Trolicaphyllium, Cumming & Tirant & Bu ̈ scher, 2021

Cumming, Royce T., Tirant, Ste ́ phane Le & Bu ̈ scher, Thies H., 2021, Resolving a century-old case of generic mistaken identity: polyphyly of Chitoniscus sensu lato resolved with the description of the endemic New Caledonia Trolicaphyllium gen. nov. (Phasmatodea, Phylliidae), ZooKeys 1055, pp. 1-41 : 1

Trolicaphyllium gen. nov.

Type species here designated.

Phyllium brachysoma Sharp, 1898.

Taxonomic hierarchy.

Due to the general phylliid morphological features, and the consistent recovery of this clade nested within the greater phylliids in molecular studies, we herein place this genus within the tribe Phylliini Brunner von Wattenwyl, 1893.

Discussion.

The selected type species for this new genus is Phyllium brachysoma Sharp, 1898 (= Trolicaphyllium brachysoma (Sharp, 1898), comb. nov.) which was the first species described and is represented by two female syntype specimens collected on Lifou Island (Fig. 22 ). With the differentiation of the various species within this genus somewhat vague due to possible morphological variability, we felt the original species from a single known exact locality was the best choice as type species.

This new genus has been confused for decades with the similarly sized Chitoniscus Stål, 1875 sensu stricto from nearby Fiji due to their superficial similarities. All molecular phylogenies which have included both Fijian and New Caledonian samples have recovered these as polyphyletic (e.g., Buckley et al. 2009; Bradler et al. 2015; Robertson et al. 2018; Forni et al. 2020; Bank et al. 2021), with the Chitoniscus sensu stricto as sister to all other extant phylliids. Within the phylliid-wide phylogeny of Bank et al. (2021) the New Caledonian clade was recovered as sister to Comptaphyllium Cumming et al. 2019b with high support. Interestingly, few morphological features link these two genera, and it appears as though based upon morphological similarity, higher level relationships among the phylliids are difficult to ascertain. Only the intra-generic relationships appeared to agree readily when reviewing molecular and morphological data ( Bank et al. 2021).

Little is presently known about the Trolicaphyllium gen. nov. ecology at the moment, as the only host plant records we have seen to date are from a Ficus sp. (recorded by Thierry Salesne; New Caledonia) and Syzygium cumini (recorded by Sylvie Cazeres (IAC); Fig. 3 ). The only additional information we have regarding the ecology of this genus are short notes gleaned from specimen labels. In particular, “rainforest” appeared on many labels within the QM collection as noted by Geoff Monteith.

Morphological differentiation from Chitoniscus sensu stricto.

Features which liken these two genera together are their short length (ca. 40 to 60 mm) and broad bodies. Both genera have species which have smooth/tapered abdominal shapes or can be strongly lobed (within both males and females). The eggs of both species are small and lack pinnae therefore they superficially resemble each other.

However, when the finer details of these two genera are reviewed, the differences between them are significant (Table 1 ). A key to genera is not presented here as a thorough key was published within Bank et al. (2021) to all phylliid genera and can still be used to key to the Chitoniscus sensu lato couplet, at which point the features within Table 1 can then be used to differentiate these genera.

Autapomorphic features.

Several morphological features unite the New Caledonian species and support monophyly of this clade within the phylliids. Within females, the euplantula 2 and 3 on the tarsus has the unique feature of a ridge-like expansion running along the entire tarsomere (Fig. 12B ), a feature not seen in any other phylliids. Within males the alae venation (Fig. 14 ) is unique within the phylliids as the media anterior (MA) and media posterior (MP) veins fuse with the cubitus (Cu) at different locations along the cubitus and run fused to the wing margin (versus other phylliid genera which for example can have the MA and MP often fuse and run together to the wing margin, fuse with the Cu after first fusing together, never fuse and simply fade before reaching the margin, or fuse with the Cu at different locations but are also joined by the first radial (R1) and radial sector (Rs) and all run together to the wing margin). These autapomorphic features help to define the new genus Trolicaphyllium gen. nov. within the Phylliidae as well as differentiate them from the Chitoniscus sensu stricto.

Generic characteristics.

The Trolicaphyllium gen. nov. are small to medium, with females ranging from 42.0 mm (in the smallest recorded Trolicaphyllium erosus comb. nov.; Redtenbacher 1906) to 60.0 mm long (in the largest Trolicaphyllium sarrameaense , comb. nov.; Größer 2008b), with males from 38.5 mm to 43.3 mm (in the smallest and largest Trolicaphyllium brachysoma , comb. nov.; Größer 2008b). Typical general coloration is green, but in captivity orange/yellow has been induced (Fig. 19 ).

Legs. Both sexes have interior tibial lobes on the protibiae which span the full length, lack lobes on the protibial exterior, and the meso-, metatibiae are simple, lacking both interior and exterior lobes. In both sexes the profemoral interior lobe is broader than the exterior lobe (distinctly so in males with a width almost two times that of the exterior lobe, sometimes in females the interior and exterior are almost even in width). In both sexes the profemoral interior lobe is generally only marked with three or four broadly spaced teeth (quite dulled in females; slightly more serrate in males). Both sexes have the interior meso-, and metafemoral lobes slightly broader or about even in width to the exterior lobes, but the interior lobes are always more prominently marked by serration.

Antennae. Females have antennae with nine segments with segments I, III, VIII, and IX notably broader than the other segments (Fig. 4A ) and the stridulatory file has more than 35 teeth (Fig. 5A ). Males have antennae which range from 23 to 26 segments with most segments covered in setae which are longer than the segment is wide.

Head capsule. Males have well-developed ocelli (Fig. 13A ), and both sexes have head capsules which are marked throughout by distinct granulation which is relatively evenly spaced and, in some cases, appears to be in slightly anterior to posterior rows (Figs 7A , 13A ).

Thorax. The thorax is similar in both sexes with mesopleurae that are narrowly diverging from the anterior to the posterior and are marked with five to seven tubercles, occasionally with sparse setae interspersed (Figs 7A , 13A ). In both sexes the prescutum is about two times wider on the anterior than long with lateral margins marked by six to eight tubercles, and a prescutum surface which is only slightly granular. When viewed laterally, both sexes have the prescutum anterior rim marked prominently with a raised sagittal spine and both have a prosternum which is prominently marked by a broad, warty tubercle (Figs 8A , 13B ).

Wings. Female tegmina are always long, reaching onto abdominal segments VII or VIII and male tegmina are moderate in length, reaching onto abdominal segment III. Females always have highly reduced alae, no more than just a nub (Fig. 22A ). Male alae are always fully developed in an oval-fan configuration and reach onto abdominal segment IX (Fig. 14 ). Female tegmina have a subcoastal vein; radial vein which runs parallel with the media and splits into the first radial about halfway through its length and terminates in a radial sector and in a small radial to medial crossvein which does fully connect; a bifurcate medial vein; a bifurcate cubitus vein; and a first anal vein which fuses with the cubitus early on (Fig. 10A ). Male tegmina have a subcoastal vein; radial vein which runs parallel with the media throughout the full length of the wing and branches into the first and second radial about one third and two thirds of the way through the wing length respectively and terminates as the radial sector; the media runs parallel with the radius and has two media posterior splits near the central area of the wing and terminates as the media anterior; the cubitus is unbranched; and there is a first anal which fuses with the cubitus early on (Fig. 14 ). Male alae (Fig. 14 ) have a costal vein running along the anterior margin; a subcostal vein which runs for about two thirds of the length and then fuses with the costal vein; the radial vein is bifurcate when it splits about two fifths of the way through the wing length where they diverge, run parallel, then converge sharply at the apex but don’t seem to reach the wing margin; the media is the most unique feature of the alae as it splits early on into the media anterior and posterior which run parallel until the media posterior fuses with the cubitus followed by the media anterior also fusing with the cubitus; the cubitus is fused with the first anterior anal for the majority of the length until the first anterior anal splits and runs to the wing margin; the cubitus, media anterior, and media posterior run fused to the wing margin; the anal veins are split into two groups, the anterior anals and the posterior anals (with seven anterior anals and five posterior anals).

Abdomen. Both sexes have variable abdominal shapes; females can range from spade-shaped to broad and boxy with prominently projecting abdominal lobes VII and VIII; males can be narrowly-ovoid and lack lobes to broadening until segment VII and converging with lobes. Female subgenital plate is short and stout with the apex reaching the anterior margin of the terminal abdominal segment and ending in a fine point; the gonapophyses VIII are long and slender, slightly exceeding the apex of the terminal abdominal segment; the cerci are relatively flat, marked sparsely with a granular surface with margins slightly marked with setae (Fig. 11A ). Males have a broad, triangular vomer which is singularly pronged, hooking up into the paraproct.

Egg. Egg morphology is only known at present from Trolicaphyllium sarrameaense , comb. nov. (Fig. 15A-C ). Yasumatsu (1942) suggested an egg for Trolicaphyllium brachysoma comb. nov. but the specimen the eggs were from was not collected on New Caledonia and likely represents a different genus and is unrelated to Trolicaphyllium gen. nov. based upon the illustration given. This general egg description is based upon examined material and on images of eggs from several sources all appearing to come from Trolicaphyllium sarrameaense comb. nov. females. Average length approximately 3 mm long. Eggs when viewed laterally are somewhat rectangular but with the dorsal surface slightly convex and longer than the ventral, giving the egg a slight bent appearance (Fig. 15B ). Surfaces are marked throughout with shallow, irregular smooth patches which are accentuated by having darker coloration than the overall egg coloration. Eggs lack pinnae, but instead have small granulation scattered across the capsule which is most prominent and abundant along the capsule margins and notably sparse on the flat surfaces. The egg operculum is conically raised on the ventral margin only, not centrally raised like most phylliid eggs. The raised operculum is only about half as tall as wide and increases from the dorsal margin to the highest point on the ventral margin. The operculum apex has a similar granulation to that found on the capsule margins. Overall egg coloration variable, from a pale tan to light brown, or darker brown, with the pitting on the capsule darker in color and the granulation throughout lighter in color (Fig. 20 ).

Nymphs. Freshly hatched nymphs are known at present for Trolicaphyllium sarrameaense comb. nov. (Fig. 18A ) but are unknown for the other Trolicaphyllium gen. nov. species. Therefore, a comparison between species is not possible at this time. This generalized description is based upon images of Trolicaphyllium sarrameaense comb. nov. shared by Detlef Größer (Germany). Body long and slender; profemora and protibiae with thin interior lobes but lack exterior lobes; meso- and metafemora with thin interior and exterior lobes; meso- and metatibiae simple, lacking lobes. The base coloration throughout the antennae, head, thorax, abdomen, meso- and metafemora is black. Profemora and all tibiae and tarsi are lighter colored, ranging from dark brown to tan/reddish. All joints between the tibiae and femora are marked with white. The meso- and metafemoral exterior lobes are marked with a medial white spot occupying approximately the central third of the lobe. The abdomen is slender and longer than the antennae, head, and thorax combined. Centrally the abdomen is black, but the margins of segments II-IV and VI-VIII are bordered with a lime green color.

New combinations

Trolicaphyllium brachysoma (Sharp, 1898), comb. nov.

Trolicaphyllium erosus (Redtenbachher, 1906), comb. nov.

Trolicaphyllium sarrameaense ( Größer er, 2008a), comb. nov.

Etymology. Trolicaphyllium meaning "leaf that walks noiselessly". This generic epithet is a compound of the Latinized name Phyllium the type genus for the family (from Greek φυλλον, - ου (phyllon, - oy) + -um; Poitout 2007), coupled with the prefix tro lica from the Drehu (Dehu) language phrase which means "walk noiselessly" (Tyron 1967). We wished to honor the original inhabitants of this area by using a local traditional language. We chose this name because these beautiful insects are so elusive and noiselessly living in the trees where they are often overlooked. This new genus is neuter in gender, following Phyllium .

Distribution. At present Trolicaphyllium gen. nov. specimens are only known from the country of New Caledonia, with records from Grande Terre, Lifou, Tiga, Maré, Ile de Bélep, and L’Île-des-Pins islands (Fig. 21 ). Likely other islands may also be suitable, but we have yet to locate specimen records from museums or observations.

Figures

Figure 3. Adult female Trolicaphyllium cf. sarrameaense comb. nov. found feeding on Syzygium cumini Sarramea county, near La Foa, January 2021 (recorded and photographed by Sylvie Cazeres (IAC )) A dorsoanterior, habitus B dorsal, habitus.

Figure 4. Scanning electron micrographs of female antennae A, C Trolicaphyllium sarrameaense comb. nov. B, D Chitoniscus sensu stricto A, B overview of the antenna, medial view A right antenna B left antenna C, D third antennomere. Abbreviations: a 1 - a 9, antennomeres 1 - 9 st stridulatory file, sr stridulatory ridge. Scale bars: 300 µm (A, B), 200 µm (C, D).

Figure 5. Scanning electron micrographs of female stridulatory organs A, C Trolicaphyllium sarrameaense comb. nov. B, D Chitoniscus sensu stricto A, B overview of stridulatory ridge C, D teeth of stridulatory file. Scale bars: 100 µm (A, B), 20 µm (C, D).

Figure 6. Scanning electron micrographs of female scapus (1 st antennomere) A, C Trolicaphyllium sarrameaense comb. nov. B, D Chitoniscus sensu stricto A, B overview of scapus, lateral view C, D medial view. Scale bars: 200 µm.

Figure 7. Details of the head through thorax, dorsal A Trolicaphyllium sarrameaense comb. nov. (holotype) (DEI Hemimetabola, 100215) B Chitoniscus sp. " Suva " (RC Coll 18 - 176).

Figure 8. Lateral details of the head and thorax A Trolicaphyllium sarrameaense comb. nov. (holotype) (DEI Hemimetabola, 100215) B Chitoniscus sp. " Suva " (RC Coll 18 - 176).

Figure 9. Ventro-posterior view of live females showing their exposed coxae coloration A Trolicaphyllium sarrameaense comb. nov. taken by Thierry Salesne (New Caledonia) March 2011, in Vallee Pierrat, La Foa, Grand Terre B Chitoniscus sp. " Suva " (RC Coll 18 - 176) live photograph taken by Thierry Heitzmann (Philippines).

Figure 10. Female tegmina venation A Trolicaphyllium sarrameaense comb. nov. (Coll SLT) B Chitoniscus feejeeanus from SDEI ( 100213). Abbreviations: Sc (subcosta); R (radius); R 1 (radius 1); Rs (radial sector); R-M (radius to media crossvein); M (media); MA (media anterior); MP (media posterior); Cu (cubitus); CuA (cubitus anterior); CuP (cubitus posterior); 1 A (first anal).

Figure 11. Female genitalia details, ventral view A Trolicaphyllium sarrameaense comb. nov. (Coll SLT) B Chitoniscus sp. " Suva " (RC Coll 18 - 176).

Figure 12. Scanning electron micrographs of tarsi A, C Chitoniscus sensu stricto B Trolicaphyllium sarrameaense comb. nov. A male, overview B, C females, tarsomeres 1 - 5. Abbreviations: ar, arolium, cl, claw, eu 1 - 5, euplantula 1 - 5. Ta 1 - 5, tarsomere 1 - 5, ri, median ridgelike expansion. Scale bars: 500 µm.

Figure 13. Details of male head through thorax A, B Trolicaphyllium sarrameaense comb. nov., paratype male ( 100214); photographs by Arne Koehler (SDEI) C, D Chitoniscus sensu stricto A, C, D head through thorax, dorsal B head through thorax, lateral C Chitoniscus sp. from the NHMUK, photograph by RC D live Chitoniscus sp. " Suva ", photograph by Thierry Heitzemann (Philippines).

Figure 14. Male tegmina and alae venation Trolicaphyllium cf. brachysoma comb. nov. (Coll RC 16 - 094). Abbreviations: C (costa); Sc (subcosta); R (radius); R 1 (radius 1); R 2 (radius 2); Rs (radial sector); M (media); MA (media anterior); MP (media posterior); MP 1 (first media posterior); MP 2 (second media posterior); Cu + MA + MP (fused cubitus, media anterior, and media posterior); Cu (cubitus); Cu + 1 AA (cubitus and first anterior anal); 1 A (first anal); 1 AA- 7 AA (first-seventh anterior anal); 1 PA- 5 PA (first-fifth posterior anal).

Figure 15. Comparison of Chitoniscus sensu stricto and Trolicaphyllium gen. nov. eggs A-C Trolicaphyllium sarrameaense comb. nov., imaged by TB of eggs from Coll DG A dorsal B lateral C opercular (anterior) D-F Chitoniscus sp. " Suva " (RC Coll 18 - 272) D dorsal E lateral F opercular (anterior).

Figure 16. Scanning electron micrographs of specialized chorionic structures of the eggs A-C Trolicaphyllium sarrameaense comb. nov. D-F Chitoniscus sensu stricto A, D overview of micropylar plate B, E detail of micropylar plate C, F micropylar cap. Scale bars: 300 µm (A, D), 100 µm (B, E, F), 50 µm (C).

Figure 17. Scanning electron micrographs of chorionic microstructures on the eggs A-D Trolicaphyllium sarrameaense comb. nov. E-H Chitoniscus sensu stricto A, B mushroom-like granula C, D, G, H surface microsculpture C surface of the granula D exochorionic surface microstructures E, F pinnae. Scale bars: 100 µm (A, E), 20 µm (B, F), 10 µm (G), 5 µm (D), 3 µm (H), 1 µm (C).

Figure 18. Illustrations of freshly hatched nymphs for comparison, dorsal habitus. Illustrations by Liz Sisk (USA). Nymph size is approximated to be relative to each other based upon the few photographs available but is only an estimate A Trolicaphyllium sarrameaense comb. nov.; overall nymph length from head to tip of abdomen approximately 7 mm (Groesser 2008 b); illustration based upon photographs from Detlef Groesser (Germany) B Chitoniscus sp. " Suva' ' based upon images supplied by Mayk de Haan (Belgium).

Figure 19. Captive bred Trolicaphyllium sarrameaense comb. nov. dorsal, habitus, female reared and photographed by Detlef Groesser (Germany).

Figure 20. Trolicaphyllium sarrameaense comb. nov. eggs showing the variation in coloration, photographs by Sylvie Cazeres (IAC), eggs laid by females from Vallee Pierrat, Commune de La Foa A lighter colored eggs B first five eggs laid by the female from Figure 3.

Figure 21. Distribution map noting all presently known Trolicaphyllium gen. nov. records which could be traced and accurately noted. See Suppl. material 1 for full details for all records presented. Stars indicate a record based upon a specimen, circles represent a record based upon a photographic observation. Produced with SimpleMappr (Shorthouse, 2010).

Figure 22. Syntype females of Trolicaphyllium brachysoma comb. nov. the herein designated type species for the new genus. Photographs by Paul Brock (United Kingdom) of the set within the CUMZ A dorsal habitus with tegmina spread; note the lack of developed alae B dorsal habitus with tegmina closed.