Otostigmus spinosus Porat, 1876

Siriwut, Warut, Edgecombe, Gregory D, Sutcharit, Chirasak & Panha, Somsak, 2014, Brooding behaviour of the centipede Otostigmus spinosus Porat, 1876 (Chilopoda: Scolopendromorpha: Scolopendridae) and its morphological variability in Thailand, Raffles Bulletin of Zoology 62, pp. 339-351 : 345-348

publication ID

https://doi.org/ 10.5281/zenodo.5458839

publication LSID

lsid:zoobank.org:pub:D576585B-1DCD-40A8-831F-1408698EA7D9

persistent identifier

https://treatment.plazi.org/id/03A487BD-FFC9-FFFE-FEC1-CA29E192FAD8

treatment provided by

Tatiana

scientific name

Otostigmus spinosus Porat, 1876
status

 

Otostigmus spinosus Porat, 1876 View in CoL

( Figs. 5 View Fig , 6 View Fig )

Otostigmus spinosus Porat, 1876: 22 View in CoL Branchiotrema nitidulum Tömösváry, 1885: 26 View in CoL , table 3, figs. 19, 20 Otostigmus spinosum: Haase, 1887: 71 , Taf. 4, fig. 70a–d Otostigmus spinosum ab. hirtipes Haase, 1887: 71, Taf. 4, fig. 71a–c Otostigma spinosum: Pocock, 1891b: 414 ; Pocock, 1894: 312 Otostigmus spinosus: Kraepelin, 1903: 116 View in CoL , fig. 53; Kraepelin,

1904: 247; Attems, 1930a: 152, fig. 182; Attems, 1930b: 118;

Verhoeff, 1937: 212; Chamberlin, 1939: 3; Chamberlin, 1944:

1; Lewis, 1991: 340, figs. 11–14; Khanna, 1994: 467; Lewis,

2001: 37, figs. 75–78; Khanna, 2001: 206; Schileyko, 2007:

81, fig. 5; Lewis, 2010: 6, figs. 8–13 nec Otostigmus (O.) spinosus: Lewis, 1982: 365 , figs. 25–31; Lewis,

1984: 37, fig. 3.15

Type locality. Indonesia: Java .

Distribution. Java, Sumatra, New Guinea, Burma, Laos, Thailand, Vietnam, Malaysia, India?

Material examined. Malaysia: BMNH 1898.9.15.75–76 general collection, 2 of 3 specimens in tube labeled “ Otostigmus sp. ” from Penang . Laos: CMUZ 00232 , one specimen from Ban Kra- Som, Attopue , Laos (15°0'27.2" N 106°51'14.6" E) GoogleMaps . Thailand: CUMZ 00224 View Materials , one specimen from Wat Tham Wararam, Phanom district , Surat Thani (8°53'2.7" N 98°40'1.4" E) GoogleMaps . CUMZ 00228 View Materials , two specimens from Khao Sok, Phanom district , Surat Thani (8°53'37.3" N 98°33'107" E) . CUMZ 00225 View Materials , five specimens from Wat Kerewong, Thap Put district, Phang-nga (8°31'54.8" N 98°34'37.8" E) GoogleMaps . CUMZ 00226 View Materials , one specimen from Sairung waterfall, Takua Pa district, Phang-nga (8°44'28.3" N 98°16' 43.1" E) GoogleMaps . CUMZ 00231 View Materials , 53 specimens from Surin islands, Phang-nga (9°26'41" N 97°53'30.3" E) GoogleMaps . CUMZ 00230 View Materials , one specimen from Sichon district , Nakhon Si Thammarat (9°5'31.4" N 99°54'23.2" E) GoogleMaps . CUMZ 00229 View Materials , three specimens from Tham Wang Thong, Khuan Khanun district , Phatthalung (7°40'53.5" N. 100°0'56.6" E.) GoogleMaps . CUMZ 00223 View Materials , one specimen from Tham Sumano, Srinagarindha district , Phatthalung (7°35'11.9" N 99° 52'3.2" E) GoogleMaps , CUMZ 00227 View Materials , one specimen from Huaito waterfall, Khao Phanom district , Krabi (8°13'35.5" N 98°53'2.5" E) GoogleMaps .

Diagnosis. 17–22(24) antennal articles, basal 2.3–2.8 articles glabrous dorsally. Forcipular coxosternum with 4–6 main teeth. Forcipular trochanteroprefemoral process with one apical and two inner teeth. Tergite surface smooth, without keels, but with scattered small spines or setae; paramedian sutures starting from TT4–7 and complete margination from TT7–15. Tergite of ultimate leg-bearing segment with or without depression. Sternites with incomplete paramedian sutures occupying 10–30% of anterior part of sternite, posterior part with shallow depression. Posterior margin of sternite of ultimate leg-bearing segment concave, lateral margins converging. Coxopleural process with one to three apical spines, one sub-apical or none, one lateral or none, and one dorsal spine. Ultimate legs long and slender, spine formula on prefemur VL-4 or 5, VM-2–4, M-2–5 and DM- 1–4 (including corner spine). Locomotory legs with two accessory spurs; legs 1–3 to 1–5 in equal frequency (rarely 2, 6 or 7) with two tarsal spurs, legs 5–21 (rarely 3, 7 and 8) with one tarsal spur. One tibial spur on legs 1–3 (rarely leg 4). Femoral spur only on leg 1. Dorsal side of leg 20 with one spine at end of prefemur.

Description. Maximum body length approximately 38 mm. Body colour of living animal greenish black except tergite of ultimate leg-bearing segment, which is reddish black. Trochanteroprefemur yellowish white or light brown. Legs light blue or purple except prefemur, which is light yellow. Cephalic plate without sulci or sutures. Preserved specimens dark purple.

Antennae with 17–22 articles ( Fig. 5C View Fig ), 24 articles in one specimen. Basal 2.5–2.8 articles glabrous dorsally ( Fig. 6B View Fig ); atypically 2.3. Basal 2.5–2.8 articles glabrous ventrally ( Fig. 6A View Fig ). Antennae reach segments 4–6 (5 or 6 in large specimens). Forcipular trochanteroprefemoral process bearing one apical and two inner teeth (rarely 3; see Figs. 6D–E View Fig ). Coxosternal tooth plate wider than long with 4, 5 or 6 main teeth in equal frequency (rarely 3 or 7; see Fig. 6C–F View Fig ), separated into two groups; inner three or four teeth usually fused and outer 1 or 2 acute ( Figs. 5B View Fig , 6C, 6F View Fig ), basal part with one transparent, fine seta on each side, atypically with 1 transparent spine and 2 small spines in a depression ( Fig. 6F View Fig ). One specimen shows an abnormal condition with both tooth plates fused together ( Fig. 6D View Fig ). Coxosternum lacking median suture in some specimens ( Fig. 6D View Fig ), median diastema reaching to base of tooth plate, connecting with basal oblique sutures ( Fig. 6C, 6E, 6F View Fig ). Angle of basal oblique sutures ca 105–110°. Telopodite 2 of second maxilla with one strong transparent spine on each side.

First tergite overlapping cephalic plate, without transverse sulcus ( Fig. 5A View Fig ). Tergites with paramedian sutures complete from TT5 to 6 (rarely TT7); margination typically starting on TT11 to 15 (atypically TT9–10). Tergite surface ( Figs. 5D View Fig , 6G View Fig ) with oblique suture anteriorly on TT3 to 5 and with paramedian sulci on TT3 or 4 to 18 (to TT 19 to 20 in large specimens). Tergite of ultimate leg-bearing segment ( Fig. 6L View Fig ) usually with median furrow on posterior part (rarely absent). Sternites ( Fig. 5E View Fig ) with short paramedian sutures on anterior part, occupying 10–30% length of sternite. Surface of some sternites with small scattered setae and depressions grouped in triangular arrangement (one atypical specimen with depression continued behind end of paramedian suture), all mostly found on posterior part of sternite ( Fig. 6H View Fig ). Sternite of ultimate leg-bearing segment ( Fig. 6K View Fig ) with sides converging posteriorly, posterior margin concave (one specimen with depression on surface). Oval spiracles present on segments 3, 5, 8, 10, 12, 14, 16, 18 and 20 ( Fig. 5F–H View Fig ). Coxopleural process moderately long with two apical spines (rarely 1 or 3), one subapical spine or none, one to two lateral spines or none, and one dorsal spine or none ( Fig. 5I View Fig ). Coxopleura with dense pore field covering whole area except on ventro-distal part of coxopleural process ( Figs. 5J View Fig , 6M View Fig ), pore-free area on coxopleural process extending 50–70% length from distal part to the margin of sternite of ultimate leg-bearing segment ( Fig. 5I View Fig ). Ultimate legs long and slender with ratios of lengths of prefemur and femur 6:4, tibia and tarsus 2 1.5:1; tarsus 1 and tarsus 2 03:2. Prefemoral spines in four rows ( Fig. 5K–L View Fig ), formula VL-4–5 (rarely 2, 6 and 7), VM-3–4 (rarely 1 or 2), M-2–5 (usually 4), DM-1–4 including corner spine (rarely 5 or 6).

Locomotory legs with or without short setae, usually legs 1–5 with two tarsal spurs (rarely 1–2 or up to 6 and 7), the subsequent legs to 21 with one tarsal spur. One tibial spur on legs 1–2 or 3 in equal frequency (rarely 1–4). Leg 1 with femoral spur (rarely absent). Two accessory spurs and pretarsal claw present on all legs. Dorsal part of prefemur of leg 20 with one spine ( Fig. 5M, N View Fig ) at the margin of prefemur (atypically found only on one side). Anterior face of leg 20 in some males with a short, rounded, variably depigmented projection on distal end of tarsus 1 ( Fig. 6I View Fig ); similarly proportioned projection on tarsus 1 of leg 21 in two of four specimens with a projection on leg 20; projections most strongly developed in the largest specimen ( Fig. 6J View Fig ).

Remarks. The taxonomic status of O. spinosus and O. punctiventer Tömösváry, 1885 is still unclear, the two species possessing the synapomorphic character of a distal prefemoral spine on leg 20. In this study, we found that the range of variation of some taxonomic characters in O. spinosus to overlap with the description of O. punctiventer sensu Lewis, 2010 (see Table 2). Moreover, the geographic distributions of O. punctiventer and O. spinosus overlap at least on peninsular Malaysia. For these reasons, the identification based on morphology of O. spinosus and O.punctiventer is complicated and needs to be reassessed. The nominate subspecies of O. spinosus is recognised in this work; O. spinosus spinosus Porat, 1876 and O. spinosus nannus Chamberlin, 1939 are currently valid subspecies, though the latter has been questioned as possibly being based upon a juvenile specimen of Ethmostigmus rubripes spinosus ( Newport, 1845) ( Schileyko & Stagl, 2004). The type locality of O. spinosus nannus is Doormanpad, Irian Jaya/West Papua (New Guinea). We found one specimen of Otostigmus in the NHM from Mimika River, Irian Jaya, that we identified as O. spinosus but its associated label indicated affinities to O. punctiventer .

In Thailand, O. spinosus is widespread throughout the southern part of the country ( Fig. 1 View Fig ). In all localities this species was found together with other Otostigmus species such as O. multidens , O. rugulosus , O. astenus , and O. scaber . As some taxonomic characters, such as the range of appearances of tibial and tarsal spurs on the locomotory legs, number of antennal articles, and numbers of apical and lateral spines on the coxopleural process are variable ( Table 1), there can be problems in determining species. On some occasions we found animals in which the spine on the prefemur of leg 20, a diagnostic character, was absent on one side. The characteristic of leg 20 (and variably 21) bearing a distal projection on the anterior face of tarsus 1 is apparently unique to this species and, with the data at hand, appears to be a secondary sexual characteristic. The three specimens possessing this feature that exhibit the genital segments are all males and its elaboration with growth is consistent with it being sex-specific. Other Otostigminae have distal processes on different articles of the ultimate leg-pair in males, e.g., on the inner side of the femur in Digitipes Attems, 1930 , and on the inner side of the tibia in Otostostigmus (Parotostigmus) tibialis Brölemann, 1902 . The inconsistency of taxonomic characters may be problematic when it involves the purported diagnostic characters of species and may lead to misidentifications. Molecular data could assist with revaluating species delimitation in the Otostigmus rugulosus group (sensu Lewis, 2010).

Variation and development of taxonomic characters. In this study, we found two broods that belong to adolescent stages that permitted investigating the development of some taxonomic characters. In hatchlings in brood D, an early first adolescent stage, most taxonomic characters are incompletely developed. Contrastingly, in the four surviving hatchlings of brood A, some taxonomic characters (including some species-diagnostic characters) are fully developed. Our observations reveal that some traditional taxonomic characters such as number of antennal articles, number of glabrous articles, and number of apical spines on the ultimate leg coxopleuron vary during the life span. A distinguishing character of this species (the prefemoral spine on leg 20) is strongly fixed, being conserved between the mother and second adolescent stage hatchlings except in one specimen (see Table 2) presumably due to abnormal development. Colouration differs between young and the mother; hatchlings show a very light yellowish or brown and magenta colour whereas mothers are dark greenish brown.

Kingdom

Animalia

Phylum

Arthropoda

Class

Chilopoda

Order

Scolopendromorpha

Family

Scolopendridae

Genus

Otostigmus

Loc

Otostigmus spinosus Porat, 1876

Siriwut, Warut, Edgecombe, Gregory D, Sutcharit, Chirasak & Panha, Somsak 2014
2014
Loc

Otostigmus spinosus

Kraepelin K 1903: 116
Pocock RI 1894: 312
Pocock RI 1891: 414
Haase, E 1887: 71
Haase, E 1887: 71
Tomosvary E 1885: 26
von Porat C 1876: 22
1876
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