Phyllium iyadaon sp. nov.

Cumming, Royce T., Le Tirant, Ste ́ phane, Linde, Jackson B., Solan, Megan E., Foley, Evelyn Marie, Eulin, Norman Enrico C., Lavado, Ramon, Whiting, Michael F., Bradler, Sven & Bank, Sarah, 2023, On seven undescribed leaf insect species revealed within the recent " Tree of Leaves " (Phasmatodea, Phylliidae), ZooKeys 1173, pp. 145-229 : 145

Phyllium iyadaon sp. nov.

Fig. 9

Material examined.

Holotype ♂: " Philippines: Mindoro, Puerto Galera: April, 2017; Coll RC 17-221". Deposited in the Montreal Insectarium, Quebec, Canada (IMQC) . Paratype: (1♂) • " Philippines: Mindoro, Puerto Galera: April, 2017; Coll RC 17-222" (Coll RC) .

Differentiation.

Female, freshly hatched nymph, and egg unknown. Males morphologically are similar to Phyllium philippinicum and Phyllium bourquei in all features except for the undulating abdomen, the profemoral interior lobe with a notable space between the third and fourth tooth, and the sagittal crest of the mesonotum differs by having a prominent anterior spine with the remainder of the sagittal crest having weakly formed tubercles (Fig. 9E, F ).

Male. Coloration. Coloration description based on the dried type specimens. Coloration is pale green with variable areas of straw yellow throughout likely due to the drying process, particularly if alcohol was used to help preserve the specimens (Fig. 9 ). Compound eyes are burnt red (Fig. 9B ) and the anterior seven or eight segments of the antennae are darker green than the other segments which are a similar off-yellow color like the discolored patches on the body (Fig. 9C ). All abdominal segments are of a similar color, lacking eye spots.

Morphology. Head. Head capsule ca ¼ longer than wide, with a vertex that is slightly lumpy, but smooth, lacking distinct granulation; posteromedial tubercle is not prominent, only slightly raised above the head capsule (Fig. 9B ). Frontal convexities stout, only slightly projecting with blunt rounded apexes. Compound eyes are large and bulbous, occupying slightly < ½ of the head capsule lateral margins (Fig. 9B ). Between and slightly posterior to the compound eyes are three moderately formed ocelli (Fig. 9B ). Antennal fields are slightly wider than the scapus width. Antennae. Antennae (including the scapus and pedicellus) consists of 25 segments. The scapus and pedicellus are smooth, lacking setae, all other segments are covered evenly in thin, dark setae which in most cases are as long as or slightly longer than the antennal segment is wide. The terminal four antennal segments have short, dense setae, which are more numerous than the setae on the other segments. Thorax. Pronotum rectangular in shape, with a length that is ⅕ longer than the width (Fig. 9B ). Pronotum anterior margin slightly concave; lateral margins are nearly straight for the anterior ¾ of their length but then converge slightly for their remainder to a straight posterior margin that is ca ¾ the width of the anterior rim (Fig. 9B ). Anterior and lateral margins of the pronotum with distinct rims and the posterior margin with a moderately formed rim (Fig. 9B ). Face of the pronotum is marked by a relatively smooth surface (only slightly wrinkled in places and lacking distinct nodes). Face of the pronotum has a distinct sagittal furrow, a notable central pit, a moderately formed perpendicular furrow just anterior to the central pit, and two distinct pits along the anterior margin behind the anterior rim (Fig. 9B ). Prosternum with distinct and numerous granulations throughout, evenly spaced. Mesosternum anterior surface and sagittal plane marked with similar granulation to the prosternum surface, followed by more prominent wrinkles and less granulation gradually to the posterior. Metasternum distinctly wrinkled on the anterior and lateral margins, posterior with granulation slightly more prominent than the granulation on the prosternum. Prescutum as long as the anterior rim is wide, with lateral margins only slightly converging to the posterior which is ca ⅙ narrower than the anterior rim width (Fig. 9B ). Lateral rims with seven to nine tubercles of varying sizes, typically five or six are larger than the others, the smallest one or two can be notably reduced but still distinct (Fig. 9B ). The surface of the prescutum is slightly lumpy but smooth with the lateral surfaces rising slightly up to meet the prescutum sagittal crest (Fig. 9B ). The prescutum crest along the sagittal plane is connected to the anterior margin spine, and slopes posteriorly from the anterior to the posterior, lacking distinct tubercles (Fig. 9E, F ). Prescutum anterior rim distinctly raised into a prominent spine rising notably above the pronotum surface (Fig. 9E, F ). Mesopleura narrow, diverging only slightly on the anterior ½, and then distinctly widening on the posterior ½ but not projecting strongly away from the body, thus giving them an overall slender appearance (Fig. 9B ). Mesopleuron lateral margin with seven to nine moderately sized tubercles situated on the anterior ⅔ of the length with the posterior ⅓ mostly bare or at most with only a slightly undulating surface or weakly formed tubercles (Fig. 9B ). Face of the mesopleuron distinctly wrinkled and with two distinct pits, one on the anterior ⅓ and one on the posterior ⅓. Wings. Tegmina moderate length, extending ca ¼ onto abdominal segment IV. Tegmen wing venation: the subcosta (Sc) is the first vein and it runs gradually to ca ⅜ of the way through the overall tegmen length and terminates on the margin. The radius (R) spans the entire length of the tegmen, running as the radial sector (Rs) straight through the center of the tegmen to the apex after the first radius (R1) branches ca ⅓ through the length of the wing and runs approximately to the posterior ⅓ margin where it terminates. The media (M) spans the entire length of the tegmen, running parallel with the radius (R) and radial sector (Rs) and terminates at the wing apex as the media anterior (MA) after the branching of a weakly formed media posterior (MP) near the middle of the tegmen which terminates slightly posterior to the tegmen midline. The cubitus (Cu) runs through the tegmen surface angled away from the media (M) for ca ⅓ of the length to the tegmen margin and then runs along the margin to near but not meeting with the apex. The first anal (1A) vein runs subparallel to the cubitus until it meets it ca ¼ of the way through the tegmen length. Alae well-developed in an oval fan configuration, reaching ca ½ through abdominal segment IX. Ala wing venation: the costa (C) is present along the entire foremargin giving stability to the wing. The subcosta (Sc) is fused with the radius for the anterior ½ and terminates when it meets the costa slightly < ½ of the way through the wing length. The radius (R) branches ca ⅓ of the way through the ala length into the first radius (R1) and radial sector (Rs) which run gradually diverging through most of their length until near the wing apex when they run parallel briefly then converge near but not touching the wing apex. The media (M) branches early, ca 1/7 of the way through the wing into the media anterior (MA) and the media posterior (MP) which run parallel with each other until the distal ¼ of the wing where the media posterior fuses with the media anterior and they run fused towards the media posterior, but do not appear to fuse with it fully, instead simply fading. The cubitus (Cu) runs unbranched and terminates at the wing apex. Of the anterior anal veins, the first anterior anal (1AA) fuses with the cubitus slightly distal to the point where the media branches into the media anterior and media posterior and then the first anterior anal branches from the cubitus ¾ of the way through the wing length where it uniformly diverges from the cubitus until it terminates at the wing margin. The anterior anal veins 2-7 (2AA-7AA) have a common origin and run unbranched in a folding fan pattern of relatively uniform spacing to the wing margin. The posterior anal veins (1PA-6PA) share a common origin separate from the anterior anal veins and run unbranched to the wing margin with slightly thinner spacing than the anterior anal veins. Abdomen. Abdomen general shape is narrow with a maximum width only ca ⅓ wide as long. Abdominal segment II parallel sided, III slightly diverging and terminating in a small spur on the posterior margin, IV-VII individually diverging and then converging to create an undulating margin, giving the abdomen a lobed appearance. Abdominal segments VIII through X converge gradually to the narrow apex. Genitalia. Poculum ovular in overall shape, broad with lateral margins exceeding the width of abdominal segment IX, ending in a straight margined apex which passes beyond the anterior margin of abdominal segment X (Fig. 9D ). Cerci long and slender, with ca ½ of their lengths extending from under abdominal segment X (Fig. 9D ). The cerci are relatively flat, not strongly cupped, and have a weakly granular surface and sparse setae throughout. Vomer broad and stout with slightly convex sides converging evenly to the apex, which is armed with a singular upwards turning hook. Legs. Profemoral exterior lobe arcing thinly through its length with a margin that is only finely granular (none prominent), with the greatest width of the lobe only slightly wider than the profemoral shaft itself, and distinctly thinner than the greatest width of the profemoral interior lobe (Fig. 9C ). Profemoral interior lobe beginning slightly proximal to ½ of the overall shaft length in a rounded scalene triangle with the shorter proximal edge lacking teeth, but the distal edge marked by teeth arranged in a three-two pattern with a gap notably wider between these sets of small, serrate, anteriorly pointing teeth (Fig. 9C ). The profemoral interior lobe is ca 2 × as wide as the profemoral shaft at its widest. Mesofemoral exterior lobe arcs end to end with the widest portion near the distal ⅓ of the length which is approximately as wide as the mesofemoral shaft at its widest, for the proximal ⅓ of the length the lobe is thin and hugging the mesofemoral shaft. The mesofemoral exterior lobe lacks teeth, only ornamented on the distal end in a singular spine. The mesofemoral interior lobe is ca the same width as the exterior lobe and is similarly weighted from end to end with the widest portion near the distal ⅓. The distal ½ is marked with five serrate teeth which begin small and increase in size towards the distal end. Metafemoral exterior lobe lacks dentition and has a smooth margin arcing thinly along the metafemoral shaft. Metafemoral interior lobe is smooth and straight on the proximal ½ but then arcs gently and is marked by six serrate, fine teeth on the distal ½. Protibia lacking exterior lobe, interior lobe reaching end to end in a thin rounded isosceles triangle slightly <2 × as wide as the protibial shaft, with the widest point near the midline (Fig. 9C ). Mesotibiae and metatibiae simple, lacking lobes completely.

Measurements of holotype male Coll RC 17-221 [mm]. Length of body (including cerci and head, excluding antennae) 50.3, length/width of head 2.8/2.9, antennae 27.3, pronotum 2.8, mesonotum 3.8, length/width of tegmina 18.4/5.6, length of alae 35.8, greatest width of abdomen 10.7, profemora 10.4, mesofemora 8.9, metafemora 11.2, protibiae 7.4, mesotibiae 7.1, metatibiae 8.5.

Measurements of paratype male Coll RC 17-222 [mm]. Length of body (including cerci and head, excluding antennae) 52.1, length/width of head 2.8/2.9, antennae damaged and missing most segments, pronotum 2.8, mesonotum 3.8, length/width of tegmina 18.6/5.7, length of alae 36.4, greatest width of abdomen 10.8, profemora 10.4, mesofemora 8.8, metafemora 11.3, protibiae 7.4, mesotibiae 7.1, metatibiae 8.6.

Etymology.

Noun, Alangan in origin, meaning "shy leaf". We wish to honor the original inhabitants of the area that this species is native to by using a language local to northern Mindoro. We choose the threatened language, Alangan, which is spoken by as few as 2,150 speakers in north-central Mindoro (according to Ethnologue: Languages of the World; ethnologue.com). The name is formed from the Alangan words iyá (meaning shy) + daon (meaning leaf; Barbian 1977). This specific epithet was chosen to reference, first, how rarely seen this species is (as it is only known from two specimens), and second, leaf insects with their excellent camouflage can reasonably be considered to be “shy” creatures, blending into their surroundings and actively avoiding detection.

Distribution.

Currently only known from the type locality Puerto Galera, Mindoro Island, Philippines.

Remarks.

Mindoro, as a smaller island, was originally thought to only have one Phyllium species present, Phyllium mindorense Hennemann, Conle, Gottardo & Bresseel, 2009, and based upon examination of multiple specimens from this island, Phyllium mindorense appears to be the most commonly collected species. However, a morphologically distinct set of males which did not match with the known male Phyllium mindorense morphology were reviewed. These specimens were included within the analyses of Bank et al. (2021) as " Phyllium sp. 4" to ascertain if they were a morphological variation of Phyllium mindorense , or a distinct, yet to be described species. Interestingly, these specimens were recovered as sister species to Phyllium philippinicum Hennemann, Conle, Gottardo & Bresseel, 2009 and Phyllium bourquei which are species from nearby Luzon.

One possible identification which was explored is that these could represent the unknown male sex of Phyllium bilobatum Gray, 1843, which unfortunately is only known from a single holotype specimen and the inexact locality of "Philippine Islands" ( Gray 1843). Based upon the phylogenetic recovery and morphological similarity to Phyllium philippinicum and Phyllium bourquei , we find it unlikely that these Mindoro males represent the opposite sex of Phyllium bilobatum (a species which appears to be more morphologically similar to Phyllium ortizi sp. nov. based upon the smaller size, prominent femoral lobes and serration, and strongly lobed abdominal segments). The size of these two Phyllium iyadaon sp. nov. type specimens (ca 50-52 mm in length) fall within the size range for Phyllium philippinicum males (49.0-56.5 mm; Hennemann et al. 2009) and given these species’ close phylogenetic relationship, it is probable that the female Phyllium iyadaon sp. nov. may be of a similar size to Phyllium philippinicum females (which range in size from 77.5-88.0 mm; Hennemann et al. 2009). The holotype female Phyllium bilobatum on the contrary is only 65.0 mm long and therefore these Phyllium iyadaon sp. nov. males are probably not the opposite sex of Phyllium bilobatum as they are presumably too large. These two Phyllium iyadaon sp. nov. male type specimens are the only representatives of this species known to us at this time and we hope that a fresh female specimen can one day be located and confirmed as the opposite sex to allow comparison with the little known Phyllium bilobatum female.

Figures

Figure 9. Phyllium iyadaon sp. nov. type specimens A-E holotype (IMQC) Coll RC 17 - 221 F paratype (Coll RC) Coll RC 17 - 222 A habitus, dorsal B details of the head through thorax, dorsal C details of the front leg, dorsal D genitalia, ventral E details of the head through thorax, lateral F details of the head through thorax, lateral. Scale bar: 20 mm (A).