Phyllium (Phyllium) nisus, Cumming & Bank & Le Tirant & Bradler, 2020

Cumming, Royce T., Bank, Sarah, Le Tirant, Stephane & Bradler, Sven, 2020, Notes on the leaf insects of the genus Phyllium of Sumatra and Java, Indonesia, including the description of two new species with purple coxae (Phasmatodea, Phylliidae), ZooKeys 913, pp. 89-126 : 89

Phyllium (Phyllium) nisus sp. nov. Figures 7A-E , 8A-E , 9C-D , 10A , 13A

Type material.

Holotype: ♀, Indonesia: Sumatra, Bengkulu Prov., Bengkulu District, Besuki Village: IV.2017, Local Collector. Deposited in the Montreal Insectarium type collection (Coll RC 18-157) (Figure 13A ). Paratypes: of 128 ♀♀, 36 ♂♂, and 39 eggs are deposited in the collections of Royce T. Cumming, Stephane Le Tirant, Oskar V. Conle, the Bogor Zoology Museum, and the Montreal Insectarium (see Suppl. material 3: Table S3 for details).

Discussion.

This population has been available within the phasmid breeding community for a number of years under the name Phyllium sp. "Bukit Daun" and has been noted as a reasonably easy species to breed in captivity (Figures 7A-E , 8A-E ).

This population has already undergone extensive morphological scrutiny in Cumming et al. (2018) where no significant morphological features were identified between the Peninsular Malaysia and Sumatran populations to allow visual separation based on adults alone. The only consistent visible feature between the two populations is the color of the eggs, with Phyllium hausleithneri from Peninsular Malaysia having dark brown eggs (Figure 9A, B ) and Phyllium nisus sp. nov. with pale tan eggs (Figure 9C, D ). The only closely related species which can consistently be morphologically separated is Phyllium jacobsoni by coxae color (white in P. jacobsoni , Figure 5C, D , and purple in P. nisus sp. nov., Figures 7B , 8D ). Newly hatched nymphs of P. nisus sp. nov. (Figure 8E ) cannot be differentiated from the dark form of P. jacobsoni or the average P. hausleithneri nymphs, and their identical morphology helps to illustrate their shared common ancestry.

Phyllium nisus sp. nov. is possibly the species referred to in Klante (1976) from Sumatra, which he erroneously attributed to Phyllium woodi Rehn & Rehn, 1934. The specimen he examined was rather large at 79.0 mm, which falls within the observed range of Phyllium nisus sp. nov. (see Table 1 ), and, based on the prominent profemoral interior lobe teeth, this specimen could be a large major form of Phyllium nisus sp. nov. female. However, without examining this specimen in person we are not confident in attributing this specimen to Phyllium nisus sp. nov. due to the cryptic nature of congenerics and therefore must leave this historic record at speculation. For full morphological measurements see Suppl. material 3: Table S3. Fortunately, a sizeable series of bred paratype specimens were examined thus allowing adequate description of the average adults and egg coloration. Coloration of the overall body was rather variable as discussed below, but the coxae and egg coloration showed little variation between individuals and we consider these colors as a reliable feature for differentiation.

Description.

Female. Coloration. Individuals are always a vibrant pale green with varying degrees of reddish or grayish brown coloration on specific regions of the body (Figures 1B , 7A ). On the lightest colored individuals, no brown markings are present, with even the antennae a pale color similar to the shade of green on the head capsule (see the holotype female in Figure 13A for an example of a female without brown markings). In individuals which are more colored, the areas which are most frequently with these brown markings are the antennae, frontal convexity, protibiae, profemoral interior lobe, prescutum, mesopleurae (Figure 7C ), small interior patches of brown on the tegmina, and the terminal abdominal segments VII-X margins (Figure 7A ). On intermediate colored individuals, these features can be a third to half colored with brown, and in darker individuals these features are always at least half colored with some features almost completely colored with brown. Compound eyes are generally paler than the head capsule and usually of a yellow coloration with slight tan striping (Figure 7A ). Meso- and metacoxae ventrally always with a dark blue to purple coloration which is only visible when the legs are bent forward (Figure 7B ).

Morphology. Head. Head capsule about as long as wide, vertex with granulation throughout the surface, some more closely spaced than others (Figure 7C ). The posteromedial tubercle is broader and taller than any other nodes, on the head. Frontal convexity broad and about as long as the first antennomere, and with slight granulation on the dorsal surface and several setae present which are longer than any setae on the antennae. Compound eyes only slightly protruding from the head capsule, but are significantly large, taking up about one fourth of the length of the lateral head capsule margins (Figure 7C ). Ocelli absent. Antennal fields slightly wider than and about as long as the length of the first antennomere. Antennae. Antennae consisting of nine segments, with the terminal segment about the same length as the preceding two segments’ lengths combined (Figure 7C ). Antennomeres I-VII sparsely marked with small transparent setae, the terminal two antennomeres are covered in stout, brown setae. The pars stridens of antennomere III has 37-44 teeth. Thorax. Pronotum with gently concave anterior margin and nearly straight lateral margins, which converge to a straight posterior margin that is half the width of the anterior margin (Figure 7C ). Pronotum anterior margin with small lateral defensive spray gland openings (no detectable defensive spray has been noted for these while in breeding however). The pronotum surface is marked with only minimal small granulation, with only a prominent pit in the center, and slight furrows anterior and lateral to the pit (Figure 7C ). The pronotum has a prominent anterior rim and weakly formed lateral and posterior rims, all of which have only slight granulation (Figure 7C ). Prosternum and the mesosternum with stout and numerous nodes, those on the anterior half of the mesosternum on the sagittal plane are slightly larger than those on the prosternum. Metasternum with short granulation throughout the entire surface. Prescutum as long as wide or occasionally slightly longer than wide, but never wider than long (Figure 7C ). Lateral rims with nine to eleven lumpy node-like tubercles ranging in size from small to medium with small granulation present throughout the length interspersed with the tubercles (Figure 7C ). Prescutum anterior rim prominent but not strongly protruding, with a distinct singular tubercle with the remainder of the rim relatively smooth (Figure 7C ). Prescutum crest (excluding the tubercle of the anterior rim) with four to five distinct but not large nodes evenly spaced and nearly uniform in size, or with the anterior most node slightly larger than the rest. The Prescutum crest is not prominently protruding because the smooth surface of the Prescutum rises up to it, making the crest not much more than the nodes along the sagittal plane (Figure 7C ). Mesopleurae beginning near the anterior margin of the Prescutum and evenly diverging; lateral margin with eight to eleven tubercles which are largest on the anterior end and steadily decreasing in size as they reach the posterior, eventually no larger than nodes (Figure 7C ). Some of the largest tubercles have slightly granular surfaces or granulation at the base. Face of the mesopleurae with granulation throughout, and with two notable divots, one on the anterior third and one nearer the posterior third (Figure 7C ). Wings. Tegmina length variable, ranging in length from halfway through abdominal segment VII to at most reaching about three quarters of the way into segment VIII. Tegmina venation is rather stable between individuals (Figure 10A ). The subcosta (Sc) is the first vein in the forewing and bends inward away from the anterior margin. The radius (R) spans the central portion of the forewing with two subparallel branched veins; radius 1 (R1) terminates anterior to the widest medial expansion of the tegmina, and the radial sector (Rs) terminates posterior to the widest medial expansion, therefore the R1 and Rs occupy the majority of the center of the wing. There is a weak continuation of the radius following the prominent Rs branching which continues on as a short and thinner R-M crossvein that does not appear to solidly connect the two veins fading as it reaches the media. The media (M) is simply bifurcate with both the media anterior (MA) and media posterior (MP) terminating close to the posterior fourth of the wing. The cubitus (Cu) is also bifurcate, branching near the posterior fifth of the wing into the cubitus anterior (CuA) and cubitus posterior (CuP) which both terminate at or very near the wing posterior apex. The first anal vein (1A) is simple and fuses with the cubitus early on, only slightly past the branching distance of the R1 from R (Figure 10A ). Alae rudimentary, only about 4.0 mm in length (Figure 7D ). Abdomen. Abdominal shape quite variable, with the only consistent feature being segments II through the anterior two thirds of IV diverging, with the posterior third of segment IV the widest segment. Segments V through VIII are variable and can have perfectly straight margins (giving the abdomen a smooth spade shaped appearance, similar to the holotype female in Figure 13A ) or strongly lobed margins (like in Figure 1B ). Between these two extremes there are all possible forms/degrees of lobed margins with the forms continuous, not discrete. Segments IX and X are notably narrower than the previous segments and converge uniformly without lobes to the rounded apex. Genitalia. Subgenital plate starts at the anterior margin of segment VIII, is broad, and extends halfway to three quarters into segment X, ending in a fine point (Figure 7E ). Gonapophyses are long and slender, reaching or very slightly exceeding the apex of abdominal segment X (Figure 7E ). Cerci flat, not strongly cupped, with a granular surface and few detectable setae (Figure 7E ). Legs. Profemoral exterior lobes narrow and smoothly arcing from end to end without a strongly notable angle, narrower than the width of the interior lobe (Figure 7C ). Edge of the profemoral exterior lobe smooth without notable granulation or teeth (Figure 7C ). Profemoral interior lobe wider than the exterior and with a right angle or slightly obtuse angle and marked with four to five teeth (Figure 7C ). These teeth have a slightly wider gap in the center, and are variable in size ranging from small serrate teeth to larger angular teeth (Figure 7C ). Generally, the size of the teeth is paralleled by the size of the abdominal lobes but not always. Mesofemoral exterior lobe arcs from end to end but is slightly weighted towards the distal half and marked with one to three small serrate teeth distributed on the distal half only. Interior and exterior lobes can be of similar width, or interior lobe can be slightly thinner. Mesofemoral interior lobe arcs end to end with five to six small serrate teeth only on the distal half of the arc which is slightly wider than the proximal half of the arc. Metafemoral interior lobe arcs end to end and has five to six serrate teeth on the distal half of the lobe. Metafemoral exterior lobe is thin and smooth, hugging the metafemoral shaft and generally with no teeth but occasionally with one to two at the distal most edge. Protibiae lacking an exterior lobe. Protibiae interior lobe spans the entire length of the protibiae and can be one and a half to two times the width of the protibiae shaft itself. The lobe is distinctly triangular and can be nearly evenly distributed or slightly wider on the distal half. Mesotibiae and metatibiae lacking exterior and interior lobes.

Male. Coloration. Overall coloration pale green throughout with variable patches of brown to reddish coloration (Figure 8A ). Compound eyes are generally paler than the head capsule and of a yellow coloration with slight tan striping (Figure 8B ). The antennae are darker in color, with each segment exhibiting a slight green in addition to brown towards the apex of each segment, which gives the antennae an overall striped appearance of green and brown (Figure 8B ). Males can be completely green lacking any brown coloration except slight brown markings on the protibial interior lobe, or they can range to the other extreme with brown markings on protibial, profemoral, and mesofemoral lobes along with the margins of the metafemoral lobes and the margin of the abdomen (Figure 8A ). Meso- and metacoxae ventrally with a pale to dark purple and white coloration (Figure 8D ). The coloration on the mesocoxae is generally darker and easier to distinguish than the purple on the metacoxae, which is only a faint purple hue on a mostly white surface.

Morphology. Head. Head capsule longer than wide, with a vertex that is nearly completely smooth or in some individuals there can be two or three small nodes near the posteromedial tubercle (Figure 8B ). Frontal convexity stout with sparse thin setae. The posteromedial tubercle is not broad but is distinctly raised from the head capsule. Compound eyes large and bulbous, taking up over one third of the head capsule lateral margins (Figure 8B ). Three ocelli moderately developed located between and slightly posterior to the compound eyes. Antennal fields as wide and as long as the scapus. Antennae. Antennae (including the scapus and pedicellus) consists of 23 segments, all segments except the scapus and pedicellus and terminal four segments are covered in dense setae that are as long as or longer than the antennae segment is wide. The terminal four segments are covered in dense short setae and the scapus and pedicellus are nearly completely bare. Thorax. Pronotum with anterior margin distinctly concave and lateral margins that are slightly convex and converging to a straight posterior margin that is slightly more than half the width of the anterior rim (Figure 8B ). Anterior margin of the pronotum has a distinct rim, lateral margins have moderate rims, and the posterior margin lacks a rim (Figure 8B ). Face of the pronotum is marked by a distinct furrow and pit in the center, a smooth surface, and three distinct pits along the anterior margin (Figure 8B ). Prosternum is granulose throughout with small nodes of even size and spacing. Mesosternum surface marked with more prominent nodes, with the largest along the sagittal plane and more strongly on the anterior margin, posterior margin with less prominent and small nodes. Prescutum longer than wide, with lateral margins slightly converging to the posterior (Figure 8B ). Lateral rims with eight to nine tubercles of varying size, some prominent but others rather small and not much more prominent than nodes (Figure 8B ). Prescutum crest along the sagittal plane with four to five small nodes of uniform size and spaced throughout the length. The surface of the prescutum rises up to meet the crest with a face that is smooth (Figure 8B ). Prescutum anterior margin marked with a tubercle, which is only about two times larger than any of the other nodes along the crest. Mesopleurae not notably wide and diverge almost uniformly along the entire length, diverging slightly more prominently at the posterior margin (Figure 8B ). Lateral margin with four to five major tubercles throughout the length, and between six and nine smaller minor tubercles interspersed throughout. Each tubercle is marked by either a single stiff, short setae or with as many as three setae. Face of the mesopleurae slightly wrinkled and with two faint divots, one on the anterior third and one on the posterior third. Tegmina moderate length, extending halfway to three quarters the way through abdominal segment III. Wings. Tegmina wing venation (see Figure 10B for general venation found in the species of this clade): the subcosta (Sc) is the first vein and terminates the earliest, about one third of the way through the overall tegmina length. The radius (R) spans the entire length of the tegmina with the radius 1 (R1) branching just anterior to the middle and terminating just posterior to the middle of the wing with the radial sector (Rs) terminating nearly at the wing apex. The media (M) also spans the entire length of the tegmina with the media posterior (MP) branching off slightly posterior to the middle and terminating promptly. The cubitus (Cu) terminates past the midline upon meeting the media posterior. The first anal (1A) vein terminates upon reaching the cubitus near the midline. Alae well developed in an oval fan configuration, long, reaching to the anterior margin of abdominal segments IX or X. Alae wing venation (see Figure 10B for general venation found in the species of this clade): the costa (C) is present along the entire foremargin giving stability to the wing. The subcosta (Sc) is short, spanning less than a third of the wing length and is mostly fused with the radius in the beginning but terminates when it meets the costa. The radius (R) spans the entire wing and branches approximately a third of the way through into the radius 1 (R1) and radial sector (Rs) which run nearly parallel through most of their length until they terminate at the wing apex near each other but not touching. The media (M) branches early (only about a sixth of the way through the wing into the media anterior (MA) and the media posterior (MP) which run parallel with each other throughout the central two thirds of the wing until the media posterior fuses with the media anterior which eventually fuses with the above radial sector about one sixth of the way from the wing apex. 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 near the point where the media branches into the media anterior and media posterior and then the first anterior anal branches from the cubitus three fifths 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 two through seven (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-5PA) 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. Abdominal segments II slightly converging, III through the anterior two thirds of segment IV diverging to the widest portion. The posterior of IV through V either almost parallel sided or converging, and segment VI through X uniformly converging (Figure 8A ). Genitalia. Poculum broad, and ends in a straight margined apex that slightly passes the anterior margin of segment X (Figure 8C ). Cerci long and slender, extending from under the anal abdominal segment, slightly cupped, covered in a granulose surface and numerous short setae (Figure 8C ). Vomer broad and stout with straight sides evenly converging, and a thick single apical hook which hooks upwards into the paraproct (Figure 8C ). Legs. Profemoral exterior lobe one third to two thirds the width of the interior lobe, hugging the curve of the profemoral shaft and marked with a granular margin and fine small setae but no notable teeth (Figure 8B ). Profemoral interior lobe roundly triangular and marked with five teeth which can be small and serrate or larger and triangular in more prominent individuals (Figure 8B ). Mesofemoral exterior lobe arcs end to end, but is significantly weighted on the distal half which is marked with one to two serrate teeth, and the proximal half that is rather thin. Mesofemoral interior lobe is slightly thinner than the exterior lobe, is broader on the distal end and is marked with five to six small serrate teeth. Metafemoral exterior lobe lacks dentition, and has a straight margin along the metafemoral shaft. Metafemoral interior lobe smoothly arcs end to end with seven to eight small serrate teeth on the distal half. Protibiae lacking exterior lobe, interior lobe reaching end to end in a smooth evenly weighted triangle only one to one and a half times as wide as the protibial shaft (Figure 8B ). Meso- and metatibiae simple, lacking lobes completely.

Eggs.

The lateral surfaces are flattened and the dorsal surface is slightly convex, which gives the egg a slight bend (Figure 9C, D ). When viewed from the lateral aspect, the anterior width of the capsule is the narrowest, with the width slightly increasing steadily to the posterior, but only slightly so (Figure 9C ). When viewed from the lateral aspect, the dorsal margin has long feather-like pinnae with single or double branching tips along almost the entire length with occasionally some individuals with the anterior most area lacking these long pinnae, the posterior margin also has these long pinnae (Figure 9C ). The ventral margin lacks these long feather-like pinnae on the edges, but instead has a row of slightly shorter pinnae along the posterior half of the ventral surface sagittal plane with those at the posterior the largest followed by pinnae steadily decreasing in length as they reach the anterior which lacks these sagittal pinnae (Figure 9C ). Lateral surfaces with three rows of bald impressions, with the space between densely covered with short carpet-like pinnae (Figure 9C ). These three rows of impressions are variable between individuals, but the most common is that the three bald rows are continuous, not broken into smaller bald impressions, however, some individuals have been observed as having the bald impressions slightly broken up into smaller portions. Micropylar plate ranging from two thirds to four fifths of the overall dorsal surface length, with the thickest portion the center or slightly off center towards the micropylar cup (Figure 9D ). Micropylar plate teardrop shaped, with most of the width as wide as the micropylar cup (Figure 9D ). Micropylar cup of moderate size and placed on the posterior quarter of the capsule (Figure 9D ). Operculum slightly ovular, with the outer margin with a row of pinnae similar to those along the posterior edge of the capsule, rarely forked, almost always with a single prominent end. Overall color light tan (Figure 9C, D ).

Measurements including the extended pinnae [mm]. Length (including operculum) 6.2-6.5 mm, maximum width of capsule when viewed from lateral aspect 3.6-3.8 mm, length of micropylar plate 2.5-2.6 mm.

Newly hatched nymphs.

General color throughout the body (including head and antennae) is dark brown to black (Figure 8E ). Margins of the abdomen are white. Meso- and metafemora with a continuous transverse white band on the proximal third; a small white spot on the interior lobe proximal margin; and a thin white crescent on the distal exterior lobe margin. Profemora dark brown to black, except for near the proximal third where there can be small white spots on each side of the profemoral shaft, but not a solid transverse white band. Tibiae on all legs the same dark brown to black as the rest of the body but with faint two to three tan spots on all of the interior margins on the proximal third, or more clearly white than tan on the protibial interior lobe. Basitarsi are white and remaining tarsal segments are tan to dark brown.

Etymology.

Noun, Greek in origin, Νῖσος. Named after Nisus, king of Megara, who had a single purple lock of hair that, for as long as it was not cut, guaranteed him life and possession of his kingdom. We felt that this homage was fitting to the purple-haired king as this species has the singular purple feature (coxae) which is unique among the Phylliidae with only the species in this clade known to have purple coxae.

Figures

Figure 1. Three female Phyllium with purple coxae, dorsal. Bred by Tim Van molle (Rupelmonde, Belgium). A Phyllium hausleithneri " Tapah, Perak Malaysia " B Phyllium nisus sp. nov. " Bukit Daun, Sumatra, Indonesia " C Phyllium gardabagusi sp. nov. " Argopuro, Java, Indonesia ".

Figure 2. Maximum likelihood tree of 18 Phyllium specimens from Java and Sumatra and three outgroup species. The phylogenetic tree was generated with IQ-TREE and rooted with Orthomeria kangi (Aschiphasmatinae). Ultrafast Bootstrap support values are given below nodes. Lineages with short branch lengths were collapsed. A and B depict the two main Phyllium clades. Purple circles indicate those species with purple colored coxae.

Figure 5. Phyllium jacobsoni live captive bred individuals, photos courtesy of Bruno Kneubuehler. A Female B male C male ventral view of coxae D female ventral view of coxae E freshly hatched nymph.

Figure 7. Female Phyllium nisus sp. nov. live captive bred individuals, photos courtesy of Bruno Kneubuehler. A dorsal view B ventral view of purple coxae C dorsal head and thorax details D tegmina held open to show exposed underdeveloped alae E ventral genitalia details.

Figure 8. Male Phyllium nisus sp. nov. live captive bred individuals, photos courtesy of Bruno Kneubuehler. A Dorsal view B dorsal head and thorax details C ventral genitalia details D ventral view of purple coxae E freshly hatched nymph.

Figure 9. Eggs from the four species in clade B. A Phyllium hausleithneri, lateral view (Coll RC 18 - 002) B micropylar plate view (Coll RC 18 - 003), note that this individual exhibits a slightly longer micropylar plate than average which makes it appear longer than the other clade members, this is simply the upper limit of the morphological variation C Phyllium nisus sp. nov., lateral view (Coll RC 17 - 380) D micropylar plate view (Coll RC 17 - 377) E Phyllium gardabagusi sp. nov., lateral view F micropylar plate view G Phyllium jacobsoni, lateral view H micropylar plate view. Photos E-H courtesy of Bruno Kneubuehler.

Figure 10. Representative female and male tegmina and alae wing venation present in our molecularly identified Clade B (see Figure 2), which is present in the new species Phyllium gardabagusi sp. nov. and Phyllium nisus sp. nov. A Female tegmina illustrated here is a Phyllium nisus sp. nov. (Coll RC 17 - 107) B male tegmina and alae illustrated here is a Phyllium hausleithneri (Coll RC 16 - 087). Abbreviations used: C (costa); Sc (subcosta); R (radius); R 1 (radius 1); Rs (radial sector); R - M (radius and medial crossvein); M (media); MA (media anterior); MP (media posterior); Cu (cubitus); CuA (cubitus anterior); CuP (cubitus posterior); Cu + 1 AA (cubitus and first anterior anal); 1 A (first anal); 1 AA- 7 AA (first through seventh anterior anal); 1 PA- 5 PA (first through fifth posterior anal).

Figure 13. Holotypes for the two new Phyllium species described herein. A Phyllium (Phyllium) nisus sp. nov. from Sumatra, Indonesia B Phyllium (Phyllium) gardabagusi sp. nov. from Java, Indonesia.