Pectiniunguis aequatorialis, Pereira, 2018

Pereira, Luis Alberto, 2018, A new high-altitude species of centipede from the Andes of Ecuador (Chilopoda, Geophilomorpha, Schendylidae), Zootaxa 4374 (3), pp. 409-426 : 410-421

publication ID	https://doi.org/ 10.11646/zootaxa.4374.3.5
publication LSID	lsid:zoobank.org:pub:3C124A87-F38F-455E-B3B7-463845B28D3E
DOI	https://doi.org/10.5281/zenodo.5955529
persistent identifier	https://treatment.plazi.org/id/03DF137A-FFA7-9271-FF2C-DD1C5FF8FE54
treatment provided by	Plazi
scientific name	Pectiniunguis aequatorialis
status	sp. nov.

Treatment

Pectiniunguis aequatorialis sp. nov.

( Figs 1–56 View FIGURES 1–7 View FIGURES 8–17 View FIGURES 18–24 View FIGURES25–32 View FIGURES 33–40 View FIGURES 41–47 View FIGURES 48–53 View FIGURES 54–56 , 69 View FIGURE 69 , 70 View FIGURE 70 )

Diagnosis. A Neotropical member of Pectiniunguis with ventral pore-fields on the anterior region of the body only (absent on first metasternite). (Of the other New World species currently included in the genus, only P. aequatorialis and P. ascendens Pereira, Minelli & Barbieri, 1994 , from Brazil share this character.) Pectiniunguis aequatorialis is differentiated from P. ascendens by the following traits: body length of male 19 mm (33 mm, female); trunk with subepithelial pigmentation present, Fig 54 View FIGURES 54–56 (absent in P. ascendens ); a.a. XIV with clavate sensilla on the external edge only, Figs. 2, 3 View FIGURES 1–7 (on the external and internal edges in P. ascendens ); a.a. II-XIII nearly as long as wide, Fig. 1 View FIGURES 1–7 (longer than wide, in P. ascendens , Figs. 57, 58 View FIGURES 57–68 ); dentate lamellae of mandibles divided in two blocks, Figs. 14–17 View FIGURES 8–17 (in three blocks in P. ascendens ); length/width ratio of forcipular trochanteroprefemur ca. 1.08: 1 (ca. 1.30: 1 in P. ascendens ); internal edge of forcipular ungulum very slightly crenulated, Figs. 22–24 View FIGURES 18–24 (completely smooth, in P. ascendens , Fig. 60 View FIGURES 57–68 ); ultimate leg-bearing segment with intercalary pleurites at the sides of the ultimate pretergite, Fig. 47 View FIGURES 41–47 : b (without intercalary pleurites, in P. ascendens , Fig. 66 View FIGURES 57–68 ); pretarsus of ultimate legs absent (present, in P. ascendens , Fig. 68 View FIGURES 57–68 ). Other morphological traits that differentiate P. aequatorialis from P. ascendens are listed in Table 1.

P. aequatorialis P. ascendens Body length 19 mm (♂) 33 mm (♀) Color (of preserved specimen in ethanol) bright ferrugineous yellow, forcipular segment darker (pale

ocherous) Trunk sub-epithelial pigmentation present on leg-bearing segments 1 to absent penultimate ( Fig. 54 View FIGURES 54–56 )

Cephalic plate nearly as long as wide slightly longer than wide, ratio ca. 1.2: 1 Clavate sensilla of a.a. XIV present on the external edge only (Figs. present on the external and internal

2, 3) edges A.a. II-XIII nearly as long as wide ( Fig. 1 View FIGURES 1–7 ) longer than wide ( Figs. 57, 58 View FIGURES 57–68 ) Ratio width of a.a. II/width of a.a. XIV ca. 1.15: 1 ca. 1.35: 1 Length/width ratio of a.a. XIV ca. 1.60: 1 ca. 2.00: 1 Clypeal median setae distributed on the central area ( Fig. 12 View FIGURES 8–17 ) distributed on the central and lateral

areas ( Fig. 59 View FIGURES 57–68 ) Number of blocks of dentate lamellae of two ( Figs. 14–17 View FIGURES 8–17 ) three mandibles

Length/width ratio of forcipular ca. 1.08: 1 ca. 1.30: 1 trochanteroprefemur

Ventral internal edge of forcipular very slightly crenulated ( Figs. 22–24 View FIGURES 18–24 ) completely smooth ( Fig. 60 View FIGURES 57–68 ) ungulum

Shape of sternal pore-fields as in Fig. 26 View FIGURES25–32 (on metasternite 3); Fig. 27 View FIGURES25–32 as in Fig. 61 View FIGURES 57–68 (on metasternite 3); Fig. 62 View FIGURES 57–68

(4); Fig. 28 View FIGURES25–32 (7); Fig. 31 View FIGURES25–32 (12) (4); Fig. 63 View FIGURES 57–68 (8); Fig. 64 View FIGURES 57–68 (12) Ultimate leg-bearing segment with yes ( Fig. 47 View FIGURES 41–47 : b) no ( Fig. 66 View FIGURES 57–68 ) intercalary pleurites at the sides of the

ultimate pretergite

Length/width ratio of metasternite of ca. 0.58: 1 ca. 0.75: 1 male ultimate leg-bearing segment

Shape and pilosity of male ultimate legs as in Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 as in Figs. 66, 67 View FIGURES 57–68 Pretarsus of ultimate legs absent as a diminutive tubercle with two small

apical spines ( Fig. 68 View FIGURES 57–68 ) Relative size of anterior coxal organs as in Fig. 49 View FIGURES 48–53 as in Fig. 65 View FIGURES 57–68

Remarks. Aside from the similarities between P. aequatorialis and P. ascendens mentioned in the diagnosis above, the new species shares with P. gaigei (Chamberlin, 1921) (from Guyana); P. roigi Pereira, Foddai & Minelli, 2001 (from Ecuador); P. ducalis Pereira, Minelli & Barbieri, 1995 (from Brazil); and P. geayi (Brölemann & Ribaut, 1911) (from Brazil) the following characters: ventral pore-field absent on the first metasternite; all porefields undivided; accessory spines of walking legs thin and pale. Pectiniunguis aequatorialis can be confidently differentiated from the latter, by having pore-fields on the anterior region of the body only (vis-à-vis present along all the body length in the four aforementioned taxa).

Type material examined. Ecuador: Napo province: Cayambe-Coca Ecological Reserve, road to Papallacta, Oyacachi S00°16´20.0´´ W078°05´37.2´´, elevation 3823 m a.s.l. (error 8 m) GPS, 1 December 2009, Colls: M. Izquierdo, N. Platnick, N. Dupérré, A. Bonaldo & E. Tapia (PBI expedition), Paramo landscape (in leaf litter): holotype male with 45 leg-bearing segments, body length 19 mm, in ethanol, head detached from trunk ( QCAZ).

(The adult condition of the male holotype is confirmed by the presence of mature spermatozoa in the tubula seminifera, Fig. 53 View FIGURES 48–53 .)

Other material examined. Same locality, date, and collectors as the holotype: 1 male juvenile with 45 legbearing segments, body length 12 mm (MACN-My 51).

Description. Male holotype (adult). General features. Forty-five leg-bearing segments, body length 19 mm, maximum body width 1.30 mm, maximum cephalic plate width 0.76 mm, maximum cephalic plate length 0.77 mm, maximum forcipular coxosternite width 1.00 mm. Colour (preserved specimen in ethanol): bright ferrugineous, leg-bearing segments 1 to penultimate (44) with subepithelial pigmentation (nephrocytes?) distributed as in Fig. 54 View FIGURES 54–56 . Antennae. 2.8 times longer than the cephalic plate, distally slightly attenuate; ratio of width of a.a. II/width of a.a. XIV ca. 1.15: 1; a.a. I wider than long; a.a. II to XIII all nearly as long as wide; a.a. XIV longer than wide with length/width ratio ca. 1.60: 1. Ventral chaetotaxy: setae on a.a. I to IV-V of various lengths and relatively few in number; those on a.a. VI-XIV progressively shorter and more numerous towards the tip of the appendage ( Fig. 1 View FIGURES 1–7 ). Dorsal chaetotaxy: setae on a.a. I to IV-V similar to the ventral side, setae on remaining a.a. slightly longer and less numerous. Apical a.a. with ca. 19 clavate sensilla on the external border, absent on the internal border ( Figs. 2, 3 View FIGURES 1–7 ); distal end with ca. 6 specialized sensilla not split apically ( Fig. 2, 3 View FIGURES 1–7 ). Ventral and dorsal surface of a.a. II ( Figs. 4, 7 View FIGURES 1–7 ), V ( Figs. 5 View FIGURES 1–7 , 8 View FIGURES 8–17 ), IX ( Figs. 6 View FIGURES 1–7 , 9 View FIGURES 8–17 ) and XIII ( Figs. 2 View FIGURES 1–7 , 10 View FIGURES 8–17 ) with very small specialized sensilla; on the ventral side the sensilla are situated on the internal latero-apical area and are represented by two different types (a and b). Type a sensilla very thin and not split apically ( Fig. 2 View FIGURES 1–7 : a), type b sensilla ( Fig. 2 View FIGURES 1–7 : b) very similar to those of the apex of a.a. XIV. Specialized sensilla on dorsal side restricted to a middle and external apical areas, represented by three different types: a and b similar to a and b of ventral side ( Fig. 10 View FIGURES 8–17 : a, b) and type c sensilla, similar to type b, but thicker, and darker (ocherous in color) ( Fig. 10 View FIGURES 8–17 : c). Relative position of specialized sensilla on ventral and dorsal surfaces of a.a. as in Figs. 2, 4–6 and 7–10 View FIGURES 1–7 View FIGURES 8–17 . Number, distribution of type a, b, and c sensilla as in Table 2. Cephalic plate. Nearly as long as wide. Anterior margin convex, posterior margin nearly straight, lateral margins convex, anterior and posterior sides curved. Shape and chaetotaxy as in Fig. 11 View FIGURES 8–17 . Clypeus. With 1 + 1 postantennal setae, 4 + 5 median setae and 1 prelabral seta ( Fig. 12 View FIGURES 8–17 ). Labrum. Mid-piece with 11 robust teeth ( Fig. 13 View FIGURES 8–17 ). Side pieces with 8 + 7 teeth of which the most lateral ones are very small, all with a very sharp medial extension ( Fig. 13 View FIGURES 8–17 ). Mandible. Dentate lamellae subdivided into two distinct blocks, with 3, 2 teeth in the left mandible ( Figs. 14, 15 View FIGURES 8–17 ) and 3, 3 in the right ( Figs. 16, 17 View FIGURES 8–17 ), pectinate lamella with ca. 16–19 hyaline teeth ( Fig. 16 View FIGURES 8–17 ). First maxillae. Coxosternite and telopodites with well developed lappets ( Fig. 18 View FIGURES 18–24 : a, b). Coxosternite with 1 median seta and 1 + 1 setae at each side; coxal projections subtriangular, tip rounded and with 3 + 3 setae ( Fig. 19 View FIGURES 18–24 ). Article 2 of telopodites with 3 + 3 ventral setae ( Fig. 19 View FIGURES 18–24 ) and 4 + 5 dorsal sensilla ( Fig. 18 View FIGURES 18–24 ). Second maxillae. Coxosternite with 9 + 9 setae, arrangement and relative size as in Fig. 19 View FIGURES 18–24 . Pleurite joined to the posterior external region of the coxosternite through a non-reticulated area ( Fig. 20 View FIGURES 18–24 ). Apical claw of telopodites well developed, bipectinate, dorsal and ventral edges with ca. 11 teeth ( Fig. 21 View FIGURES 18–24 ). Forcipular segment. When closed, telopodites do not reach the anterior margin of the head. Forcipular tergite trapeziform, with anterior margin straight to very slightly concave, lateral margins slightly convex converging anteriad ( Fig. 23 View FIGURES 18–24 ); chaetotaxy: with an irregular transverse median band of ca. 12 setae and very few additional smaller setae distributed near the anterior and posterior margins, the latter covered by the tergite of the first leg-bearing segment ( Fig. 23 View FIGURES 18–24 ). Forcipular telopodites with articles unarmed ( Figs. 22–24 View FIGURES 18–24 ). Ventral internal edge of forcipular ungulum slightly crenulated ( Figs. 22–24 View FIGURES 18–24 ). Ratio between maximum length and maximum width of forcipular trochanteroprefemur ca. 1.08: 1. Calyx of poison gland cylindrical ( Fig. 24 View FIGURES 18–24 : b). Shape and chaetotaxy of forcipular coxosternite and telopodites as in Figs. 22, 23 View FIGURES 18–24 . Metasternites of leg-bearing segments 1 to penultimate. Pore-fields present from metasternite 2 to 19 (wholly absent on the remaining metasternites). All fields undivided, shape and relative size variable along the trunk as in Figs. 25–37 View FIGURES25–32 View FIGURES 33–40 . Number of pores on metasternites as follows: metasternite 2 (9 pores); 3 (20); 4 (30); 7 (34); 10 (39); 11 (38); 12 (45); 13 (54); 14 (42); 16 (36); 17 (38); 18 (20); 19 (12). Legs (pair 1 to penultimate). Chaetotaxy similar throughout the entire body length. Distribution, number and relative size of setae as in Figs. 38–43 View FIGURES 33–40 View FIGURES 41–47 . Claws ventrobasally with three thin and pale accessory spines, one anterior ( Figs. 44–46 View FIGURES 41–47 : a) and two posterior ( Figs. 45, 46 View FIGURES 41–47 : b). Ultimate leg-bearing segment. Intercalary pleurites present on both sides of the ultimate pretergite ( Fig. 47 View FIGURES 41–47 : b); ultimate presternite not divided medially ( Fig. 48 View FIGURES 48–53 ). Ratio of length to width of metatergite, 0.67: 1; ratio of length to width of metasternite, 0.58: 1. Shape and chaetotaxy of metatergite and metasternite as in Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 . Coxopleura slightly protuberant at distal-internal ventral ends, setae small and numerous on the distal-internal ventral area, remaining surface with few larger setae ( Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 ). Coxopleuron with two compound (‘heterogeneous’) coxal organs ( Figs. 48, 49 View FIGURES 48–53 ). Coxal organs open on the membrane between coxopleuron and metasternite, partially covered by the latter ( Figs. 48, 49 View FIGURES 48–53 ). Outer lobes of coxal organs with 1–3 individualized areas of mucosal layer ( Fig. 49 View FIGURES 48–53 : a). Ultimate legs ( Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 ) inflated, telopodites with six articles. Ratio of length of telopodites (of ultimate legs) to length of metasternite ca. 4.80: 1. Shape and chaetotaxy of ultimate legs as in Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 . Ultimate pretarsus absent ( Figs. 47 View FIGURES 41–47 , 48 View FIGURES 48–53 ). Postpedal segments. Intermediate tergite with posterior margin strongly convex ( Fig. 47 View FIGURES 41–47 ). Intermediate sternite with posterior margin concave. First genital sternite with posterior margin medially slightly convex, laterally slightly concave ( Figs. 48, 50 View FIGURES 48–53 ). Gonopods biarticulate ( Fig. 50 View FIGURES 48–53 : a), basal article with ca. 10 setae, apical article with ca. 5 setae ( Figs. 48, 51 View FIGURES 48–53 ). Penis with 1 + 1 apical setae on dorsal side ( Fig. 52 View FIGURES 48–53 ).

Post-embryonic variation of coxal organs and gonopods. An immature male (MACN-My 51), exhibits 1 + 1 anterior homogeneous coxal organs (“homogeneous coxal glands” sensu Brölemann & Ribaut 1912), and 1 + 1 posterior heterogeneous coxal organs ( Fig. 55 View FIGURES 54–56 ), both of which are incompletely developed due to the immature state of the specimen. In contrast, the mature holotype has 2 + 2 heterogeneous and completely developed coxal organs in the coxopleura of the ultimate leg-bearing segment ( Fig. 49 View FIGURES 48–53 ). Gonopods of immature male relatively smaller than those of the holotype, having only two setae on the basal article and one on the distal ( Fig. 56 View FIGURES 54–56 ); aspect of gonopods in the holotype as in Fig. 51 View FIGURES 48–53 .

Female. Unknown.

Etymology. The species is named after the geographic location of the type locality near the equator.

Ecology. The specimens were collected in leaf litter, at 3823 m. a.s.l., in a humid Paramo ecosystem (within the Paramo biogeographical province), in the Cayambe-Coca Ecological Reserve (High Andes of Ecuador). The Paramo biogeographical province (which belongs to the Amazon) occurs in the high cordilleras of Venezuela, Colombia, Ecuador and Peru, at elevations between ca. 3000 and 4500 m. For details regarding climate characteristics, altitudinal variation, vegetation types, and floristic and faunal components of this biogeographical province, see Cabrera & Willink (1973) and Morrone (2001, 2006, 2014, 2015).

Distribution. Known only from the type locality.