Megaphyllum (Parancistrum) arcuatum, Vagalinski, Boyan, Lazányi, Eszter & Golovatch, Sergei, 2013

Vagalinski, Boyan, Lazányi, Eszter & Golovatch, Sergei, 2013, Redescription of the subgenus Parancistrum Verhoeff, 1943, an eastern Mediterranean lineage of the millipede genus Megaphyllum Verhoeff, 1894 (Diplopoda: Julida: Julidae: Brachyiulini), Zootaxa 3734 (5), pp. 501-520 : 514-517

Megaphyllum (Parancistrum) arcuatum sp. n.

Figs 41–55

Holotype. (ZMTA) ( Figs 41–43 ): 1 ♂ (intact), Adolam Nature Reserve, nr. Beit Gurvin, pitfall trapping, No. 16(8), XI.2001, Y. Mandelik leg., SG det.

Paratypes. (ZMUC): 2 ♂♂ (one intact, the other in head-collum+ first 2 body rings +3rd– 6th body rings + rest of body, gonopods dissected, 1 half prepared for SEM), 2 ♀♀ (one unbroken, the other fragmented, with dissected vulvae), 2 juv. ♂♂, Israel, Segev, X.1994, leg. M. Warburg; (ZMUM): 1 ♂ (intact), Israel, Sdot Micha, pitfall traps, No. 45(12), XI.2001, leg. Y. Mandelik; (NMNHS): 1 ♂ (unbroken), Israel, Adolam Nature Reserve, nr. Beit Gurvin, pitfall trapping, No. 18(7), XI.2001, Y. Mandelik leg., SG det.; (HNHM): 1 ♂ (intact), Israel, Adolam Nature Reserve, nr. Beit Gurvin, pitfall trapping, No. 17(4), XI.2001, Y. Mandelik leg., SG det.; (ZMTA): 1 ♀ (intact), Israel, Adolam Nature Reserve, nr. Beit Gurvin, pitfall trapping No. 16(3), XI.2001, Y. Mandelik leg., SG det.

Other material. All from Israel, pitfall trapping: ZMTA: From Sdot Micha: 1 ♂, No. 42 A(6), XI.2001, Y. Mandelik leg., SG det.; 1 ♂, 2 ♀♀, No. 45(7), Y. Mandelik leg., SG det. From Ramot Avishur, nr. Beit Gurvin: 1 ♂, No. 24(8), XI.2001, Y. Mandelik leg., SG det.; 1 ♂, No. 28(10), XI.2001, Y. Mandelik leg., SG det.; Adolam Nature Reserve, nr. Beit Gurvin: 1 ♂, No. 4(9), road; 1 ♂, No. 16(9), road; 1 ♂, No. 6(10), road; 1 ♀, No. 14(10); 1 ♀, No. 4(6). ZMUC: 1 ♂, Segev, Lower Galil, 1994, M. Warburg leg., H. Enghoff det. as cf. tenenbaumi ; 1 ♂, 1 ♀, Segev, Lower Galil, 29.I.1986, M. R. Warburg leg. & ded., H. Enghoff det. as cf. tenenbaumi .

Diagnosis. Differs from M. serratum and M. turcicum by the smooth, rather than serrated, anterior opisthomere process; from M. curvifolii and M. genezarethanum by the apically incised, rather than rounded, promere; and from M. tenenbaumi by the anterior solenomere protrusion being slenderer, tapering and turned posteriad, as opposed to the same process being short, blunt and pointing distad in the latter species, as well as by the promere’s apical incision being considerably more shallow than in M. tenenbaumi .

Name. To emphasize not only the fact that the entire gonopod is clearly bent caudad, like in the above two species plus M. curvifolii , but also the arcuate anterior solenomere protrusion (asp), which is unique in the subgenus.

Description. Measurements: holotype ♂ in stadium XI, 53+1+T, length 37 mm, height 2.1 mm. Paratype ♂♂ (ZMUC): in stadium XI, 53+1+T, length 34 and 31 mm, height 2.1 and 2.2 mm respectively; (ZMUM): in stadium XI, 52+2+T, length 30 mm, height 1.9 mm; (NMNHS): in stadium XI, 54+1+T, length 42 mm, height 2.2 mm; (HNHM): in stadium XI, 51+1+T, length 35 mm, height 2.1 mm. Paratype ♀♀ (ZMUC): in stadium XII, 55+1+T, length 37 mm, height 2.9 mm and 3.1 mm; (ZMTA): in stadium XI, 51+1+T, length 31 mm, height 2.1 mm.

Coloration: Overall brownish ( Fig. 41 ); head ( Fig. 42 ) dark brown with a black band between ocellaria; collum dark brown with blackish margins; metazona castaneous brown with ochre-brown hind margins; prozona irregularly striped light and dark brown; a dark grey, continuous, mid-dorsal stripe divided by a black axial line, and two blackish, broken, dorsolateral stripes at ozopore level.

External structures: 2 frontal, 4 supralabral and 22 labral setae. Antennomeres 5, 4 and 3 subequal in length. Gnathochilarium typically julid, with 3 apical setae on each stipes and 4–5 setae on each lingual plate; promentum relatively large, length to width ratio: 1.9–2.1. Collum smooth, with only one long stria running parallel to anterolateral margin. Prozona with numerous short, parallel scratches; metazona densely striated, with 10–11 striae in a square with sides equal to metazonal length just below ozopore level; a moderately dense row of erect setae ca 1/2–2/3 of metazonal length at metazonal hind margin. Ozopores placed just behind suture between pro- and metazona, suture slightly sinuous in front of them around midbody and further behind. Tarsi of midbody legs slightly shorter than to equal to tibiae. Pre-anal process long, straight, surpassing the longest setae on anal valves, with a well-developed ventral keel and a distinct, thin, pointed, hyaline tip turned slightly ventrad (broken off in most specimens). Subanal scale triangular, pointed, protruding by about its distal quarter behind rear contour of anal valves in males, blunt, not protruding in females. Anal valves moderately densely pilose, without distinct rows of shorter setae along caudal margin ( Fig. 43 ).

Male sexual characters: Mandibular stipites enlarged (arrow in Fig. 42 ), ellipsoid or egg-shaped, equally protruding ventrad and anteriad, with a regularly convex ventral margin and a straight to slightly concave anterior margin, forming no distinct anterior corner. Leg-pair 1 normal parallel hooks with somewhat diverging tibial outgrowths; tarsal remnants not evident. Leg-pair 2 with two simple adhesive pads, one each on postfemur and tibia. Pleurotergum 7 ventrally with large, trowel-shaped lobes protruding entirely mesad and closing gonopod sinus from behind. Walking legs with pads on femur, postfemur and tibia; femoral pads strongly flattened, gradually diminishing in size towards telson. Penis ( Figs 46–47 ) longer than broad, with parallel, tightly contiguous, somewhat posteriad turned, apical lobes about half as long as penis, ending up with small, rounded, terminal lamellae.

Gonopods: Promere ( Figs 49–50 and P in Fig. 48 ) ca 3 times longer than broad, more or less regularly wide until a laterally sloping, gently incised apex; median ridge (r) prominent, robust, rather short; median groove (g) broad and rather deep. Flagellum (fl in Figs 48–49 ) somewhat longer than promere, thin. Opisthomere ( Figs 48, 52–54 ) slender, basally somewhat curved posteriad, with a well-detached, parallel, posterior process (pp) whose distal part is slightly widened, ending up in a thick, rounded margin and bearing several small humps; and a slender, tapering, somewhat dorsoventrally compressed, anterior process (ap). Solenomere (s) well-differentiated from main opisthomere body through a neck-like constriction (c in Fig. 52 ), bulging anteriorly, ending up by an anterior lamellar protrusion (asp) with a pointed, posteriad curved tip. Spine-like filaments (sf) along flagellum channel (fc) present. Gonopods in situ: largely external, protruding posteriad to reach coxae 12 ( Fig. 42 ); solenomere slightly overreaching promere ( Fig. 48 ). Promere-promere connection stronger than promereopisthomere one, promeres fused basally at a nearly right angle ( Fig. 49 ), partly covering opisthomeres laterally.

Female sexual characters: Leg-pair 2 and, especially, pair 1 of mature females somewhat enlarged. Vulvae ( Figs 44–45 , 55 ) cylindrical, almost completely symmetric, lateral valve of bursa distally protruding into a more prominent hump (lh) than mesal (mh) one. Bursa forming a distinct, subrectangular, apical margin. Opening (o) small, slit-like, placed just on top of bursa; bursal sidelobes ending by large, rounded, hyaline protrusions (bl). Operculum (op) narrow, subequal in height to bursa, ending up by a bifurcated hyaline protrusion. Receptaculum seminis double, consisting of a wide apodematic tube (at) ending with a short, finger-like reservoir and a globular posterior ampulla (pa) joining at just before the opening through a thin, spirally folded, connecting tube (ct).

Distribution. The species seems to be endemic to Israel.

Remarks. The new species shows more similarities to M. tenenbaumi than to M. genezarethanum due to the more or less clearly incised promere apex, as well as the angled connection between both promeres and the more robust, mesolaterally less strongly compressed vulvae.

Figures

FIGURES 41 – 45. Megaphyllum arcuatum holotype male (40 – 42) and paratype female from Segev (43 – 44): (41) habitus (not to scale); (42) head with anterior body rings; (43) telson with last three body rings; (44) left vulva, posterior view; (45) right vulva, lateral, slightly posterior view (setae omitted, receptaculum seen by transparency, but drawn with solid lines for better emphasis). Abbreviations: at: apodematic tube, bl: bursal lamellar protrusions, ch: central hump, ct: connecting tube lh: lateral hump, mh: mesal hump, o: opening, op: operculum, opl: operculum’s lamellar protrusions, pa: posterior ampulla, ph: posterior hump. Scale bars: 0.3 mm (Fig. 44) and 0.2 mm (Fig. 45).

FIGURES 46 – 54. Megaphyllum arcuatum paratype male (46 – 47; 49 – 40; 52 – 54) from Segev and non-type male (48, 51) from near Beit Gurvin: (46) and (47) penis, caudal and lateral views, respectively; (48) right gonopods, mesal views; (49) joint promeres, posterior view; (50) left promere, posterior view (51) left opisthomere, lateral view; (52) distal part of right opisthomere, mesal view; (53) distal part of right opisthomere, postero-mesal view; (54) distal part of right opisthomere, anterior view. Abbreviations: ap: anterior process, asp: anterior protrusion of the solenomere, c: neck-like constriction, fc: flagellum channel, fl: flagellum, g: median groove, P: promere, pp: posterior process, r: median ridge, s: solenomere, sf: spine-like filaments. Scale bars of the drawings: 0.2 mm.

FIGURES 55 – 57. Schematic bursal contours of left vulvae in posterior view of (55) M. arcuatum, (56) M. tenebaumi and (57) M. genezarethanum. Abbreviations: ch: central hump, lh: lateral hump, mh: mesal hump. Scale bar: 0.2 mm.