Willemia panamaensis, García-Gómez & Palacios-Vargas, 2019

García-Gómez, Arturo & Palacios-Vargas, José G., 2019, Description of a new species of Willemia (Collembola: Hypogastruridae) from Panama with key to Willemia species occurring in the Americas, Zootaxa 4674 (5), pp. 564-570 : 565-568

Willemia panamaensis sp. nov.

(Figs. 1–13)

Type locality: Panama, Barro Colorado Island . Holotype (♀), Distrito de La Chorrera: Barro Colorado Island; ex soil (9°05’02.6’’N, 79°39’48.2’’W) ; 14.iii.2017, 4.iv.2017, Y. Lopez et al. Coll. Paratypes (♀♀) and juveniles, with same data as holotype. All the material is deposited at LESM.

Type material: Holotype (♀) (Figs 1–13) body length 435 µm, paratypes (5 ♀♀, 2 juveniles), length (n=8) 408.3 µm, (range 324–510 µm).

Diagnosis: Ant. IV with four subcylindrical sensilla, one microsensillum v close to e2 and e3; PAO with nine vesicles; Tibiotarsi I–III with 12 setae; no tenent hairs; sensilla on Abd I–IV are in p4 position and p2 on Abd V; Abd. II–III with sensillum lanceolate.

Description: Colour whitish, tegumentary grainules fine and regularly distributed. Antenna (56.8 µ). Ant. I with 6 setae; Ant. II with 11 setae; Ant. III organ with two microsensilla (ms), and one guard sensillum (S) at each side, S.g.d. longer than S.g.v., sinuose and curved; S.g. v. short and straight; one additional microsensillum is present. Ant. IV with six sensilla: two globular (e3(S4), i2 (S7)), two internal ((i(S2), i1 (S9)), one dorsal (d(S8)) and one external (e2(S1)); apical vesicle simple (SO), one microsensillum close to d, and other microsensillum v close to e2 and e3 (Fig. 3). Postantennal organ (PAO) with nine vesicles (Fig. 2). Head lacking setae a 0 and c 1 (Fig1). Labrum with 2 setae. Labium with ABCD proximal setae, 4 basomedial (E, F, G and f) and 3 basolateral (c, d, e’) (Fig. 5). Dorsal chaetotaxy as in Figs 1, 4 and 9, most setae short and thin, increasing in length from anterior to posterior part of body; sensillary formula from Th. II to Abd. V as 022/ 111110; m 7 sensilla on thoracic segments cylindrical (Fig. 8) and p 4 lanceolate (Fig 7); Th. II with a microsensillum close to m 7 (Fig 6), Th. III lacking microsensillum (Fig. 4); sensilla on Abd. II–IV are in p 4 position (Fig. 9) and p2 on Abd. V (Fig. 9). Abd. I with cylindrical sensillum; Abd. II–III with sensillum lanceolate (Fig. 11), Abd. IV and V, lanceolate-cylindric (Fig. 12). Setae m 1, 2 and 3 lacking on Abd. IV (Fig. 9). Ventral chaetotaxy of abdomen as in Fig. 10.

Tibiotarsi I–III (Fig. 13) with 12 setae each, and two pretarsal, no tenent hairs, unguis without tooth; unguiculus absent. Ventral tube with 4+4 setae (Fig. 10), two small anal spines (Fig. 9), female genital plate with 3+3 pregenital setae, 3 circumgenital and 2 eugenital; male unknown. Anal valves with 10 setae each and 2 hr setae (Fig. 10).

Variation. One specimen has 8+8 vesicles in PAO, while all others have 9 + 9. Two paratypes are lacking seta m3 on Th. II and one specimen has 11 setae on Tita. III.

Etymology. The species is named after the country in which it was collected.

Remarks. Willemia panamaensis sp. nov. is close to W. brevispina Hüther, 1962 . The main differences are as follows. In the new species Ant. IV has four sensilla (d, e2, i and i1) and microsensillum v is close to e2 and e3, Ant. III organ has one ms at mid-region of the organ, and is not lateral as in W. brevispina ; abdominal setae and sensilla are twice as long on the distal segments of the new species than on W. brevispina . The two species share a similar number of vesicles in PAO. We list other differences in Table 1 .

Similar characters are: shape of apical vesicle on Ant. IV; two globular sensilla (e3(S4), i2 (S7)); c1 seta on head absent; 3+3 setae on thorax I; tibiotarsi I–III with 12 setae each; Abd. V with sensillum position at p2; a3 setae on abdominal sternite II absent; a3 seta on abdominal sternite IV present; m1 setae on abdominal sternite IV.

The new species was collected in tropical rainforest soil from Barro Colorado Island, Panamá, during the dry season. No males were collected. Five specimens were sequenced for the standard COI-5P marker (“DNA barcode”, Ratnasingham & Hebert 2013) at the Canadian Centre for DNA Barcoding. DNA was successfully recovered from two specimens, sequences BCICL047-19 (length 624bp) and BCICL048-19 (655bp), which were deposited in the project BCICL of the Barcode of Life Data System (http://www.barcodinglife.org/index.php).

Tables

TABLE 1. Main morphological differences between the Willemia buddenbrocki species group in the Americas.

Character	W. panamaensis	W. brevispina	W. buddenbrocki
Ant. IV subcylindrical sensilla	4	2	4
PAO vesicles	9	7–10	12–13
Tita I–III setae	12	12	11
Seta a3 on Abd. II	-	-	+
Unguiculus	-	+	?