Dimorphodes mancus morotaiense, Hennemann & Tirant, 2023

Dimorphodes mancus morotaiense n. ssp.

( Fig. 6-9, 15 G-H)

ZooBank: http://zoobank.org/ 59562DFC-F654-4B4F-B3FA-B657B4B3FE54

Holotype, ♀, Indonesia, Morotai Island, North Maluku Regency, Daruba , VII.2021 [ IMQC].

Paratypes

- 2 ♀, 4 ♀ (nymphs), Indonesia, Morotai Island, North Maluku Regency, Daruba , VII.2021 [ IMQC] .

- 43 ♀, Indonesia, Morotai Island, North Maluku Regency, Daruba , VII.2021 [ IMQC] .

- 1 ♂, 18 ♀, 1 ♀ (penultimate instar), Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [coll. FH, No’s 1243–62 to 81]

- 1 ♂, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , XI.-XII.2012 [coll. FH, No’s 1243–1] .

- 1 ♂, 12 eggs, ex Zucht M. Ortiz ( Frankreich) 2019, Herkunft, Indonesien, Morotai Island , Dae Majiko village, F1-Generation [coll. FH, No’s 1243–2 & E1] .

- 28 ♂, 31 ♀, 25 eggs, ex Zucht F. Hennemann 2020-22, Herkunft, Indonesien, Morotai, Daeo Majiko village , leg. A. Yasin, F2/F3- Generation [coll. FH, No’s 1243–3 to 61, E2] .

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [ IRSN] .

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [ RMNH] .

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [ SMFM] .

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [ MNHU] .

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [coll. OC] .

- 10 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , VII.2012 [coll. RTC] .

- 1 ♂, 1 ♀, Indonesia, Morotai Island , Daruba, VIII.2020 [coll. EB] .

Etymology. – The name refers to the distribution of this new subspecies, which is an endemic of Morotai Island.

Differential diagnosis. – Only the eggs of this new subspecies allow easy separation from D. mancus mancus from Halmahera and the western adjacent northern Maluku Islands. They differ at first glance by the much darker blackish brown overall colour ( Fig. 16 G-H), whereas the eggs of D. mancus mancus are ochre or pale buff with chestnut brown to mid brown mottling ( Fig. 16 I-J). The basic shape of the capsule is similar but in this new subspecies there is a distinct central indention at the dorsal and ventral surfaces and the sub-polar indentions are notably more pronounced so that the polar area is protruding more when viewed laterally. The micropylar plate is considerably larger in relation to the capsule (length> 0.3 the length of capsule vs. <0.29 in mancus mancus ), broader and shield-shaped in outline whereas it is rather pear-shaped with the anterior portion narrowed in mancus mancus . The outer margin of the micropylar plate is also somewhat bulgier in the eggs of this new subspecies. Moreover, the operculum is relatively higher and more conical in shape with the capitular stalk larger and the lateral capitular protrusions blackish in colour and not orangey brown as in mancus mancus .

Description.

No detailed descriptions of the adult insects are provided herein, since there are no consistent morphological differences from the nominate form of D. mancus . Hence, the original description by Bates (1865: 345) is for now regarded as sufficient to characterize also D. mancus morotaiense n. ssp. The following characterizations mainly aim to summarize the range of intraspecific variability seen in the specimens at hand for examination.

♀ ( Fig. 6-8). Medium to fairly large for the genus (body length 100.0-115.0 mm) and of rather typical shape. Antennae with 20 antennomeres. Degree of armature of body and legs somewhat variable, with the wild specimens having all of the armature somewhat more pronounced than the captive reared specimens ( Fig. 7 G-H) and being smaller on average. Notable variability is seen in the colouration, some of which is illustrated in figure 8. The colour basically ranges from light cream over various tones of ochre, buff, grey and brown to almost black, often with greenish portions and occasionally olive or green specimens are encountered ( Fig. 6E, 8E). Usually, the insects are to a variable degree and covered throughout with dark mottling or show various light cream to white markings. Some of these colour combinations give the insects a somewhat lichenose appearance. Often there is a pale cream or white sub-apical transverse band on the femora. Vertical posterior portion of head black.

♂ ( Fig. 9). Medium sized (body length 58.0- 70.3 mm) and stocky for the genus with small, scale-like tegmina and tiny vestigial alae, that are spiniform to conical in shape ( Fig. 9H). The tegmina exactly reach to the tip of the alae, so that the posterior margin of the tegmina touches the anterior upright A. ♀ terminalia in dorsal aspect [ FH]. B . ♀ terminalia in lateral aspect [ FH]. C . ♀ terminalia in dorsal aspect [ FH]. D . ♂ terminalia in lateral aspect [ FH]. E . ♂ terminalia in dorsal aspect [ FH]. F . ♂ head and prothorax in dorsal view [ FH]. G . ♂ head and prothorax in ventral view [ FH]. H . ♀ head and prothorax in dorsal view [ FH]. J . ♀ head and prothorax in ventral view [ FH]. K . ♀ head and prothorax in lateral view [ FH]. L . ♂ head and prothorax in lateral view [ FH] .

portion of the alae. Antennae with 20 antennomeres. Occurring in a common brown or rarer green form. The brown forms range from light ochre to drab mid brown and may occasionally have a slight olive wash or a faint dark green to olive medio-longitudinal stripe along the dorsal body surface. Ventral surface of the body in brown specimens often dark orangey or reddish. Tegmina and alae black, the tegmina with the outer margin slightly orange. Lower ventral portions of genae black.

Eggs ( Fig. 16 G-H): Of moderate size for the genus, capsule of a distinctive shape with several indentions that produce convex and concave portions. Capsule oval in cross-section, 1.36x longer than wide and just scarcely longer than high. Dorsal and ventral surfaces indented and distinctly concave in lateral aspect, the polar-area bulgy and obtusely triangular in lateral aspect with a shallow indention dorsally and ventrally. Capsule surface wholly granulose and somewhat uneven with several variously shaped lowered regions. Micropylar plate somewhat more than one-third the length and more than half the width of capsule, slightly longer than wide, shield-shaped and somewhat narrowed anteriorly. Posterior end with a median indention and the outer margin bulgy; surface weakly concave and granulose. Micropylar cup a rounded swelling and with a small cup-like structure below that is placed on the posteromedian gap of the plate. Median line short and indistinct exteriorly. Operculum ovalular and strongly conical in centre to produce a strong and high capitular stalk, surface plain and granulose; height including capitulum about one-third the length of capsule. Capitulum formed by about eight lamellate vertical and irregularly shaped ridges. General colour of capsule and micropylar dark brown, the lowered portions of capsule and operculum black. The protrusions of the capitulum blackish with the extreme outer portions slightly ochraceous.

Measurements [mm]:

- Length (including capitulum) 4.9-5.0,

- Length 3.8-3.9,

- Width 2.9-3.0

- Height 3.5-3.7,

- Length of micropylar plate 1.6-1.7.

Comments. – The nominate subspecies D. mancus ( Bates, 1865) was originally described based on five specimens from the Wallace collection now in OUMNH and originated from the islands of Bacan and Ternate. The species has subsequently also been recorded from the islands of Gebe and Obi (Redtenbacher, 1908: 366). The accuracy of the record from Sulawesi by the same author has been doubted by Hennemann (2021: 94) because the species is unlikely to be present on Sulawesi and the concerned specimen(s) in the collection of NHMW are not traced. Specimens from Obi, Ternate and Halmahera are also contained in the first author's collection.The Obi population however shows notable morphological differences from specimens originating from all other islands but these differences deserve further evaluation.

Günther (1934: 87) recorded D. mancus from Pilowo, Guguti (“Goegoeti”) Morotai and stated the unique ♂ he had examined to fully fit the original description provided by Bates (1865: 345). Indeed, both ♀ and ♂ of this new population show no significant and frequent morphological differences from specimens examined from the islands of Halmahera, Gebe, Ternate and Bacan. In general D. mancus shows a significant range of intraspecific variability on all islands. Thus, Morotai was merely believed to be part of the geographic range of D. mancus . It was only once eggs were received, which immediately showed that the Morotai population was not identical. These eggs are very different from eggs of the Halmahera population ( Fig. 16 I-J) and led to our classifying of the Morotai population as a subspecies of D.mancus . This decision might deserve further evaluation by genetic analyses which might also help to reveal the extent of the variability between the populations. The lack of morphological differences between the adults however suggests close relationship. Several hundred eggs of the Halmahera and Morotai populations were available from captive breeding and were carefully examined to delimit intraspecific variability. The variability is low within both populations, rendering the morphological differences between the eggs of these two populations consistent. With egg morphology the only concrete feature to allow differentiation between the populations,the Morotaipopulation is here considered an offshoot of the Halmahera population and that of the western adjacent islands. Whether there are also differences between the Halmahera population and those of the western islands Bacan, Gebe and Ternate should be

A. PT dorsal view (captive reared) [FH, No. 1243-6]. B. PT dorsolateral view (captive reared) [FH, No. 1243-26]. C. PT dorsolateral view [FH, No. 1243-65]. D. PT dorsolateral view [FH, No. 1243-69]. E. PT dorsolateral view [FH, No. 1243-62].

subject to a more comprehensive survey of the island forms of D. mancus or a revision of the genus Dimorphodes as a whole.

This classification of the Morotai population of D. mancus is also supported by the significant number of other insect species, which follow this trend. In numerous cases the Morotai populations are subspecies with sibling subspecies from the other northern Maluku Islands. An example is Wallace's golden birdwing butterfly Ornithoptera croesus Wallace, 1859 , which has five subspecies distributed throughout the northern Maluku Islands to which it is endemic. Also, a phasmid species, the recently described leaf insect Phyllium tobeloense bhaskarai Cumming et al., 2019 also endemic to Morotai, is an offshoot of the Halmahera population and parallels this Dimorphodes mancus subspecies as the ♂ and ♀ are morphologically almost identical with only the eggs allowing easily differentiation. The consistent differences between the eggs of the two populations are illustrated in figures 16G-J.

Any broader discussion and descriptions of the different island populations may be subject to forthcoming genetic and morphological approaches that aim to delimit the species ranges within the genus Dimorphodes , which as stated above is in need of a significant revision.

Captive breeding of D. mancus morotaiense n. ssp. in Europe has been successful. Culture stock was imported in 2020 by M. Ortiz ( France) and eggs laid by the F1–generation were kindly forwarded to the first author. The adults are sturdy and capable of reproducing in large numbers with the hatching rates of eggs close to 100% and a mortality of nymphs almost non-existent in humid conditions and average temperatures of 20-25°C.Nymphs are robust throughout their entire development as are the adult insects, which in captivity have proven fairly long-lived with ♀ in particular reaching up to one year of age as adults. Eggs are dropped to the ground singularly by the ♀ and an average of 3- 4 eggs are laid per day per ♀. At the temperatures mentioned above eggs hatch after about 4-5 months and nymphs reach maturity in 5-6 months. In captivity D. mancus morotaiense n. ssp. is seen to be fairly polyphagous with at least bramble ( Rubus spp. , Rosaceae ), raspberry ( Rubus idaeus , Rosaceae ), wild and cultivated roses ( Rosa spp. , Rosaceae ), hawthorn ( Crataegus spp. , Rosaceae ), hazel ( Corylus avellana , Betulaceae ), beech ( Fagus sylvatica , Fagaceae ), oaks ( Quercus robur and Q. petraea , Fagaceae ) and salal ( Gaultheria shallon , Ericaceae ) frequently accepted as alternative food plants by all stages. Due to the polyphagous tendencies in captivity this subspecies is likely also quite polyphagous in its natural habitats on Morotai.While nymphs usually rest on their hostplants,adults, but ♀ in particular, are frequently seen to rest on the cage floor between leaf litter and on or under pieces of bark or other shelters. If grabbed the insects usually show cateleptic behaviours with the front legs closely stretched anteriorally inline with the body and the two remainder pairs of legs stretched out backwards.They willonly move and walk away if further disturbed. Males produce slight rustling noises by rubbing the hinder margin of their tegmina on the spiniform, upward directed anterior margin of the vestigial alae. As typical for members of the subfamily Phasmtidae sensu stricto (= Lanceocercata) the ♂ grasps the ♀ subgenital plate ( Fig.8F) during the copulation and not abdominal sternum VII as in other phasmatodeans. In Dimorphodes a hump-like and rough opercular organ is seen at the base of the subgenital plate of ♀ ( Fig. 7D, F), which is similar to the structures seen in members of the subfamily Megacraniinae (see Hennemann, 2020) or various taxa of the New Zealand clade Acanthoxylini . The function of the large sensory area of the profurcasternum is not known but is believed to have olfactory functions like e.g. in members of the Oriental Heteropterygidae (see Hennemann et al., 2016).