Desmoxytes aurata Srisonchai, Enghoff & Panha

Srisonchai, Ruttapon, Enghoff, Henrik, Likhitrakarn, Natdanai & Panha, Somsak, 2018, A revision of dragon millipedes I: genus Desmoxytes Chamberlin, 1923, with the description of eight new species (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 761, pp. 1-177: 1

publication ID

http://dx.doi.org/10.3897/zookeys.761.24214

publication LSID

lsid:zoobank.org:pub:91658359-00AE-4319-ACBC-E9C544599C5B

persistent identifier

http://treatment.plazi.org/id/E0C412B2-9218-4B68-B925-774000C4F149

taxon LSID

lsid:zoobank.org:act:E0C412B2-9218-4B68-B925-774000C4F149

treatment provided by

ZooKeys by Pensoft

scientific name

Desmoxytes aurata Srisonchai, Enghoff & Panha
status

sp. n.

Desmoxytes aurata Srisonchai, Enghoff & Panha  sp. n. Figs 9, 10, 11, 12, 13, 14

Holotype.

Male (CUMZ), THAILAND, Surat Thani Province, Kanchanadit District, Khao Phanom Wang Cave, 9°05'27"N, 99°36'28"E, ca. 52 m a.s.l., 7 August 2015, leg. C. Sutcharit, R. Srisonchai, and ASRU members.

Paratypes.

10 males, 7 females (CUMZ), same data as holotype. 17 males, 3 females (CUMZ), 1 male, 1 female (ZMUC), 1 male (ZMUM), 1 male (NHMW), 1 male (NHMUK), THAILAND, Surat Thani Province, Kanchanadit District, Wat Praphutthabart Sri Surat, 9°11'11"N, 99°34'47"E, ca. 19 m a.s.l., 6 December 2016, leg. S. Panha and ASRU members.

Further specimens, not paratypes, all from THAILAND, Surat Thani Province: 8 males, 18 females, 3 broken females, 1 broken male missing right gonopod (CUMZ), Donsak District, Nang Gam Beach, limestone mountain, 9°18'53"N, 99°45'40"E, ca. 20 m a.s.l., 10 October 2008, leg. S. Panha, P. Tongkerd, and ASRU members. 7 males, 1 male missing left gonopod, 6 females, 1 male missing gonopods, 1 broken male missing left gonopod (CUMZ), Ko Samui District, Mo Ko Ang Thong National Marine Park, Ko Mae Koh, 9°39'06"N, 99°40'02"E, ca. 23 m a.s.l., 6 June 2009, leg. S. Panha and ASRU members. 1 broken male missing left gonopod, 4 males, 3 females, 1 male missing right gonopod, 1 male missing gonopods (CUMZ), Ko Samui District, Mo Ko Ang Thong National Marine Park, Ko Wua Talap, 9°38'08"N, 99°40'16"E, ca. 20 m a.s.l., 6 June 2009, leg. S. Panha and ASRU members. 1 male, 3 females (CUMZ), Donsak District, Nang Gam Beach, 9°18'53"N, 99°45'41"E, ca. 26 m a.s.l., 2 December 2015, leg. S. Panha, P. Tongkerd, and ASRU members.

Nakhon Si Thammarat Province: 1 male (CUMZ), Khanom District, Khao Krot Bureau of Monks, near Khao Krot Cave, 9°14'29"N, 99°48'07"E, ca. 19 m a.s.l., 23 October 2016, leg. W. Siriwut and ASRU members.

Diagnosis.

Body bright orange, low degree of elevation of paraterga, femora 5 and 6 strongly humped ventrally in middle part, collum with row of 3+3 anterior setae and metaterga with rows of 2+2 anterior and 2+2 posterior small tubercles. Similar in these respects to D. delfae  and D. perakensis  sp. n., but differs from those by having paraterga of collum quite long; lateral sulcus (ls) quite shallow; lamina lateralis (ll) stout and compact, ventral ridge (vrl) short; process (plm) of lamina medialis crenate; sternal lobe between male coxae 4 thin when seen in lateral view.

Etymology.

The name is Latin adjective and refers to the lamina lateralis (ll) of the gonopod which bears some resemblance to the “hooded” head of the oranda breed of goldfish ( Carassius auratus  ).

Description.

SIZE: Length 21-24 mm (male), 25-27 mm (female); width of midbody metazona ca. 1.7 mm (male), 2.1 mm (female). Width of head < collum < body ring 2 < 3 = 4 < 5-16, thereafter body gradually tapering towards telson.

COLOUR (Fig. 9 A–D): In life with body bright orange; antenna dark brown, except distal part of antennomere 7 and antennomere 8 whitish; head brown; paraterga, metaterga and surface below paraterga orange; legs, sterna and epiproct orange-ish yellow; a few basal podomeres whitish orange; prozona and metazona (metaterga) with wide black stripe, conspicuous on rings 4-19.

ANTENNAE (Fig. 10D): Moderately long and slender, reaching to body ring 6 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 10A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, almost horizontal, directed caudolaterad, with two inconspicuous setiferous notches on lateral margin.

TEGUMENT: Strongly shining and smooth; prozona finely shagreened; collum, metaterga, sterna and epiproct smooth; surface below paraterga finely microgranulate.

METATERGA (Fig. 10 A–C): With 2 transverse rows of setae and inconspicuous tubercles; metaterga 2-18 with 2+2 anterior and 2+2 posterior tubercles; metatergum 19 with 2+2 anterior and 2+2 posterior setae.

PARATERGA (Fig. 10E, F): Directed caudolaterad on body rings 2-17, elevated at ca. 30°-35° (male) 30° (female), directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, without tiny denticle near tip.

TELSON (Fig. 11 C–G): Epiproct: tip emarginate; lateral setiferous tubercles small and inconspicuous; apical tubercles inconspicuous. Hypoproct subsemicircular; caudal margin round, with very small and inconspicuous setiferous tubercles.

STERNA (Fig. 12): Cross-impressions shallow. Sternal lobe between male coxae 4 subrectangular (in some specimens subtrapeziform), tip subtruncate (in some specimens subemarginate or round).

LEGS (Fig. 11 H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 13, 14): Coxa (cx) longer than prefemur. Cannula (ca) slightly stout. Telopodite quite stout. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) somewhat stout. Mesal sulcus (ms) conspicuous and very deep; lateral sulcus (ls) shallow. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, stout and compact, anterolaterally with a distinct furrow; ventral ridge (vrl) short: lamina medialis (lm) well-developed; process (plm) short, wide and thin, tip crenate; distal lobe (dlm) distally with one lamella, tip directed anteriad; broad lobe (blm) indistinctly separated from distal lobe (dlm) by a shallow indentation. Solenomere (sl) long.

Distribution and habitat.

Known only from Surat Thani and Nakhon Si Thammarat Provinces. All specimens were collected in limestone mountains (on the mainland and on two islands) (Fig. 9E). We also surveyed other islands in Mo Ko Ang Thong National Marine Park, but found no specimens of D. aurata  sp. n. The new species is probably distributed along the islands in the Gulf of Thailand and also on the mainland near the type locality. We regard it as endemic for Thailand.

Desmoxytes aurata  sp. n. is morphologically similar to D. delfae  and D. perakensis  sp. n. in the remarkable orange colouration, as well as some morphological characters (except characters in diagnosis). These three species show allopatric distribution ranges, and the big mountain ranges known as the Nakhon Si Thammarat and Sunkala Khiri mountains possibly act as dispersal barriers.

Remarks.

The bright orange colouration is without doubt aposematic. There is some distinct variation within populations in the sternal lobe between male coxae 4, especially its shape: in most specimens the lobe is subrectangular, in others subtrapeziform, and its tip also varies - subtruncate/ subemarginate/ round. The shape of the sternal lobe of the new species is similar to that seen in D. delfae  and D. perakensis  sp. n., however, it looks thinner than those when seen in lateral view.

Coexisting species.

Desmoxytes cervina  was found together with the new species in some localities.