Otostigmus rugulosus Porat, 1876

Lewis, John G. E., 2010, A revision of the rugulosus group of Otostigmus subgenus Otostigmus Porat, 1876 (Chilopoda: Scolopendromorpha: Scolopendridae), Zootaxa 2579, pp. 1-29 : 3-6

Otostigmus rugulosus Porat, 1876

( Figs 1–7 )

Otostigmus rugulosus Porat, 1876: 21 . Mauritius

Otostigma carinatum var insulare: Pocock, 1889: 288 (nec Haase 1887). Mergui Archipelago, Burma Otostigma carinatum: Pocock, 1891: 412 . (nec O. carinatus Porat 1876 ). Burma, Andamans. Otostigma rugulosum: Pocock, 1891: 413 . Burma, Andamans.

Otostigma owenii Pocock, 1892: 319 . Owen’s Island, Mergui Archipelago, Burma. Syn. nov. (see below) Otostigmus rugulosus: Brölemann, 1895: 527 . Seychelles.

Otostigmus rugulosus: Kraepelin, 1903: 115 , fig 52. Siam [ Thailand].

Otostigmus oweni: Kraepelin, 1903: 116 .

Otostigmus rugulosus: Kraepelin, 1904: 246 . Siam [ Thailand], Bangkok. Otostigmus rugulosus: Gravely, 1910: 162 . Burma, (identified by Kraepelin). Otostigmus rugulosus: Gravely, 1912: 71 . India, Assam.

Otostigmus ( O.) rugulosus: Attems, 1930a: 144 .

Otostigmus ( O.) oweni: Attems, 1930a: 152 . Burma.

Otostigmus ( O.) ruglosus striaturatus Verhoeff, 1937: 216 . Malacca [Peninsular Malaysia]. Otostigmus rugulosus: Verhoeff, 1939: 94 . Mauritius.

Otostigmus ( O.) scaber: Lewis 1992: 440 , figs, 14–18. (nec Porat 1876). Nepal. Otostigmus oweni: Khanna, 1994: 464 . India, Arunachal Pradesh and Meghalaya. Otostigmus rugulosus: Khanna, 1994: 466 . India, Meghalaya and Himachal Pradesh; Andaman and Nicobar Islands. Otostigmus rugulosus: Khanna, 2001: 206 . India, Tamilnadu, Madras (as type locality!). Otostigmus ( O.) rugulosus: Lewis, 2001: 25 , figs 48–52. Sumatra, Nias Island. Otostigmus ( O.) rugulosus: Lewis, 2002a: 84 , figs 2–10. Mauritius; Rodriques. Otostigmus ( O.) rugulosus: Lewis, 2007: 10 , figs 1–4. Seychelles.

Diagnosis (based on the material described here and data from Mauritius and Rodrigues (Lewis, 2002a)).

Antennomeres 21 (19, 20), the basal 2 to 2.25 (2.4) glabrous. Each forcipular coxosternal tooth plate with four main teeth, typically the inner two on each side partially fused and rounded, the outer two acute, the outermost smaller than the other three. Sometimes a small outer fifth subsidiary tooth. Tergites with or without low rounded lateral keels on posterior segments. Spinules sometimes present on posterior tergites in some populations. Paramedian sutures occupying anterior 30% to 55% of mid and posterior sternites, usually with a shallow depression at end of each paramedian suture, a posterior median depression and sometimes lateral posterior depressions. Sternite 21 with sides converging posteriorly. Coxopleuron typically with two apical and one subapical or three apical spines, one lateral and one dorsal spine. A second lateral spine in some populations or two apical and three lateral spines. Ultimate leg prefemora with three (rarely four) rows of spines. Legs 1 to 11 or up to18 with two tarsal spurs. Leg 20 and ultimate legs without tarsal spurs (leg 20 rarely with one).

Type material examined. SMNH. Two syntypes, specimen 1, 34 mm, specimen 2, 32 mm. Labelled Otostigmus rugulosus v. Por. Mauritius 1855, Colleg Klinberg. Riksmuseet, Entomologiska Afdelning.

Description. (Data for specimen 2 in parentheses). Antennomeres 0[d] + 9[d] (17[d] + 21), the basal 2.25 (2) glabrous. 4+4 worn forcipular coxosternal teeth, the two inner on each side partially fused, the outermost much smaller than the others, with an indication of an additional outer subsidiary tooth on the right (fig. 1). Process of forcipular trochanteroprefemur with two low inner teeth.

Tergite paramedian sutures complete 4 (5) with low median ridge or keel from 3 (5). Low lateral keels formed on each side of paramedian sulci on 7 to 17 (10 to 14) (fig. 2). With lateral corrugations from 5 to 18. Spinules absent. Marginate from 9 (7).

Paramedian sutures occupying anterior 33% to 50% on anterior sternites, 55% on posterior sternites, the sutures terminating in very shallow depressions. Trace of posterior median and posterolateral depressions on some sternites (fig. 3). Sternite 21 narrowed posteriorly, length to width 1:1.1 (1:1.36) (figs. 4, 5). Sternite 21 in specimen 1 is longer than is usually the case.

Coxopleuron with two apical spines, one subapical and one dorsal near the apex. The tube contains two ultimate legs, the prefemora of each with four rows of spines: one with VL 4, VM 2, M 2, DM 1, CS 1 (fig. 6), the other with VL 4, VM 2+1, M 1, DM 1, CS 1. NB Typically there are three rows not four.

The specimens have all legs missing except the first pair. Porat (1876) gave: legs 1 to 16 with two tarsal spurs, 17 to 19 with one, 20 without. Kraepelin (1903) gave 1 to 14 (18) with two tarsal spurs.

Other material. BMNH. Six specimens, 35 to 43 mm, labelled Otostigma rugulosum Porath. Rangoon. E.W. Oates 89.7.15.34. (Pocock’s 1891 material).

Description. Antennomeres (20) 21. Complete tergite paramedian sutures begin 5 to 11, marginate from (7) 8 (9). One specimen with low median keel only, five with five weak keels, without spinules. Sternites with weak depressions at end of paramedian sutures and one or three weak posterior depressions. First 14, 15 or 18 pairs of legs with two tarsal spurs, the subsequent to 19 with one. Leg 20: seven legs without a tarsal spur, one with, ultimate without. Coxopleural process with two apical, one subapical, one lateral and one dorsal spine. Ultimate leg VL4, VM (2)3, M 0(2), DM 2, Cs 1.

BMNH. Four specimens 22–53 mm, with old pencilled label Gt. Cocos Is, Oates 89.7.15.26 and a recent label Otostigmus scaber Porat. (Pocock’s 1891 O. carinatum ).

Description. Antennomeres (19) 20. Two specimens have an additional outer subsidiary (fifth) tooth on each tooth plate. Complete tergite paramedian sutures from 4, 5 or 8, marginate from 5, 6, or 7. Three of the four have tergites with small scattered spinules on the posterior tergites. Two lack lateral keels, a third has five sharp keels from 15 to 19. The lateral corrugations form two additional irregular keels on each side from 14 to 18. The smallest specimen lacks tergite spinules but has a median keel from 3, nine keels from 7 and seven from 12 to 19, these being narrow but rounded. This may be a juvenile character. Some sternites with weak depressions at end of paramedian sutures and posterior median depression. First 11 or 12 pairs of legs with two tarsal spurs, the subsequent to 19 with one, 20 and ultimate without. Coxopleural process with three apical, one (two) lateral and one dorsal spine. Prefemoral spines typically VL 4, VM (2)3, M 0, DM 2, CS1.

BMNH. Five specimens 43 to 64 mm labelled Otostigma carinatum (Porath) 89.7.15.25 Reef Island (Tavoy) E. W. Oates (c & p) and two specimens, both 58 mm with labels Ot. carinatum, Por ? Reif Isl. Tavoy 89.7.15.25 and Otost. rugulosum Por. ( carinatus Por non Poc), probably by Kraepelin. Antenomeres (20) 21.

Description. Five specimens have the forcipular trochanteroprefemur with three lateral teeth rather than two. Complete tergite paramedian sutures begin (5) 6, marginate from 6, 7 or 8. Tergites with very low median keel but no lateral keels. A few small scattered spinules on posterior tergites in six of the seven specimens. Tergite 21 with deep posterior longitudinal depression. Coxopleuron with two lateral spines. Legs with two tarsal spurs to 15 16 or 17. Leg 20 with one or none. Most specimens lack ultimate legs.

BMNH. Four specimens 30–39 mm, labelled Otostigmus scaber Bangkok, 97.9.71.30–33.

Description. Antennomeres (20) 21. Complete tergite paramedian sutures begin (5) 6, marginate from 6, 7, 8 or 9. Tergites with low median keel and low lateral keels on posterior tergites in three specimens and with few small spinules on posterior tergites. Tergite 21 with deep posterior median depression. Some sternites with weak depressions at end of paramedian sutures and one or three posterior median depressions. Most with two apical and three lateral coxopleural spines. First twelve or fifteen pairs of legs with two tarsal spurs, the subsequent to 19 with one, 20 and ultimate without. Coxopleural process with two apical, one subapical. two lateral and one dorsal spine. Prefemoral spines VL3, VM2, M0, DM2, CS1.

Remarks. As noted above the forcipular coxosternal teeth of the syntypes are worn. Fig.7 shows the condition before any wear has taken place.

There has been some confusion as to the identity of Otostigmus rugulosu s (type locality Mauritius) and two other species described by Porat in 1876, namely O. scaber and O. carinatus , both from China. Further confusion was due to the proposal of Otostigma carinatum var. insulare by Haase (1887) for specimens from Java and Ceylon [ Sri Lanka] and subsequently recorded from the Mergui Archipelago, Burma by Pocock, (1889).

Pocock (1891) recorded both O. rugulosum and O. carinatum from many localities in Burma. He described O. carinatum as having tergites “either slightly wrinkled and sparsely spicular, or strongly carinate and subserially spicular” and O. rugulosum as presenting “very many points of strong resemblance with Ot. carinatus in which “ the tergites although strongly or weakly wrinkled do not appear to be spicular.” He “did not think that Dr Haase’s variety insulare is of any great value.”

Kraepelin (1903) considered O. carinatus to be a junior synonym of O. scaber but elevated Haase’s Otostigma carinatum var. insulare to specific status as O. insularis . Furthermore he correctly regarded Pocock’s records of O. carinatum from Burma as referable to O. rugulosus .

Gravely (1910) in a paper which listed the Scolopendridae of the Indian Museum identified by Kraepelin reported that Pocock’s (1889) Mergui specimens O. carinatus var. insulare showed no specific differences from the O. rugulosus identified by Kraepelin stating that “the finely grooved polished terga of all these specimens are in striking contrast to the strongly ridged granular terga of our specimen of O. insularis .”

Thus Kraepelin and Pocock differed in their concept of O. rugulosus and O. carinatum (= O. scaber ). For Pocock the critical character was the presence (in O. scaber ) or absence (in O. rugulosus ) of spinules. Kraepelin (1903) gave for O. scaber tergites, at least from segment 7 with seven to nine strongly defined sharp-ridged mostly finely serrated keels, the surfaces between them finely spine-streaked (“Kielstreifen”) and for O. rugulosus , the median keel very prominent from 7, flanked by two deep longitudinal sulci, laterally with reticulate wrinkles.

Attems (1930a) followed Kraepelin’s description of O. scaber , but for O. rugulosus gave tergites keeled from 5 or 6, spine-streaked (dornstrichelig) from 16 and sometimes with sparse spinules (Dornstrichelchen).

Lewis (2000) concluded that species (of Otostigmus ) should not be separated solely on the basis of the presence or absence of ‘spines’ on the tergites. If this premise is followed then Pocock’s specimens of O. carinatus from Burma are O. rugulosus as Kraepelin (1903) maintained. A specimen of O. rugulosus from Nepal was misidentified as O. scaber by Lewis (1992) and subsequently corrected by him ( Lewis, 2002a).

With the present state of our knowledge O. rugulosus is probably best regarded as showing considerable variation in the degree of development of the tergite ridges or keels and the extent of the spinules on the tergites. The Mauritius and Rodrigues populations would appear to lack tergite spinules, other populations may, or may not, have them.

Distribution. India; Nepal; Mauritius; Rodrigues; Seychelles; Andaman Islands; Burma; Thailand; Indonesia (Sumatra). Not recorded east of the Malaysian peninsula.

Figures

FIGURES 1 – 7. Otostigmus rugulosus. Fig. 1. Forcipular coxosternal toothplates and left trochanteroprefemoral process. Syntype specimen 1. Fig. 2. Tergite 12. Syntype specimen 1. Fig. 3. Sternite 12. Syntype specimen 1. Fig. 4. Terminal segments ventral. Syntype specimen 1 (coxopleural pores not shown). Fig. 5. Terminal segments ventral. Syntype specimen 2 (coxopleural pores not shown). Fig. 6. Ultimate leg prefemur ventral from a syntype. Fig. 7. Forcipular coxosternal toothplates and left trochanteroprefemoral process. Solitude, Rodrigues after Lewis (2002). Scale line = 0.5 mm.