Polycricus roigi Pereira, 2016, sp. nov.
Creators: name: Pereira, Luis Alberto
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Chilopoda
Geophilomorpha
Geophilidae
Polycricus
Polycricus roigi

description: Plateurytion roigi sp. nov.
(Figs. 1–50)
Diagnosis. A species of Plateurytion characterized by having the following features: coxosternite of first maxillae without lappets; sclerotized rim of coxosternites of second maxillae not elongated; ventral pore-fields present in an uninterrupted series all along the trunk; all coxal organs distinct and open separately; dorsal side of coxopleura of the ultimate leg-bearing segment devoid of coxal pores. Of the other South American species currently included in the genus, only the present new species and P. gracilis (Gervais, 1849) share all these combined characters. Plateurytion roigi can be confidently differentiated from P. gracilis by means of the following selected traits (the corresponding ones in the latter are given in parentheses): body length of female 18 mm (40 mm); female with 43 leg-bearing segments (with 67 leg-bearing segments); undivided pore-fields of anterior region of the body extended up to ca. metasternite 11 (up to ca. metasternite 25); coxal pores dispersed on ventral and lateral surfaces of coxopleuron, Figs. 46, 47 (restricted along the membrane between coxopleuron and metasternite); anal organs present, Figs. 46: c, 50: b (absent).
Remarks. Other morphological traits included in Table 1 differentiate P. ro i gi sp. nov. from P. gracilis.
Type material examined. CHILE: Region X (de Los Lagos region): Palena province: Chaitén: El Amarillo, December 12, 1986, S. A. Roig-Juñent coll.: holotype ♀ with 43 leg-bearing segments, body length 18 mm, in ethanol, head detached from trunk (MLP-Ar 19441).
Depository of type. MLP-Ar.
Description. Female holotype (adult). General features. Forty three leg-bearing segments, body length 18 mm, maximum body width 0.70 mm, maximum width of cephalic plate 0.54 mm, length of cephalic plate 0.72 mm, maximum width of forcipular coxosternite 0.70 mm. Colour (of preserved specimen in ethanol): forcipular segment bright ferrugineous, rest of the body pale orange-brownish.
Antennae. About 2.90 times as long as the cephalic plate, ratio of width of a.a. II/width of a.a. XIV 1.55: 1. A.a. I nearly as long as wide, remaining a.a. longer than wide. Length/width ratio of a.a. XIV 2.05: 1. Ventral chaetotaxy: setae on a.a. I-VII of various lengths and relatively few in number, those on a.a. VIII-XIV progressively shorter and more numerous towards the tip of the appendage (Fig. 1). Dorsal chaetotaxy: setae slightly shorter and less numerous than on ventral side. A.a. XIV with 13 claviform sensilla on the external margin and 12 on the internal margin (Fig. 2: a); distal end of this a.a. with ca. 5 – 6 very small hyaline specialized sensilla not split apically (Fig. 2: b). Ventral and dorsal surface of a.a. II, V, IX and XIII with very small specialized sensilla. Ventrally, sensilla restricted to a middle and apical latero-internal area (Figs. 3–6), and represented by two different types: a and b. Type a sensilla very thin, not split apically (Fig. 5: a); type b sensilla (Fig. 5: b) thicker and very similar to those of the apex of a.a. XIV. Specialized sensilla on dorsal side restricted to a middle and apical latero-external area (Figs. 7 – 10) and represented by two different types: a similar to a of ventral side, but proportionally much shorter (Fig. 10: a), and b similar to b of ventral side (Fig. 10: b). Number and distribution of specialized sensilla on ventral and dorsal sides of a.a. II, V, IX and XIII, as in Table 2.
A.a. Ventral Dorsal Figs.
a b a b
II – 1 1 1 3, 7 V 1 1 1 1 4, 8 IX 1 1 1 2 5, 9 XIII 1 1 1 3 6, 1 0
Remarks. The original source for the nomenclature of specialized sensilla, is Pereira et al. (1995).
Cephalic plate. Distinctly longer than wide (length/width ratio ca. 1.30: 1), without a distinct frontal sulcus. Anterior margin very slightly concave at middle; lateral margins slightly convex; posterior margin slightly concave; anterior and posterior sides, curved. Shape and chaetotaxy as in Fig. 11.
Clypeus. Four setae located on the clypeal area; posteriorly accompanied by 1 + 1 setae at either side (Fig. 12). Clypeal area with surface minutely punctate or granulate not areolate (Figs. 12: a, 13).
Labrum. Mid-piece slightly pigmented, well-developed with 10 short distinct teeth. Side-pieces with ca. 13 + 16 hyaline filaments (Fig. 14).
Mandible. Pectinate lamella with ca. 14 hyaline teeth.
First maxillae. Coxosternite without lappets, telopodites with small lappets (Fig. 15: a). Coxosternite devoid of setae; coxal projections subtriangular, well-developed, round tipped and provided with 2 + 2 large setae and 4 + 4 small setae (Fig. 16). Apical article of telopodites with 2 + 3 setae on ventral side (Fig. 16).
Second maxillae. Coxosternites medially joined through a narrow, hyaline and non-areolate membranous isthmus only, and with 8 + 8 setae near the internal margins (Fig. 16). Antero-internal corners of coxosternites without processes (Fig. 16). Metameric pores accompanied by a sclerotized, not elongated rim (Figs. 16: c, 17: b).
Articles of telopodites without distoectal processes; apical claw well-developed, a little shorter than the third article, shape as in Figs. 16, 18. Chaetotaxy of coxosternite and telopodites as in Fig. 16.
Forcipular segment. Telopodites, when extended, almost attaining the end of a.a. II (Fig. 11). Forcipular tergite trapeziform, anterior and posterior margins respectively covered by the cephalic plate and the tergite of the first leg-bearing segment; chaetotaxy represented by ca. 14 large and short setae distributed as in Fig. 11. Coxosternite without chitin-lines, middle part of anterior margin slightly notched and concave, provided with 1 + 1 slightly pigmented denticles bearing 1 + 0 dorsal small setae, aspect and relative size as in Figs. 19, 21. Telopodites: medial edge of trochanteroprefemur with two teeth, both deeply pigmented, relative size and shape as in Figs. 19 – 21; ratio width of trochanteroprefemur at level of distal basal part of apical tooth/width of trochanteroprefemur at level of distal basal part of proximal tooth ca. 0.87: 1. Femur and tibia without denticles. Tarsungulum basally with a welldeveloped, round tipped and deeply pigmented subtriangular tooth (Figs. 19, 21); ventral and dorsal medial edges of forcipular tarsungulum not serrate, ventral edge very slightly crenulate (Figs. 19, 21). Relative size of poison glands as in Figs. 21, 22: a; calyx of poison gland subtriangular in shape (Figs. 21, 22: b, 23: a). Chaetotaxy of coxosternite and telopodites as in Fig. 19.
Metasternites of leg-bearing segments 1 to penultimate. Pore-fields present in an uninterrupted series from metasternite 2 to penultimate inclusive, fields undivided on metasternites 2 – 11, uncompletely divided on metasternite 12 (Fig. 30), divided in two subsymmetrical areas on metasternites 13 – 42. Shape and relative size of pore-fields changing along the trunk as in Figs. 24–36. Number of pores on selected metasternites as follows: metasternite 2 (15 pores); 3 (31); 6 (41); 9 (36); 10 (43); 11 (40); 12 (36); 13 (15 + 18); 17 (11 + 8); 21 (5 + 7); 30 (5 + 7); 36 (8 + 9); 42 (6 + 5).
Legs (pair 1 to penultimate). Ratio of length of first pair/length of second pair ca. 0.79: 1 (relative size as in Figs. 37, 38). Chaetotaxy similar throughout the whole body length (Figs. 37–41). Claws with two thin and pale accessory spines ventrobasally, one anterior (Figs. 42–44: a) and one posterior, shorter (Figs. 42 – 44: b).
Ultimate leg-bearing segment. Intercalary pleurites absent at both sides of the ultimate pretergite; ultimate presternite not divided along the sagittal plane; length/width ratio of metatergite 0.86: 1; length/width ratio of metasternite 0.76: 1. Shape and chaetotaxy of metatergite and metasternite as in Figs. 45, 46. Coxopleura slightly protruding at distal-internal ventral ends, setae small and numerous distributed on the internal ventral area, the remaining coxopleural surface with few small and larger setae (Figs. 45, 46). Coxopleura with 9 + 10 single (“homogeneous” sensu Brölemann & Ribaut 1912) coxal organs, opening independently; a few coxal pores placed near the membrane between coxopleuron and metasternite, partially covered by the latter, remaining ones dispersed on ventral and lateral surfaces (Figs. 46, 47), dorsal side of coxopleura devoid of coxal pores (Fig. 45); internal cuticular structure of coxal organs as in Fig. 47 (a: mucous layer, b: contour of lobe). Telopodites of ultimate legs with six articles, shape and chaetotaxy as in Figs. 45, 46. Length of telopodites of ultimate legs/length of metasternite ca. 4.21: 1. Ultimate pretarsus unguiform, bearing a single internal spine ventrobasally (Figs. 48, 49: a).
Postpedal segments. Intermediate tergite with posterior margin strongly convex, bearing numerous small and large setae (Fig. 45); intermediate sternite seemingly covered by the metasternite of the ultimate leg-bearing segment; posterior margin of first genital sternite slightly concave (Fig. 46). Gonopods uniarticulate not separated on the middle line (Figs. 46: b, 50: a). Anal organs present (Figs. 46: c, 50: b).
Male. Unknown.
Etymology. The new species is respectfully dedicated to the collector of the type specimen Dr. Sergio Alberto Roig-Juñent, researcher of the CONICET, working at the Instituto Argentino de Investigaciones de las Zonas Aridas (IADIZA), Mendoza, Argentina.
Ecology. The holotype was collected in the soil, at about 800 m a.s.l., in a temperate rain forest environment, the Valdivian forest, which occurs on the west coast of southern South America, lying mostly in Chile extending into small parts of Argentina, from roughly 37° to 48° south latitude. (Details on altitudinal levels, floristic, and faunal components of this forest, can be consulted in Cabrera and Willink 1973; Morrone 2015).
Type locality. See above.
Known range. Only known from the type locality.
description: Published as part of Pereira, Luis Alberto, 2016, Plateurytion roigi sp. nov., a new geophilid centipede (Myriapoda: Chilopoda: Geophilomorpha) from Southern Chile, pp. 347-360 in Zootaxa 4162 (2) on pages 348-356, DOI: 10.11646/zootaxa.4162.2.9, http://zenodo.org/record/272333