Halacarus omului Pepato & Silveira, 2013, sp. nov.

Halacarus omului sp. nov.

(Figs 1–2)

Holotype: Female (UFMG-AC1200163), on Sargassum cymosum C. Agardh, 1820 at Lázaro Beach, Ubatuba, July 1991, coll. R. Curvelo.

Paratypes: Seventeen females (UFMG-AC1200088–1200096, 1200110–1200116, 1200155), on algae at Massaguaçu Island, Caraguatatuba, 27 September 2001, coll. BIOTA /FAPESP; six females (UFMG 1200144– 1200147, 1200153–1200154), on algae at Massaguaçu Island, Caraguatatuba, 28 September 2001, coll. BIOTA / FAPESP; three females (UFMG-AC1200136–1200138) on algae at Massaguaçu Island, Caraguatatuba, 16 March 2001, coll. BIOTA /FAPESP; two females (UFMG-AC1200162, 1200166), on Sargassum cymosum C. Agardh, 1820 at Lázaro Beach, Ubatuba, July 1991, coll. R. Curvelo; seventeen males (UFMG-AC1200097–1200103, 1200117– 1200126), on algae at Massaguaçu Island, Caraguatatuba, 27 September 2001, coll. BIOTA /FAPESP; six males (UFMG-AC1200130–1200135), on algae at Massaguaçu Island, Caraguatatuba, 16 March 2001, coll. BIOTA / FAPESP; nine males (UFMG-AC1200152, 1200160–1200161, 1200168, 1200170–1200171, 1200173–1200175), on Sargassum cymosum C. Agardh, 1820 at Lázaro Beach, Ubatuba, July 1991, coll. R. Curvelo; quiescent male (UFMG-AC1200109), on algae at Massaguaçu Island, Caraguatatuba, 27 September 2001, coll. BIOTA /FAPESP; eight deutonymphs (UFMG-AC1200104–1200108, 1200127–1200129), on algae at Massaguaçu Island, Caraguatatuba, 27 September 2001, coll. BIOTA /FAPESP; three deutonymphs (UFMG-AC1200143, 1200149– 1200150), on algae at Massaguaçu Island, Caraguatatuba, 16 March 2001, coll. BIOTA /FAPESP; four deutonymphs (UFMG-AC 1200151, 1200159, 1200167, 1200172), on Sargassum cymosum C. Agardh, 1820 at Lázaro Beach, Ubatuba, July 1991, coll. R. Curvelo; deutonymph (UFMG-AC1200148), on algae at Massaguaçu Island, Caraguatatuba, 28 September 2001, coll. BIOTA /FAPESP; quiescent deutonymph (UFMG-AC1200139), on algae at Massaguaçu Island, Caraguatatuba, 16 March 2001, coll. BIOTA /FAPESP; three protonymphs (UFMG-AC1200140– 1200142), on algae at Massaguaçu Island, Caraguatatuba, 16 March 2001, coll. BIOTA /FAPESP.

Description. Female: Idiosoma length 475–538, 55–65 μm long anterior spine included, width 260–330. AD length 175–188, width 70–83, almost indiscernible, only discriminated from remaining idiosoma by its slightly reticulate ornamentation instead of faint maze-like marks or striations in the surrounding area. Anterior spine 0.27– 0.41 of AD length. Ds-1 on AD, anterior to gp-1. Gp-1 at level of 0.55–0.62 of AD.

OC lacking, except for smooth corneae (Fig. 1 B). Ds-2 on membranous cuticle between AD and corneae. Gp- 2 placed laterally, at level of 0.32–0.38 of idiosoma. Pore canaliculi on striated cuticle, near lateral eyes. Gp-3 at level of 0.40–0.45 of idiosoma. PD absent, tegument of posterior idiosoma maze-like, as shown in Fig. 1 D. Insertions of ds-5 and adanal setae adjacent to gp-4 and gp-5 (Fig. 1 C), respectively. Ds-5 at level of 0.69–0.74 of idiosoma.

AE length 65–80, width 245–280, with three pairs of setae and without epimeral pores. PE with three ventral setae and one dorsal seta.

One pair of pgs placed on membranous cuticle, at 28–58 μm or at 0.66–1.19 relative to the distance between the anterior margins of GA and GO from anterior edge of GA. GA length 90–113, width 125–148. GO length 43– 53, width 35–48, at 43–58 μm from anterior edge of GA. Two pairs of pgs on genitoanal plate, close to GO. Five pairs of sgs on genital sclerites, grouped 2:3. Epicuticle raised on GA, appearing as refrigent area indicated by a dotted line in Fig. 1 D.

Gnathosoma length 153–172, width 75–88. Rostrum length 92–105, equal to 0.58–0.63 of gnathosoma length. Trito- and basirostral setae on rostrum, two small cuticular processes at its tip (Fig. 1 F).

Legs with integument faintly reticulated or without conspicuous ornamentation. Leg chaetotaxy as follows: Leg I, 1, 2, 10 (2S), 10 (2S), 13 (4S), 5 (2S); leg II, 1, 4, 8, 10 (1S, 1B), 12 (2S, 2B),7; leg III, 2, 2, 7, 7, 9, 8; leg IV, 1, 2, 5, 6, 9, 7. Tarsus I with three dorsal and two ventral setae, three pairs of eupathidia as parambulacral setae, and setiform famulus and solenidion. Tarsus II with three dorsal and four ventral setae, three pairs of eupathidia and a setiform solenidion. Tarsi III-IV with two pairs of ventral setae and a pair of parambulacral setae. Tarsi III and IV with four and three dorsal setae, respectively (Fig. 1 K, H). Length of telofemora, genua and tibiae of leg I, 143–160 μm, 130–143 μm, and 120–133 μm, respectively.

Lateral claws not pectinate, with a narrow accessory process. Median claw bidentate (Fig. 1 I–M).

Male: Idiosoma length 430–470, width 260–330. Similar to female in most features except for those in the genital area and the plumose parambulacral setae on tarsus IV.

GA length 91–111, width 119–138. A pair of pgs on membranous cuticle at 12–24 μm from the anterior edge of GA. Genital opening length 42–47, width 33–41, at 33–40 μm from the anterior margin of GA. 58–82 perigenital setae surrounding GO, beside a pair of distinctly stouter and longer (outlying) setae. Five pairs of sgs on genital sclerites, grouped 2:3. Spermatophorotype extending 17–24 μm beyond genital opening (Fig. 1 G).

Deutonymph: Idiosoma length 320–425. Integument of posterior dorsal portion of idiosoma striated instead of maze-like, as found in adults. Two pairs of pgs on striated cuticle near genital plate. A pair of shorter setae on plate close to primordial GO. Underneath the genital plate, two pairs of genital acetabula found (Fig. 2 B). Leg chaetotaxy: Leg I, 1, 2, 8 (2S),8 (2S), 11 (4S), 5 (2S); leg II, 1, 4, 6, 8 (1S), 10 (2S, 1B),7; leg III, 2, 2, 5, 6, 8, 6; leg IV, 1, 2, 3, 4, 7–8, 5. Ventral setae on tarsi I-IV: 2, 4, 2, 2.

Protonymph: Idiosoma length 213–320. Similar to deutonymphs regarding dorsal aspects of idiosoma. PE with two ventral setae and one dorsal seta. A single pair of pgs close to primordial GO. Underneath genital sclerite, a single pair of genital acetabula found (Figs. 2 H).

Leg chaetotaxy: Leg I, 1, 2, 6 (2S), 6 (2S), 9 (4S), 5 (2S); leg II, 1, 3, 5, 6 (1S), 6 (1B), 5; leg III, 2, 2, 3, 3, 5–6, 5; leg IV, 0, 3, 3, 5, 3. Ventral setae on tarsi I-IV: 2, 2, 1, 0.

Etymology. The specific name refers to Omulu, an African god that is a member of the Candomble and the Umbanda pantheons, who is syncretically taken in Umbanda as Saint Lazarus. Hence, the name refers indirectly to the type locality, Lázaro Beach. It refers also to the fact that both Saint Lazarus and Omulu are depicted with skin pustules in their representations, and Halacarus species have well-developed gland pores.

Remarks. Halacarus omului sp. nov. belongs to the actenos species group, defined by the lacking of PD in both sexes, reduction or absence of OC, long apodemes on AE and PE, GA with rather uniform cerotegumental cover and two pairs of pgs adjacent to GO in the female, one pair (rarely two pairs) of pgs anterior to GA, one or two bipectinate setae on tibia II, claw shaft without tines, lateral claws often with pectinate accessory process (Bartsch, 2011).

Currently, this group consists of 21 species: H. actenos Trouessart, 1889, H. griseus Bartsch, 1987, H. longiunguis Police, 1909, H. prolongatus Bartsch, 1996, and H. leptopus Bartsch, 2002 from the North Atlantic and the Mediterranean; H. spongiphilus Kishida, 1927, H. magniporus Krantz,1973, and H. mollis Sokolov, 1952 from the North Pacific; H. higginsi Newell, 1984, and H. perditus Newell, 1984 from the Southeastern Pacific; H. nitidus Bartsch, 1979, and H. socius Bartsch, 1992 from the Tropical Southern Pacific; H. discophorus, Bartsch, 1993, H. flavellus Bartsch, 1993, H. fuscatus Bartsch, 1993, and H. multispinus Bartsch, 1981 from the Indian Ocean; H. echinatus Newell, 1984, H. falklandensis Newell, 1984, H. hemispinosus Newell, 1984, H. robustus Lohmann, 1907, and H. werthi Lohmann, 1907 from the Antarctic, Subantarctic and the adjacent sea (Bartsch, 2002, 2011).

Among these species, only H. actenos, H. leptopus, H. griseus, H. magniporus, H. prolongatus, H. longiunguis and H. discophorus share the presence of ds-5 and gp-4, and adanal setae and gp-5, adjacent on the same sclerites with H. omului sp. nov. (Bartsch, 2011).

idiosoma, length (in µm) frontal spine dorsum

Species female male size size in relation to shape of posterior position gp-1 on

length of AD AD AD

Some taxonomic characters listed by Bartsch (2011) are scored for Halacarus omului sp. nov. and the seven species mentioned above in Table 1. Halacarus actenos differs from the present new species in having two setae on trochanter IV instead of one, by the absence of outlying setae on GA in the male, and by the gp-1 placed on the lateral edge of AD (Bartsch, 1980). Halacarus leptopus is distinguishable form H. omului by the absence of ventromedial bipectinate setae on genu II as well as a single such seta on tibiae II (Bartsch, 2002). Halacarus discophorus differs from H. omului by having a pair of sclerites among gp-4 and gp- 5 in the male, the triangular outline of posterior margin of AD, oval OC with the cornea, and four pairs of outlying pgs on GA in the male instead of a single pair of such setae (Bartsch, 1993). Halacarus longiunguis differs from H. omului in the lack of corneae, the presence of the accessory process on the lateral claws of tarsi III-IV, and only three ventral setae on tarsi IV (Bartsch, 2007). Halacarus magniporus is discriminated from H. omului by the protruded posterior margin of AD and the strong boat-shaped spine on P3 (Krantz, 1973). Halacarus prolongatus differs from the present new species in the convex posterior margin of AD and the absence of OC and corneae in the ocular area (Bartsch, 1996).

Newell (1947) assigned H. actenos to Florida, USA, based on the study of a male, a female and three deutonymphs. Except for the deutonymph, all of the specimens had lost their distal leg segments before Newell’s examination. Halacaridae species are known to be shared by Caribbean Sea and Brazilian coastline (e.g. Copidognathus floridensis (Newell, 1947), C. modestus Bartsch, 1984 and C. longispinus Bartsch & Iliffe, 1985 – Pepato & Tiago, 2005). Nevertheless, similar to other H. actenos specimens, Newell’s material has the trochanter chaetotaxy of 1, 1, 2, 2 (Bartsch, 2011), whereas the species described here has a 1, 1, 2, 1 trochanter formula.