Proterotaiwanella tanabei, Bonato & Foddai & Minelli, 2002

Bonato, Lucio, Foddai, Donatella & Minelli, Alessandro, 2002, A new mecistocephalid centipede from Ryukyu Islands and a revisitation of ‘ Taiwanella’ (Chilopoda: Geophilomorpha: Mecistocephalidae), Zootaxa 86, pp. 1-12 : 3-8

Proterotaiwanella tanabei n. sp.

Material examined. Holotype: female, total length 21 mm; from Gushikawa­son , Kume Island (Okinawa Prefecture, Japan), 23 February 1992, Tsutomu Tanabe legit.

Depository of holotype: National Science Museum, Tokyo, Japan

Etymology. The species is named after Tsutomu Tanabe, who collected the only specimen known.

Description of holotype.

Body slightly depressed, tapering in the posterior fourth.

Colour (of preserved specimen in alcohol): head and forcipular segment orange; the remaining body homogeneously yellow, without dark patches.

Antennae ( Fig. 1 ) 2.3 times longer than cephalic plate, distally only slightly attenuate. Antennal articles 1.0­1.2 times longer than wide, but for the terminal one which is 2.1 times longer than wide. Articles I to IV only slightly asymmetrical, with internal margin longer than external margin. Setae scattered, diverse in size, up to 0.1 mm long, on articles I to ca. VII. Setae more dense and uniform in size on remaining articles. Three longitudinal rows of spine­like sensilla (‘sensilla microtrichoidea’ of Ernst, 1983, 1997, 2000) at the basis of each article ( tab. 1 ). Groups of button­like sensilla on both ventral and dorsal sides of most articles ( tab. 1 ). A group of 2­3 tiny spines on the ventral side of article IX. Terminal article provided with ca. 40 club­like sensilla (‘sensilla basiconica’ of Ernst, 1979, 2000), ca. 12 m long, on both external and internal sides, and ca. 3 spear­like sensilla (‘sensilla brachyconica’ of Ernst, 1981, 2000), ca. 10 m long, at the apex.

Cephalic plate ( Fig. 1 ) flattened, sub­trapezoid, 1.6 times longer than wide, its maximum width at the level of the anterior fifth. Lateral margins nearly straight and convergent backwards, anterior margin convex with a short median incision, posterior margin straight. Scutes uniformly evident on the whole dorsal surface. Frontal line and posterior paramedian sulci absent. Setae symmetrically arranged.

Clypeus ( Fig. 2 ) 1.8 times wider than long. Paraclypeal sutures complete, strongly convergent backwards. Two sub­triangular clypeal plagulae, laterally not in contact with the paraclypeal sutures, their maximum length only 0.2 times the medial length of the clypeus; no micropores on the plagulae. Remaining clypeus homogeneously areolate, with 4 pairs of long and regularly arranged setae and ca. 30 button­like sensilla mainly grouped on two lateral areas. Mid­longitudinal areolate band sub­triangular.

Labrum ( Fig. 2 ). Mid­piece 2.3 times longer than wide, uniformly sclerotised, posteriorly pointed. Side­pieces sub­trapezoid, anterior margins straight, medially convergent backwards, internal margins parallel and well separated, posterior margins entire and convex in the medial part. A row of ca. 20 finger­like processes on the dorsal surface of each side­piece, along the posterior margin, extending on the medial two thirds of the margin width. Each side­piece divided into an anterior and a posterior ala by a sinuous sclerotised line, which is convex forwards on the medial part. Internal margin of the anterior ala reduced to a point. No hair­like projections on the posterior ala.

Buccae ( Fig. 2 ) without spicula. Areolation limited to a narrow band along anterior margin and paraclypeal suture. Setae absent. Stilus well developed, straight, pointed forwards.

Mandible ( Fig. 3 ) with ca. 5 well­developed and ca. 2 rudimentary pectinate lamellae. Lamellar teeth similar in shape, their size increasing slightly and gradually towards the apex of each lamella. First lamella with 6 teeth, intermediate (fourth) lamella with 11 teeth. Basal tooth large, pointed and bearing hair­like projections, mainly along the dorsal margin. Short hyaline scales emerging on the ventral surface of the mandible, at the basis of the lamellae.

First maxillae ( Fig. 4 ). Coxosternum ca. 2.6 times wider than long, mid­longitudinally divided, not areolate but for an anterior band, with 1+1 ventral setae. Lateral margins of coxosternum convergent forwards, aligned with the lateral margins of telopodites. Coxal projections and telopodites uniarticulated, each comprising a sclerotised proximal half with 3 and 7 setae respectively and a hyaline terminal half without setae. Hyaline scales absent.

Second maxillae ( Fig. 4 ). Coxosternum sub­rectangular, ca. 1.4 times wider than long, its total length 2.2 times the medial length; anterior and posterior margins concave, lateral margins parallel, postero­external corners only slightly projecting. Coxosternum undivided, without mid­longitudinal suture. Ventral surface of coxosternum homogeneously sclerotised, almost wholly areolate, with 6+2 setae on the antero­medial part and a few pores along the lateral margins. Metameric pores opening in lateral position, at about the mid­length of coxosternum; foraminal processes virtually absent. Telopodite of second maxillae relatively slender and short, not overreaching the telopodite of the first maxillae. Basal article of telopodite 2.7 times longer than wide, straight and uniformly wide, with a few strong setae on the internal side of the distal end and with some scattered short spines. Intermediate article of telopodite not swollen, with some distal setae. Terminal article of telopodite 1.3 times longer than the intermediate article, quite slender, with a few strong setae on the internal side of the distal part. Praetarsus in form of a rudimentary truncate claw bearing 2 tiny spines ( Fig. 5 ).

Forcipular segment ( Fig. 6 ). Coxosternum, pleurites and telopodites largely exposed beyond the lateral sides of the cephalic plate; tarsungulum overreaching the anterior margin of the cephalic plate. Forcipular tergum sub­trapezoid, 1.2 times wider than long, lateral margins concave. Anterior and posterior parts of forcipular tergum covered by cephalic capsule and tergum of first leg­bearing segment respectively; exposed part slightly narrower than posterior margin of head. Tergum homogeneously areolate, with few symmetrical pairs of setae and a mid­longitudinal sulcus. Forcipular pleurite homogeneously areolate, with scattered setae and a dorsal longitudinal sclerotised ridge. Coxosternum 1.1 times wider than long; ventral surface homogeneously areolate, with punctuated depressions and scattered setae; dorsal surface not areolate, with evident condylar processes; anterior margin with a pair of stout teeth. Cerrus represented by two lateral groups of 2­4 short setae. Forcipular telopodites mostly not areolate, with punctuated depressions and scattered setae, which are longer on the internal side. Trochanteropraefemur 1.7 times longer than wide; distal tooth poorly evident, proximal tooth absent. Femur virtually lacking a tooth, tibia with a stout tooth. Tarsungulum slender, 0.9 times as long as trochanteropraefemur; most of the distal part dark, internal margin slightly crenate, one obtuse tooth at the basis. Poison calyx cylindrical, asymmetrical, extending from the basis of tarsungulum to the femur.

Leg­bearing segments: 45.

Leg­bearing trunk. First tergum 1.2 times wider and 1.4 times longer than the following tergum. All terga slightly areolate, with few patterned setae and two shallow paramedian sulci. Spiracles from leg­bearing segment II, circular, their diameter decreasing backwards. Pairs of legs 45. Ratio of first leg to second leg 0.8:1; the following legs similar in structure and size, but for the last pair. Sterna of the anterior third of trunk with a tongue­like endosternal process and a mid­longitudinal sulcus, which is not furcate.

Last leg­bearing segment ( Fig. 7 ). Tergum sub­rectangular, 1.2 times longer than wide, 1.6 times longer than the preceding tergum, 0.8 times as wide as the preceding tergum; lateral and posterior margins convex. Praetergum similar to that of the preceding segment. Both tergum and praetergum with scattered setae. Sternum sub­trapezoid, 1.2 times wider than long; lateral margins converging backwards, slightly concave in their posterior halves; posterior margin truncate. Whole surface of sternum covered with setae, more dense on the posterior third. Coxopleura swollen, about as long as tergum and 1.5 times longer than sternum, anteriorly not reaching the spiracles of the preceding segment. Ca. 20 pores on each coxopleuron, on ventral and lateral sides only, diverse in size. Setae scattered on whole coxopleura, much more dense on a pore­less ventral marginal band. Last legs 4.3 times longer than tergum and 2.0 times longer than the preceding legs. Telopodite of six articles, quite swollen, with scattered setae; last four articles similar in length; relatively short setae on the ventral side of the last five articles. Two series of 2­3 spine­like sensilla, internal and external, at the basis of each article. Praetarsus in the shape of a tubercule with two tiny spines.

Terminal segments ( Fig. 7 ). Gonopods not completely developed, apparently uniarticulate, medially in contact, with a few setae. A pair of large anal pores. Last tergum covered with setae, those close to the posterior margin particularly long.

Figures

FIGURES 1 ­ 5. Proterotaiwanella tanabei n. sp., female, 21 mm, holotype. 1, cephalic capsule and right antenna, dorsal; 2, cephalic capsule, ventral; 3, distal part of mandible; 4, right half of maxillary complex, ventral; 5, tip of the second maxillary telopodite, ventral.

FIGURES 6 ­ 7. Proterotaiwanella tanabei n. sp., 6, forcipular segment and right forcipule, dorsal; 7, last leg­bearing segment and terminal segments, ventral (left telopodite and setae on relevant coxopleura not represented). Areolation is drawn only partially but margins of areolate regions are indicated by incomplete lines.

Tables

TABLE 1. Proterotaiwanella tanabei n. sp., female, 21 mm, holotype. Relative length of the antennal articles and number and arrangement of spine­like and button­like sensilla on the same.

Antennal article	I	II	III	IV	V	VI	VII	VIII	IX	X	XI	XII	XIII	XIV
Relative length	10	10	10	10	10	10	9	9	8	8	7	7	7	11
Spine­like sensilla dorsal	4	4	4	4	4	1	4	4	4	1	2	2	2	1
internal­ventral	0	3	3	3	4	0	3	3	3	0	3	3	3	0
external­ventral	0	3	3	3	3	1	3	3	3	1	3	4	4	1
Button­like sensilla dorsal	0	5	0	0	5	0	0	0	4	0	0	0	0	0
ventral	7	5	5	5	7	5	2	2	0	0	0	0	0	0