Chilerium zapallar

Redescription. Male (specimen MACN-My 29). Fifty-one leg-bearing segments, body length 25 mm, maximum body width 1.32 mm. Maximum width of cephalic plate 0.73 mm, length of cephalic plate 1.12 mm, maximum width of forcipular coxosternite 1.00 mm. Ground color (of preserved specimen in alcohol) yellowish, forcipular segment darker (pale ochreous). Antennae. Relatively short, ca. 2.64 times as long as the cephalic plate, distally attenuate (Fig. 54). Ratio of width of a. a. II / width of a. a. XIV ca. 2.04: 1; all a. a. longer than wide. Ventral chaetotaxy: setae on a. a. I – VI of various lengths and relatively few in number, those of a. a. VII – XIV progressively shorter and more numerous towards the tip of the appendage (Fig. 54). Dorsal chaetotaxy: setae on a. a. I – VI similar to the ventral side, setae on remaining a. a. a little longer and slightly less numerous. A. a. XIV with ca. 13 claviform sensilla on the external margin and ca. 9 on the internal margin (Fig. 55: a); distal end of this a. a. with ca. 4 – 5 very small hyaline specialized sensilla not split apically (Fig. 55: b). Ventral and dorsal surface of a. a. II, V, IX and XIII with very small specialized sensilla. On the ventral side these sensilla are placed in the internal latero-apical area and are represented by two different types: a and b. Type a sensilla are very thin and not split apically (Fig. 58: a); type b sensilla (Fig. 58: b) are very similar to those on the apex of a. a. XIV but having two diminutive apical branches. Specialized sensilla on dorsal side restricted to a middle and external latero-apical areas and are represented by three different types: type a, similar to type a of ventral side (Fig. 59: a), type b sensilla not split apically and similar to those on the apex of a. a. XIV (Fig. 59: b), and type c sensilla similar in shape to the latter, a little larger, not divided apically and slightly darker (pale brownish-ochreous in color) (Fig. 59: c). Number and distribution of specialized sensilla on ventral and dorsal sides of a. a. II, V, IX and XIII, as in Table 3. Ventral Dorsal Figs. a b a b c II – 1 – 1 – V 1 1 1 1 – IX 1 1 1 1 1 56, 57 XIII 1 1 1 3 1 58, 59 Cephalic plate. Distinctly longer than wide (length / width ratio ca. 1.48: 1). Middle part of lateral margins convergent towards the posterior region; anterior margin convex at middle, slightly concave at level of the bases of the antennae; posterior margin nearly straight; anterior and posterior sides, curved. Shape and chaetotaxy as in Fig. 60. Clypeus. With 1 + 1 setae adjacent to the anterior margin of the clypeal area, two setae located on it (Fig. 62), posterior to the latter 2 + 2 setae distributed at both sides of the middle line (Fig. 61). Clypeal area well developed with surface minutely punctuate or granulate, not areolate (Fig. 62). Labrum. Mid-piece well developed, subtriangular in shape, slightly pigmented and provided with 13 hyaline and thin filaments (Figs. 63, 64). Side pieces with 17 + 17 hyaline filaments of different sizes (Fig. 63). Mandible. With shape as in Fig. 65, pectinate lamella with ca. 22 hyaline teeth. First maxillae. Coxosternite and telopodites with very well developed lappets (Fig. 66). Coxosternite devoid of setae; coxal projections subtriangular, round-tipped and provided with 6 + 6 setae and 2 + 2 very small sensilla (Fig. 66). Article II of telopodites with 7 + 5 large setae on ventral side (Fig. 66), and 1 + 1 small sensilla on dorsal side. Second maxillae. Coxites medially joined through a narrow, hyaline and non-areolate membranous isthmus only and provided with 8 + 8 setae near the internal and antero-internal borders and 2 + 2 setae near the external borders (Fig. 66). Metameric pores accompanied by a sclerotized rim with shape as in Fig. 66: c. Apical claw of telopodites well developed (Fig. 66). Chaetotaxy of coxosternites and telopodites as in Fig. 66. Forcipular segment. When extended the telopodites attaining the middle part of the a. a. II. Forcipular tergite trapeziform (Fig. 62: a), with anterior and posterior margins respectively covered by the cephalic plate and the tergite of the first leg-bearing segment; chaetotaxy represented by 1 + 1 large setae and ca. 17 + 17 very small setae with relative size and distribution as in Fig. 68. Coxosternite without chitin-lines, middle part of anterior border conspicuously notched and strongly concave, provided with 1 + 1 slightly pigmented denticles, the left one bearing a dorsal seta; aspect and relative size as in Figs. 67, 69. Telopodites: medial edge of trochanteroprefemur with a proximal and a distal tooth, both deeply pigmented (Figs. 67, 69). Femur and tibia without denticles. Tarsungulum basally with a well developed and deeply pigmented subtriangular tooth (Figs. 67, 70); ventral medial edge of tarsungulum not serrate (Figs. 67, 70). Relative size of poison gland as in Fig. 70, calyx of poison gland subtriangular in shape (Figs. 70 – 72). Chaetotaxy of coxosternites and telopodites as in Figs. 67, 69. Metasternites of leg-bearing segments 1 to penultimate. With a median shallow longitudinal sulcus all along the body length. Pore-fields present in an uninterrupted series from metasternite 1 to penultimate inclusive; fields undivided on metasternites 1 – 15 (Figs. 73 – 79), divided in two subsymmetrical areas on metasternites 16 – 50 (Figs. 80 – 85). Metasternites 4 (Fig. 75); 6; 7 (Fig. 76); 8; 9; 10 (Fig. 77); 11; 12 (Fig. 78); 13 (Fig. 79); 14; 15; 16 (Fig. 80); 17; 18 (Fig. 81); 19 – 24; 26; 34; 37 – 43; 45; 46 (Fig. 83); and 47 with ca. 1 – 5 additional dispersed pores near one or both lateral margins. Number of pores on selected metasternites as follows: metasternite 1 (6); 2 (53); 4 (1 + 71 + 0); 7 (2 + 99 + 0); 10 (2 + 97 + 3); 12 (2 + 106 + 5); 13 (2 + 99 + 3); 16 (4 + 41 + 44 + 4); 18 (3 + 31 + 34 + 3); 32 (11 + 11); 46 (1 + 15 + 14 + 0); 49 (10 + 16); 50 (9 + 6). Chaetotaxy of metasternites, shape and relative size of pore-fields as in Figs. 73 – 85. Legs (pair 1 to penultimate). Ratio of length of first pair / length of second pair ca. 0.80: 1 (relative size as in Figs. 86, 87). Chaetotaxy similar throughout the whole body length; distribution, number and relative size of setae as in Figs. 86 – 91. Claws with two thin and pale accessory spines ventrobasally, the anterior (Figs. 92, 93: a) bigger than the posterior (Figs. 92, 93: b). Ultimate leg-bearing segment. Intercalary pleurites absent at both sides of the ultimate pretergite (Fig. 94); ultimate presternite not divided along the sagittal plane (Fig. 95). Length / width ratio of metatergite, ca. 0.87: 1; length / width ratio of metasternite, ca. 0.79: 1. Shape and chaetotaxy of metatergite and metasternite as in Figs. 94, 95. Coxopleura strongly protruding at their distal-internal ventral ends, setae small and numerous on the internal ventral area, the remaining coxopleural surface with much less numerous setae of different lengths (Figs. 94, 95). Each coxopleuron with all coxal organs grouped in a cluster opening on the membrane between coxopleuron and metasternite, partially or totally covered by the latter (Figs. 95, 96). Right cluster with 11 organs; left cluster with 10 organs; arrangement of organs in each cluster as in Fig. 96. Telopodites of ultimate legs composed of six conspicuously inflated articles. Ratio of length of telopodites of ultimate legs / length of metasternite ca. 3.98: 1. Shape and chaetotaxy of ultimate legs as in Figs. 94, 95. Ultimate pretarsus unguiform, relatively smaller than those of the preceding legs, bearing a single very small and hyaline internal spine ventrobasally. Postpedal segments. Intermediate tergite with posterior margin strongly convex (Fig. 94), intermediate sternite with posterior margin nearly straight (Fig. 95). Posterior margin of first genital sternite concave (Fig. 95). Gonopods apparently uniarticulate (suture between the presumptive basal and distal articles not evident), bearing ca. 25 setae (Fig. 97); penis dorsally with 3 + 3 apical setae (Fig. 98). Anal organs absent. Female (specimen MACN-My 25). Forty-seven leg-bearing segments, body length 26 mm, maximum body width ca. 1.25 mm. Features similar to those in the male, except for the shape and pilosity of the ultimate legbearing segment and postpedal segments. Ultimate leg-bearing segment. Length / width ratio of metatergite 0.65: 1; length / width ratio of metasternite 0.72: 1. Shape and chaetotaxy of metatergite and metasternite as in Figs. 108, 109. Coxopleura conspicuously protruding at their distal-internal ventral area, setae small and numerous on the internal ventral area, the remaining coxopleural surface with much less numerous setae of different lengths (Figs. 108, 109). Right and left cluster of coxal organs with ca. 11 organs (Fig. 109). Articles of ultimate legs inflated. Ratio of length of telopodites of ultimate legs / length of metasternite ca. 4.23: 1. Shape and chaetotaxy as in Figs. 108, 109. Postpedal segments. Intermediate tergite with posterior margin convex (Fig. 108); intermediate sternite with posterior margin slightly concave, (Fig. 109); posterior border of first genital sternite very slightly convex (Fig. 109). Gonopods uniarticulate, not separated on the middle (Fig. 109). Anal organs absent. Variation. Females with 47, 49, (probably 51), 53 leg-bearing segments; males with 47, 49, 51. All other characters without significant variation.

Diagnosis. A species of Plateurytion characterized by having one cluster of coxal organs in each coxopleuron of the ultimate leg-bearing segment. Of the other South American species currently included in the genus, only the present species and P. mundus (Chamberlin, 1955) share the same character. Plateurytion zapallar can be confidently differentiated from P. mundus by means of the characters used in the preceding diagnosis of the latter. Other morphological traits included in Table 1 differentiate P. zapallar from P. mundus.

Remarks. According to the biogeographical regionalization of the Andean Region proposed by Morrone (2015), the geographical distribution of this species corresponds to the " Coquimban province " and " Santiagan province " (Central Chilean sub-region).

Remarks. An accurate comparison of the characters of specific value in the lectotype male (Figs. 99 – 104) and paralectotype female (Figs. 105 – 107), with those of the specimens cited in " Other material examined " (Figs. 54 – 98, 108, 109) leave no doubts as to the conspecificity of all of them. The precedent redescription of P. zapallar is based on the non-type specimens, because the lectotype male is incomplete and the paralectotype female shows a sub-adult condition, indicated by the relatively small body size, empty spermathecae (located at level of the penultimate leg-bearing segment), low number of organs in each cluster of coxal organs and reduced pilosity on the articles of ultimate legs. Plateurytion zapallar was inadequately described by Chamberlin; his original description does not refer to a specimen in particular, nor does it specify the sex of the studied specimens. It only includes a single inaccurate figure of the cephalic plate, and completely lacks information on pilosity of the antennae; kind and number of specialized sensilla of a. a. II, V, IX and XIII; shape of mandibles; anterior and posterior limits of ventral porefields; shape of postpedal segments; etc. In his description Chamberlin states " First joint of telopodite of first maxillae bearing a sensory lappet, the syncoxite with none ", but the coxosternite of the first maxillae actually bears lappets (Figs. 99 – 101: a). About the ventral pores, the author says " Ventral pores present in a circular area in front of caudal margin of sternite ", this is correct for the metasternites of the anterior region of the body, but in those of the posterior region, the pore-fields are divided in two subsymmetrical areas.

Remarks. Chamberlin (1955) stated that the syntypical series comprised three specimens (all with 49 legbearing segments), but actually comprises two (apparently one of these is now missing); the author gives 28 mm as body length for the species, because the trunk of the lectotype is incomplete, it is not possible to determine if this length corresponds to it (or to the presumptive missing specimen of unknown sex). Lectotype male with forcipular segment and 15 leg-bearing segments of posterior region of the trunk, missing. Paralectotype female complete, showing ova and spermathecae without spermatozoa (located at level of leg-bearing segment 48). Depository of types. CAS.

Remarks. P. zapallar can be separated from the other South American members of Plateurytion using the identification key below.

Other material examined. CHILE: Region IV (Coquimbo region): Elqui province: 11 km N of Los Vilos, 11 November 1987, E. Maury coll.: 1 ♀ with 47 l. - b. s., b. l. 26 mm (MACN-My 25). Region V (Valparaíso region). Petorca province: Quebrada Huaquén, Pichicuy, 7 January 1984, E. Maury coll.: 1 ♂ with 47 l. - b. s., b. l. 22 mm (MACN-My 26). Quillota province: Parque Nacional La Campana, Palmas de Ocoa, 8 – 5 November 1987, E. Maury coll.: 1 ♀ with 53 l. - b. s., b. l. 28 mm (MACN-My 27); same locality and collector, 27 – 28 October 1988, 1 ♂ with 51 l. - b. s., b. l. 23 mm (MACN-My 28); same locality, 32 º 57´40.4 ´´ S, 71 º 03´34.0 ´´ W, 770 m a. s. l., 18 February, 2005, M. J. Ramírez & F. Labarque coll.: 1 ♂ with 51 l. - b. s., b. l. 25 mm (MACN-My 29). Valparaíso province: Quebrada el Tigre, Cachagua, 8 November 1988, E. Maury coll.: 1 ♂ with 47 l. - b. s., b. l. 27 mm (MACN-My 30).

Type locality. CHILE: Aconcagua: Zapallar. (According to the current Chilean territorial organization, Zapallar belongs to Petorca province). Known range. CHILE: Region IV (Coquimbo region): Elqui province: 11 Km N of Los Vilos. Region V (Valparaíso region). Petorca province: Zapallar; Quebrada Huaquén, Pichicuy. Quilota province: La Campana National Park. Valparaíso province: Quebrada el Tigre, Cachagua. (See Fig. 110).

Type material examined. CHILE: Aconcagua: Zapallar, 27 November, 1950 (collector?), two syntypes here designated as lectotype ♂ with 49 l. - b. s., (b. l. 28 mm?) (head capsule with mandibles, dissected first and second maxillae, leg-bearing segments 42 - 49 and postpedal segments, in an original permanent slide; 26 l. - b. s. of anterior region of the body, in two parts of 5 and 21 each, in alcohol); paralectotype ♀, subadult, with 49 l. - b. s., b. l. 17 mm (undissected, in alcohol). Both specimens labeled as Chilerium zapallar Chamberlin (CAS Entomology type Nº 9174).