia, the Philippine Islands, and New Britain (Papua New Guinea) are shown in gray. The Indonesian archipelagic state is highlighted in blue and symbols of sampling sites of Indonesian Phyllium species are in dark blue. White symbols show the location of the remaining Phyllium from Malaysia, the Philippine Islands and New Britain (Papua New Guinea). The inset presents an enlarged section of Sabah (Malaysia: Borneo) and the six species found there. Abbreviations: Hal, Halmahera; Jav, Java; Kal, Kalimantan; NG, New Guinea (Papua); Ser, Seram; Sul, Sulawesi; Sum, Sumatra.

Figure 17. Phyllium ouelleti sp. nov. holotype female (IMQC). A. Habitus, dorsal; B. Details of antennae, dorsal; C. Detail of front right leg, dorsal; D. Thorax, lateral (head to the right); E. Habitus, ventral; F. Details of the antennae, head, and thorax, dorsal; G. Terminalia, ventral. Scale bars: 20.0 mm (A); 5.0 mm (B); 10 mm (C); 20.0 mm (E); 10.0 mm (F).