Piccola latiterga, Gordana & Ambros, 2018

Golovatch, S. I. & Semenyuk, I. I., 2018, On several new or poorly-known Oriental Paradoxosomatidae (Diplopoda: Polydesmida), Arthropoda Selecta 27 (1), pp. 1-21 : 2-5

Piccola latiterga sp.n.

Figs 3 , 6–13 .

HOLOTYPE ♂, Vietnam, Gia Lai Prov., Kon Ka Kinh National Park , N 14°18′08″, E 108°26′41″, 600–700 m a.s.l., mixed tropical forest, steep slope (up to 45°), stream valley, on bush and forest floor, V.2017, leg. I.I. Semenyuk.

PARATYPES: 4 ♂♂, 1 ♀, same data, together with holotype.

DIAGNOSIS. Differs from other Piccola spp. in the presence of a distinct colour pattern and unusually broad and even upturned paraterga, coupled with certain details of solenophore structure.

NAME. To emphasize the unusually broad paraterga; adjective.

DESCRIPTION. Holotype ca 16 mm long, width of midbody pro- and metazonae 1.1 and 2.0 mm, respectively. Paratype ♂♂ ca 18 mm long, width of midbody pro- and metazonae 1.3 and 2.3 mm, respectively. Paratype ♀ ca 17 mm long, width of midbody pro- and metazonae 1.5 and 2.0 mm, respectively. General coloration in alcohol apparently faded, uniformly chocolate brown (♂) or light brown (♀) with a characteristic pattern of more or less strongly contrasting light creamy to nearly pallid paraterga (except for their bases dorsally), vague, much darker creamy, paramedian, roundish spots on pro- and metaterga (divided transversally by dark brown bands near stricture and at metatergal sulci), and pallid tips of antennae ( Figs 6–9 ). Live coloration considerably darker, pattern clear, but not too contrasting ( Fig. 3 ).

Clypeolabral region densely setose, vertigial one bare; epicranial suture thin, but evident ( Fig. 6 ). Antennae long and only slightly clavate, in situ extending until midlength of segment 3 when stretched dorsally (♂); antennomere 2 = 5 = 6> 3 = 4> 1 = 7; interantennal isthmus about 1.3 times as broad as diameter of antennal socket.

In width, head <collum <segment 2 = 3 <segment 4 <5–16; thereafter body gradually tapering towards telson. Tegument mostly shining; prozonae finely shagreened; metaterga striolate (largely near bases of paraterga) and roughly longitudinally striate in rear halves; surface below paraterga almost dull and clearly granulate. Collum broadly rounded laterally, with small, subhorizontal, rounded paraterga. Postcollum paraterga very strongly (♂) or only moderately (♀) developed, mostly set at about upper 1/4 (♂) or 1/3 (♀) of body height, broad, slightly, but obviously upturned (♂) ( Figs 6–9 ) or faintly declined and lying well below a clearly convex dorsum (♀) ( Fig. 3 ), delimited from callus by a complete distinct sulcus both dorsally and ventrally ( Figs 6, 8, 9 ); anterolateral corner always very broadly and regularly rounded, caudolateral clearly rounded and acute-angled on segments 2–5, rounded and subrectangular until segment 11, increasingly acute-angled and sharpened thereafter, but especially sharp and drawn back behind rear tergal margin only in segments 14–19 (♀) or 16–19 (♂). Poriferous calluses somewhat thicker than poreless ones, slightly, but clearly sinuate at abour ozopore level; all calluses devoid of lateral incisions and extending dorsally into smaller ridges along both anterior and caudal margins of paraterga so that the latter slightly impressed; ozopores dorsolateral, partly visible from above, lying inside an ovoid groove at about 1/3 of metatergal length off caudolateral corner ( Figs 8, 9 ). Transverse metatergal sulcus faint and incomplete on segments 4 and 19, deeper, finely beaded at bottom, complete and reaching the bases of paraterga on segments 5–18 ( Figs 8, 9 ). Tergal setae mostly abraded, about 1/3–1/2 as long as metaterga, setation pattern untraceable, but setae arranged in two transverse rows. Stricture dividing pro- and metazonae thin and deep, clearly beaded at bottom down to level of paraterga where stricture growing striolate. Pleurosternal carinae evident, but low lobes only on segments 2 and 3, thereafter missing. Axial line mostly inconspicuous, traceable only on metaterga ( Figs 8, 9 ). Epiproct ( Figs 6, 9 ) long, conical, subtruncate at apex, subapical lateral papillae small, but evident; a pair of small, apical, ventrally directed claws placed at tip. Hypoproct roundly subtriangular, caudal 1+1 setae well-separated, borne on minute knobs.

Sterna sparsely setose, without modifications except for a pair of very small, rounded, independent, setose knobs between coxae 4 (♂); cross-impressions faint. Adenostyles missing. Legs long, slender, either slightly incrassate (♂) or shorter and more slender (♀),>2.0 (♂) or 1.1–1.2 times (♀) as long as midbody height; in length, femora >> tibiae = tarsi> prefemora = postfemora = coxae; claw very small; coxae and prefemora often finely papillate laterally, the latter not swollen ( Fig. 10 ). Tarsal brushes distinct, present on all legs, but largely covering only distal half to third (♂).

Gonopods ( Figs 11–21 ) rather simple, in situ held parallel to each other; coxite short, slender, subcylindrical, setose distoventrally, about half as long as femorite (fe); telopodite slender, suberect; prefemoral (= densely setose) region ca 1/3 as long as acropodite; fe not twisted, clearly excavate on mesal face, bearing a distinct, oblique, ventromesal ridge (r) all along, set off from solenophore (sph) by a mainly lateral sulcus (s); fe about as long as sph, only slightly broadened apically, with a seminal groove (sg) running entirely on mesal face before almost level with s; distodorsally passing onto a free solenomere (sl), the latter almost as long as sph, flagelliform, its distal part lying inside a mesal fold (f) of an apically broadened and axe-shaped sph, leaving sl tip at most barely exposed.

REMARKS. At present, the rather small genus Piccola Attems, 1936 , tribe Orthomorphini , encompasses only seven species, one each in Laos and southern China (the sole presumed troglobite), and the remaining five in Vietnam [ Liu, Tian, 2015]. The new species is quite disjunct in showing unusually prominent, even slightly upturned paraterga. The diagnosis of this genus can now be somewhat emended in its main characteristics being typical orthomorphine, slender, more or less suberect gonopods, each femorite (fe) of which is mesally excavate, mostly shows a conspicuous, oblique, ventral ridge (r) and carries the seminal groove (sg) entirely on its mesal side, while the solenophore (sph) sometimes fails to have clear-cut lamellae, is more or less axe-shaped apically and demarcated basally from the femorite by only a single sulcus (s) (a postfemoral part/sulcus is thus missing), and the solenomere (sl) is flagelliform, about as long as the solenophore and sheathes it completely or nearly so.

Figures

Figs 3–5. Live coloration of Piccola latiterga sp.n., ♀ paratype, Enghoffosoma extraspinosum sp.n., ♂ holotype, and Touranella moniliformis sp.n., ♂ holotype, respectively. Pictures by I. Semenyuk. Рис. 3–5. ПрижиЗненнаЯ окраска соответственно Piccola latiterga sp.n. (паратип ♀), Enghoffosoma extraspinosum sp.n. (голотип ♂) и Touranella moniliformis sp.n. (голотип ♂). Фотографии И. Семенюк.

Figs 6–9. Piccola latiterga sp.n., ♂ paratype. 6 — habitus, lateral view; 7 — anterior part of body, ventral view; 8 — midbody segments, dorsal view; 9 — caudal part of body, dorsal view. Pictures by K. Makarov, not taken to scale. Рис. 6–9. Piccola latiterga sp.n., паратип ♂. 6 — обЩий вид, сбоку; 7 — переднЯЯ часть тела, сниЗу; 8 — среднетуловиЩные сегменты, сверху; 9 — ЗаднЯЯ часть тела, сверху. Фотографии К. Макарова, снЯты беЗ масШтаба.

Figs 10–13. Piccola latiterga sp.n., ♂ paratype. 10 — leg 7, lateral view; 11–13 — left gonopod, lateral, ventral and mesal views, respectively. Scale bar: 0.5 mm. Designations explained in text. Del. S. Golovatch. Рис. 10–13. Piccola latiterga sp.n., паратип ♂. 10 — нога 7, сбоку; 11–13 — левый гонопод, соответственно сбоку, сниЗу и иЗнутри. МасШтаб: 0,5 мм. ОбоЗначениЯ обЪЯснены в тексте. Рисунки С. Головача.