Review of the Southeast Asian millipede genus Antheromorpha Jeekel, 1968 (Diplopoda, Polydesmida, Paradoxosomatidae)

Abstract The genus Antheromorpha is redefined and shown to comprise 11 valid species: Antheromorpha miranda (Pocock, 1895), Antheromorpha bistriata (Pocock, 1895), Antheromorpha comotti (Pocock, 1895), Antheromorpha festiva (Brölemann, 1896), Antheromorpha harpaga (Attems, 1937), Antheromorpha mediovirgata (Carl, 1941), Antheromorpha minlana (Pocock, 1895), Antheromorpha pardalis (Pocock, 1895), Antheromorpha paviei (Brölemann, 1896), comb. n., Antheromorpha rosea Golovatch, 2013 and Antheromorpha uncinata (Attems, 1931). Three new synonymies are proposed: Antheromorpha bivittata (Pocock, 1895) and Antheromorpha melanopleuris (Pocock, 1895) are synonymized under Antheromorpha miranda (Pocock, 1895), and Antheromorpha orophila (Carl, 1941) under Antheromorpha comotti (Pocock, 1895). Detailed descriptions and illustrations of fresh material from Thailand and Malaysia are given, especially regarding colour patterns which appear to be crucial for accurate species identifications. Two Antheromorpha species proposed by Attems are redescribed, based on type material. The genus is rediagnosed and a key and a distribution map are also provided. At least in Thailand, adult Antheromorpha rosea have been found to occur every year only for one or two weeks in September or October, disappearing thereafter.


Introduction
The Southeast Asian millipede genus Antheromorpha Jeekel, 1968 is currently known to comprise 13 medium-sized to very large species showing moderately developed to very prominent paraterga and, above all, unlike the other, numerous genera of the basically Oriental tribe Orthomorphini Brölemann, 1916 to which it belongs, a very deeply bifid gonopod tip (Jeekel 1968, Golovatch 2013a). This genus is assumed to be particularly similar to the largely sympatric genus Orthomorpha Bollman, 1893, the species of which, like Antheromorpha, normally have large bodies and prominent paraterga, coupled with usually bright colour patterns. The main difference between these two genera lies in Orthomorpha spp. showing only a poorly differentiated gonopod tip, usually feebly bi-or trifid (Likhitrakarn et al. 2011). Antheromorpha species have hitherto been recorded in Myanmar (9), Thailand (2), China (1) and Vietnam (1).
The only subsequent addition to the list seems to be A. rosea Golovatch, 2013, the first species of the genus to be reported from southern China, yet not placed into any of the species groups (Golovatch 2013a(Golovatch , 2013b.
The present paper provides an updated review of Antheromorpha, based on abundant new samples from Thailand and Malaysia. In addition, type material of two species of Attems (1931Attems ( , 1937 has been revised and properly redescribed. As a result, the genus is rediagnosed and a key and a distribution map are also provided.

Material and methods
New material was taken throughout Thailand and from Malaysia between 2006 and 2015 by SP and members of the Animal Systematics Research Unit, Chulalongkorn University. Animals, both live and alcohol material, were photographed in the laboratory. Specimens were preserved in 75% ethanol and morphological investigations were carried out in the laboratory using an Olympus stereomicroscope. Scanning electron micrographs (SEM) of gonopods coated with gold were taken using a JEOL, JSM-5410 LV microscope, and the gonopods were returned to alcohol after examination. Digital images of the specimens were taken in the laboratory and assembled using the "Cell D " automontage software of the Olympus Soft Imaging Solution GmbH package. In addition, line drawings of gonopods were prepared. Type material of two Attemsian species of Antheromorpha from Thailand and Vietnam, housed in the Naturhistorisches Museum Wien, Austria (NHMW), was photographed with Dino-Eye USB Camera AM423Z, the digital images assembled using the automontage software technique and the gonopod structure redrawn. Most of the new material is kept in the Museum of Zoology, Chulalongkorn University (CUMZ), Bangkok, Thailand, except for some duplicates donated to the collections of the Natural History Museum of Denmark, University of Copenhagen, Denmark (ZMUC), the Zoological Museum, State University of Moscow, Russia (ZMUM) and the NHMW, as indicated in the text.
Collecting sites were located by GPS using the WGS84 datum.
In the synonymy sections, D stands for the original description or subsequent descriptive notes or appearance in a key, R for subsequent record or records, whereas M for a mere mention.
Remarks. Brachytropis Silvestri, 1896, was originally established to distinguish several species of Orthomorpha Bollman, 1893 which occurred in Myanmar and Indochina (Jeekel 1963), with Orthomorpha miranda Pocock, 1895, as type species (Silvestri 1896). Because that name had been preoccupied by Brachytropis Fieber, 1858 (Hemiptera) (Jeekel 1963), Jeekel (1968 proposed a substitute name, Antheromorpha, with the same type species. In his later review of the genus, Jeekel (1980) provided its diagnosis, refined its scope, redescribed some of the constituent species and discussed their taxonomic statuses.

Antheromorpha minlana (Pocock, 1895) Figs 3C, 21
Orthomorpha minlana Pocock, 1895: 816 (D).  Remark. This species was described and still remains known only from Minhla, Tharrawaddy District, Myanmar (Pocock 1895). An indefinite number of ♂ and ♀ syntypes of A. minlana must be deposited in the London Museum, UK (Pocock 1895). According to H. Enghoff (in litt.), the ZMUC collection contains a sample (1 ♂, 1 ♀, both mounted on insect pins) labelled "Orthomorpha minhlana Poc. // ex typ. //Minhla // Birma fea". Remarks. This species was described and still remains known only from a single ♀, the holotype which comes from Palon in Pegu, Myanmar (Pocock 1895) and is kept in the Genova Museum, Italy (Jeekel 1980). The species is similar to A. miranda (Pocock, 1895), but has a different colour pattern of the metaterga, the latter showing yellowish paramedian spots in front of the transverse sulcus (versus yellowish paramedian stripes), coupled with the sulcus starting with segment 2 (versus segment 5). Since the colour pattern is one of the most important taxonomic characters for species discrimination in the genus, A. pardalis for the time being is regarded as a separate species. However, only the discovery of topotypical ♂ specimens can provide decisive information concerning the identity of this species (Jeekel 1980). , this species is distinguished by a more Orthomorpha-like colour patterm (only paraterga being contrasting light), yet, like a rather typical Antheromorpha, its solenophore tip is deeply split. It is the latter character that justifies the assignment of this species to Antheromorpha. The ♂ holotype of A. paviei is deposited in the Paris Museum, France (Brölemann 1896(Brölemann , 1904.
Gonopods (Figs 10-12) with femorite about 3 times as long as prefemoral (= strongly setose) part. Femorite rather stout and long, strongly curved, postfemoral portion demarcated by an oblique lateral sulcus; tip of solenophore (sph) rather deeply bifid; process d slender, rounded to nearly pointed; process m rounded, longer than process v. Remarks. This species was described from Muok Lek, Thailand (Attems 1931). Enghoff (2005), based on ZMUC material, added another four localities: Kamphaeng Phet Province; Sitang, Northeast Thailand; Phu Kradung; Phu Kugio, field on way to communist camp, Chayaphum Province. We revised Attems' type specimens, both in NHMW, and herewith designate a lectotype to ensure that the name-bearing specimen is a complete ♂. In most of their characters, the new samples are very similar to the type series except for body size and the shape of paraterga. In one and the same population, variation in the shape of paraterga is often observed, these ranging from more to less convex laterally and more or less strongly drawn caudad behind the rear tergal margin (Figs 8A, C, F, 9A, Figure 11. Antheromorpha uncinata (Attems, 1931), ♂ from Wat Tham Phromlok Khaoyai. A, B right gonopod, mesal and lateral views, respectively C-F distal part of right gonopod, mesal, lateral, subcaudal and suboral views, respectively. Scale bar: 0.2 mm. C, F, J-L). In addition, colour variations can be seen, the body being mostly red (prevailing), orange or yellow, with all possible intergradations (Fig. 7). It is noteworthy that only adults show colour variations, whereas juveniles are colourless. At Pang Rimkorn, Chiang Rai Province, A. uncinata has been observed as showing swarming behaviour. Golovatch, 2013 Figs 13-15, 21 Antheromorpha rosea Golovatch, 2013a: 23 (D).   Coloration of live animals pinkish (Fig. 13A), with an anterior black band on metaterga and collum; head and antennae blackish, legs dark to light brown; coloration in alcohol, after six months of preservation, faded to light pinkish to pale yellowish (Fig. 13B-H), with a dark brown to blackish brown band on anterior metaterga and collum; head and antennae blackish to light brown, legs light brown to pale yellowish. Antennae long (Fig. 13A, C), extending behind metaterga 3 when stretched dorsally (♂, ♀). In width, head < segment 3 = 4 < collum < segment 2 < 5-17 (♂, ♀), gently and gradually tapering thereafter (Fig. 13B). Paraterga very strongly developed (Fig. 13B-H), mostly slightly upturned, all lying below dorsum, set at about upper 1/3 of midbody height, caudal corner almost to fully pointed, increasingly acutangular, from narrowly rounded to nearly pointed, especially strongly so in segment 15, thereafter slightly curved mesad (Fig. 13B, D, F). Pleurosternal carinae complete crests with a sharp caudal tooth in segment 2, likewise a sharp caudal tooth in segments 3 and 4, a small, mostly sharp tooth until segment 16 (♂, ♀) (Fig. 13C, E). Sterna delicately and sparsely setose, without modifications, but with a pair of small, rounded, fully separated cones between ♂ coxae 4 (Fig. 13I, J).

Antheromorpha rosea
Remarks. The available descriptions (Golovatch 2013a(Golovatch , 2013b of this species were sufficiently detailed to necessitate only a few notes on variation and some new illustrations (Figs 13-15) to show coloration, certain structural details and the gonopod conformation based on new material. This species was described from the ♂ holotype (kept in Senckenberg Museum Frankfurt, Germany) from Gaoligong Shan Moutains, south of Pianma, 25°58'N, 98°40'E, 1600-1700 m a.s.l., Yunnan Province, China (Golovatch 2013a), a little later reported (1 ♂, 1 ♀, deposited in the National Natural History Museum, Sofia, Bulgaria) nearly from the same place (Golovatch 2013b). Even though both these Yunnan localities (Fig. 21) lie far away (ca 730 air-km) from the new Thai records, even despite minor variations, the species identity is beyond doubt.
At least in Thailand, adult A. rosea have been found to occur every year only for one or two weeks in September or October, disappearing thereafter. , width of midbody pro-and metazonae 1.8-2.5 and 2.9-3.7 mm (♂), 2.7-3.1 and 3.6-4.4 mm (♀), respectively (vs length 28-30 mm, as given in the available descriptions (Brölemann 1896;Attems 1937).
Coloration of live animals dark red to red-brownish, with contrasting light red to pale pinkish paraterga and epiproct; a complete inverted V-shaped line on collum, a pair of parallel oblique bands on metazonae and a pair of parallel bands on prozonae  (Brölemann, 1896), ♂ from Sungai Bekok (A), ♂ from Kampung S. Ramasamy (B-J). A habitus, live coloration B, C anterior part of body, dorsal and lateral views, respectively D, E segments 10 and 11, dorsal and lateral views, respectively F-H posterior part of body, lateral, dorsal and ventral views, respectively I, J sternal cones between coxae 4, subcaudal and sublateral views, respectively. of following segments; legs and venter brownish to pale brown; coloration of alcohol material after one year of preservation faded to castaneous or pale brown; paraterga, epiproct and parallel bands faded to pale pinkish or pale yellow, legs and venter paler brown to yellowish (Fig. 16B-J).
Gonopods (Figs 17,18) with femorite relatively short and rather stout, evidently curved and enlarged distad, postfemoral portion demarcated by an oblique lateral sulcus; tip of solenophore (sph) very deeply bifid, with a long, slender, nearly pointed process d; process m with an acute terminal lobule, longer than a small and terminally rounded process v.
Remarks. The new specimens fully agree with the most detailed and beautifully illustrated redescription of the species as given by Brölemann (1904), whereas the original description (Brölemann 1896) was indeed so concise and contained no type locality other than "Indo-Chine" that Attems (1937), obviously being unaware of Brölemann's 1904 paper, reiterated only the very short diagnosis of Orthomorpha festiva Figure 17. Antheromorpha festiva (Brölemann, 1896), ♂ from Kampung S. Ramasamy. A, B right gonopod, lateral and mesal views, respectively. Scale bar: 0.4 mm. contained in Brölemann (1896). According to Brölemann (1904), however, this species (1 ♂ and 1 ♀ syntypes, now in the Paris Museum) actually derived from "Siam". Enghoff et al. (2004), likewise unaware of Brölemann's (1904) detailed redescription, erroneously listed A. festiva as coming from "southern Vietnam", but very soon after that the mistake was corrected for "Siam" (Enghoff 2005).
The above samples thus derive from the first specified localities in Thailand. Moreover, A. festiva appears to be not only new to the fauna of Malaysia, but it also seems to be quite widespread across the southern half of Malay Peninsula both within lowland southern Thailand and Western Malaysia, being confined there to elevations not exceeding 60 m a.s.l. (Fig. 21).  (Brölemann, 1896), ♂ from Kampung S. Ramasamy. A, B right gonopod, mesal and lateral views, respectively C-F distal part of right gonopod, submesal, sublateral, subcaudal and suboral views, respectively. Scale bar: 0.2 mm.
Remarks. This is the only species in this genus that has been reported from Vietnam (Attems 1937). It differs from congeners in the gonopod solenophore being deeply bifid and showing a long and slender process d and a bidentate tip (Fig. 20C).
Key to the known species of Antheromorpha, chiefly based on ♂. Sternal lamina between ♂ coxae 4 with a paramedian pair of evident, high, nearly pointed, fully separated, setose cones (Fig. 16I, J). Gonopod process d very long (Figs 17A, B, 18A, B). Southern Thailand and Western Malaysia (Fig. 21) Fig. 2A). Northern Myanmar (Fig. 21) ..........A. bistriata The much better explored Thailand harbours three apparently strictly allopatric species. Even in Chiang Mai Province, where A. uncinata and A. rosea co-occur, allopatry looks complete, without any mixed populations observed. The pair A. uncinata and A. festiva shows a remarkable geographical gap in southern Thailand, more specifically, in the northern half of the Malay Peninsula (Fig. 21). This gap strongly reminds of that observed between Orthomorpha lauta Golovatch, 1998and O. insularis Pocock, 1895(Likhitrakarn et al. 2011. There can be no doubt that further collecting efforts, especially in still very poorly explored regions such as Laos, China, Malaysia and Vietnam, will reveal more Antheromorpha species, as well as further records of the known congeners. Cambodia remains an especially poorly prospected country in Indochina whence no Antheromorpha has been documented yet (Likhitrakarn et al. 2015).