A revision of dragon millipedes II: the new genus Nagaxytes gen. nov., with the description of three new species (Diplopoda, Polydesmida, Paradoxosomatidae)
Author
Ruttapon Srisonchai
Author
Henrik Enghoff
Author
Natdanai Likhitrakarn
Author
Somsak Panha
text
European Journal of Taxonomy
2018
2018-09-25
462
1
44
journal article
28899
10.5852/ejt.2018.462
328c4344-2529-4aae-9c38-a3f9cb576c35
1467972
urn:lsid:zoobank.org:pub:60992A95-1F59-4407-9774-B8FC1545A8B4
Nagaxytes acantherpestes
(
Golovatch & Enghoff, 1994
)
gen. et comb. nov.
Figs 2
,
6–10
Desmoxytes acantherpestes
Golovatch & Enghoff, 1994
: 51
–53, figs 21–28.
Desmoxytes acantherpestes
–
Enghoff 2005
: 96. —
Decker 2010
: 28. —
Nguyen & Sierwald 2013
: 1240.
Diagnosis
Metaterga 4–19 with one row of 2+2 posterior spines (anterior row absent). Similar in this respect to
N. gracilis
gen. et sp. nov.
but differs from this species by having paraterga shorter; degree of elevation of paraterga lower; sternal lobe between male coxae 4 subtrapeziform; lamina lateralis swollen, stout, short.
Material examined
Holotype
THAILAND
:
♂
,
western coast of Siam Gulf (Gulf of Thailand), Hua Hin [Prachuap Khiri Khan Province
,
Hua Hin District
],
8 Aug. 1979
,
B. Petersen
leg. (
ZMUC 000101457
).
Fig. 6.
Nagaxytes acantherpestes
(Golovatch & Enghoff, 1994)
gen. et comb. nov.
A
. Drawing of ♂, holotype
(
ZMUC 000101457).
B
. Parasitic mite.
C
. Habitat.
Other material
THAILAND
:
2 ♂♂
,
1 ♂
(gonopods lost),
1 ♀
,
Prachuap Khiri Khan Province
,
Kui Buri District
,
Hat Kham Subdistrict
,
Ban Yan Sue
,
12°03′12″ N
,
99°37′52″ E
, ca.
147 m
a.s.l.,
31 Aug. 2007
,
ASRU members leg
. (
CUMZ
).
Redescription
SIZE. Length
32–34 mm
(male),
36 mm
(female); width of midbody metazona ca.
2.2 mm
(male), 3.0 mm (female). Width of head <body ring 2 = 3 <collum <4 <5–16, thereafter body gradually tapering towards telson.
COLOUR. Specimens in life brown. Colour in alcohol: after 29 years changed to pale brown; head, antennae, collum, metaterga, surface below paraterga, sterna, epiproct pale brown; paraterga brownish white.
COLLUM (
Fig. 7A
). With setae in anterior row and intermediate row, spines in posterior row; paraterga of collum elevated at ca. 35–40°, directed caudolaterad, with two conspicuous notches at lateral margin.
ANTENNAE (
Fig. 7D
). Moderately long and slender, reaching to body ring 5 or 6 (male) and 5 (female) when stretched dorsally.
TEGUMENT. Quite dull. Stricture between prozona and metazona shallow, wide.
METATERGA (
Fig. 7A–C
). With one or two transverse rows of setae and spines; metatergum 2 with?1+?1 anterior setae (inconspicuous) and 2+2 posterior spines; metaterga 3–19 with 2+2 posterior spines (lateral spines very long).
PLEUROSTERNAL CARINAE. On body ring 2 long, crest-like; on body ring 3 a small ridges; thereafter missing.
PARATERGA (
Figs 7F–G
,
8B
). Directed caudolaterad on body rings 2–18, elevated at ca. 60° (male) 50°– 60° (female), directed increasingly caudad on body ring 19.
TELSON (
Fig. 8C–G
). Epiproct quite short; tip usually subtruncate (in some specimens slightly emarginate); lateral setiferous tubercles conspicuous, long, digitiform; apical tubercles conspicuous. Hypoproct subtriangular; caudal margin subtriangular, with inconspicuous setiferous tubercles.
STERNA (
Fig. 8H–J
). Cross-impressions quite deep. Sternal lobe between male coxae 4 swollen, subtrapeziform when seen in caudal view; base broad; tip slightly or deeply emarginate.
GONOPODS (
Figs 9
,
10
). Coxa subequal in length to femur. Cannula long and slender. Telopodite quite long and slender. Prefemoral part ca. ¾ as long as femur. Femur quite long and slender. Mesal sulcus conspicuous, deep, wide; lateral sulcus conspicuous, very deep. Postfemoral part conspicuous, quite short. Solenophore well-developed: lamina lateralis swollen, stout, short, compact: lamina medialis very long; with a swollen base, gradually becoming thinner towards tip; apically fringed with several small spines; tip directed mesoventrad. Solenomere quite long, curved, tip directed ventrad.
Distribution and habitat
This species is known from two locations (Hua Hin and Ban Yan Sue) in Prachuap Khirikhan Province. We believe that the
holotype
was probably collected from limestone habitats because the
type
locality (near Hua Hin) lies in a limestone area. Specimens collected by us were from limestone habitats. It has been found crawling on rocks or on leaf litter.
Fig. 7.
Nagaxytes acantherpestes
(Golovatch & Enghoff, 1994)
gen. et comb. nov.
, ♂, holotype (ZMUC 000101457).
A
. Anterior body part.
B
. Body rings 8–10.
C
. Posteriormost body rings and telson.
D
. Head and antenna.
E
. ♂ leg 5 (right).
F–G
. Midbody ring.
Fig. 8.
Nagaxytes acantherpestes
(Golovatch & Enghoff, 1994)
gen. et comb. nov.
, ♂, holotype (ZMUC 000101457).
A
. Body rings 8–10.
B
. Paraterga of ring 10.
C–D
. Last ring and telson.
E
. Hypoproct.
F–G
. Epiproct.
H–J
. Sternal lobe between coxae 4.
Fig. 9.
Nagaxytes acantherpestes
(Golovatch & Enghoff, 1994)
gen. et comb. nov.
, specimen from Ban Yan Sue (Thailand), right gonopod.
A
. Mesal view.
B
. Dorsal view.
C
. Lateral view.
D
. Ventral view.
Fig. 10.
Nagaxytes acantherpestes
(Golovatch & Enghoff, 1994)
gen. et comb. nov.
, specimen from Ban Yan Sue (Thailand), right gonopod.
A
. Lateral view.
B
. Mesal view.
C
. Ventral view.
D
,
F
. Subdorsal view.
E
. Dorsal view.
This species is likely to be syntopic with
Desmoxytes planata
(Pocock, 1895)
at Ban Yan Sue; however, we noticed that the habitats of these two species are clearly different.
Nagaxytes acantherpestes
gen. et comb. nov.
lives on the ground or on limestone rocks while
D. planata
was found on tree trunks near garbage.
Decker (2010)
identified one male in NHMG, collected from Thanboke Khorani National Park,
Krabi Province
(
8°23′12″ N
,
98°44′16″ E
) as
D. acantherpestes
. This specimen might perhaps be ‘
D.’ gigas
Golovatch & Enghoff, 1994
(in the ‘
gigas
’ group) because the location falls in the distribution range for this group in South
Thailand
whereas
Nagaxytes
gen. nov.
(the ‘
acantherpestes
’ group) is limited to western
Thailand
. Moreover, Thanboke Khorani National Park and Hua Hin are far apart, about
500 km
.
This species is distributed in a narrow area; we regard
N. acantherpestes
gen. et comb. nov.
as endemic to
Prachuap Khiri Khan Province
,
Thailand
.
Remarks
In the original description,
Golovatch & Enghoff (1994)
did not comment on the live colouration of this species. We did not photograph living specimens, but our collector noticed a brown colouration.
Golovatch & Enghoff (1994)
also described
D. acantherpestes
as lacking pleurosternal
carinae
, but after we re-examined the
holotype
and examined all newly collected specimens, we found the pleurosternal
carinae
as crest-like on ring 2, as small ridges on ring 3, thereafter absent. There is a variation in the tip of the epiproct which in some specimens is subtruncate, in others slightly emarginate.
On some specimens we found parasitic mites, probably of the genus
Leptus
Latreille, 1795 (
Fig. 6B
). The mites infested the millipede on the metaterga. This association reminds us of what
Srisonchai
et al.
(2018)
found in
Desmoxytes cervina
(Pocock, 1895)
: several engorged
Leptus
mites attached to the millipede body.