Limnesia (Limnesia)

Smit, H., 2011, New Species Of Water Mites From New Guinea (Acari: Hydrachnidia, Halacaridae), Acarologia 51 (3), pp. 321-345 : 328-331

Limnesia (Limnesia) baderi ( Imamura, 1983)

Material examined — 2/1/0, River Pos 7, Sentani, 2°33.740’ S; 140°30.784’ E, alt. 103 m a.s.l., 9- iii-2010 ; 1/1/0, River Yabawi , upstream of Harapan, 2°34.216’ S; 140°33.723’ E, alt. 120 m a.s.l., 28- iii-2010 ; 5/2/0, River Kamp Walker , near UNCEN, Abepura, 2°34.202’ S; 140°38.886’ E, alt. 144 m a.s.l., 31-iii-2010 .

Remarks — A hyporheic species ( Imamura 1983), found in gravel deposits of streams. Thus far only reported from Papua New Guinea.

Limnesia (Limnesia) longiseta n. sp. ( Figure 3 )

Material examined — Holotype male, Bion River, upstream, Pass Valley, Papua province, New Guinea, Indonesia, 3°51.513’ S; 139°05.570’ E, alt. 2007 m a.s.l., 15-iii-2010. Paratype: one female, same data as holotype .

Diagnosis — Dorsal setae very long; acetabula elongated, lying in an arc in the male.

Description — Male: Idiosoma dorsally 530 long and 328 wide, pear-shaped, colourless to paleyellow. Dorsum with two large plates, anterior plate 188 long and 244 wide, posterior plate 296 long and 284 wide, each plate with two pairs of setae. Posterior plate with two pairs of very long setae, anterior plate with only posterior pair very long ( Figure 3b ). Suture lines of coxae indistinct. Posterior part of ventrum sclerotized. Glandula Limnesiae in the middle of third coxae, associated setae posterior of these glandularia ( Figure 3a ). Genital field fused with ventrum, with three pairs of acetabula lying in an arc; gonopore 52 long. Acetabula elongated, anterior acetabulum 40 long and 16 wide. Lengths of PI-PV: 15, 70, 44, 72, 30. Ventral margin of PII with an anteriorly placed stout seta, ventral margin of PIV with two short setae and one long seta on a small tubercle ( Figure 3c ). Lengths of I-leg-4-6: 72, 88, 64. Lengths of IV-leg-4-6: 84, 102, 76; IV-leg-6 with a distal setae, 58 long. Claws of first, second and third legs large with a small clawlet, without claw blade. Legs without swimming setae.

Female: Idiosoma dorsally 583 long and 354 wide, ventrally 648 long. Dorsum with two large plates, anterior plate 218 long and 258 wide, posterior plate 340 long and 308 wide. Anterior plate with three pairs of setae, middle pair enlarged. Posterior plate with two pairs of enlarged setae. Female in many aspects similar to male, only differing in size and genital field. Genital field with three pairs of acetabula lying on the genital flaps ( Figure 3d ). Acetabula elongated, anterior acetabulum 42 long and 18 wide. Lengths of PI-PV: 18, 70, 60, 82, 38; palp as in male. Lengths of I-leg-4-6: 82, 92, 80. Lengths of IV-leg-4-6: 80, 96, 100; IV-leg-6 with a distal seta 42 long. Legs as in male.

Etymology — Named for the long dorsal setae.

Remarks — The new species is close to Limnesia baderi, but differs in size (the male of L. baderi is dorsally 429 long), the long setae (short in L. baderi) and the acetabula are elongated (rounded in L. baderi) and are lying in an arc (behind each other).

Limnesia (Limnesia) papuensis n. sp. ( Figure 4 )

Material examined — Holotype male, unnamed creek, UNCEN forest, Abepura , Papua province, New Guinea, Indonesia, 2°34.925’ S; 140°39.173’ E, alt. 177 m a.s.l., 31-iii-2010 . Paratypes: 8/4/0, same data as holotype; 2/3/0, unnamed creek UNCEN forest, Abepura , Papua province, New Guinea, Indonesia, 2°34.794’ S; 140°39.292’ E, alt. 234 m a.s.l., 31-iii-2010 .

Diagnosis — First coxae fused, ventral margin of PII with a long seta on a small tubercle, posterior ventral seta of PIV on a small tubercle, IV-leg-6 without distal seta.

Description — Male: Idiosoma lineated, 624 (470 – 672) long and 526 (377 – 502) wide. Dorsally with a posterior, slightly rectangular to rounded platelet ( Figure 4b ), 80 (55 – 74) long and 68 (70 – 82) wide. Idiosoma colour yellowish, coxae light reddish. Gnathosomal bay V-shaped. First coxae fused medially. Anterior coxae with short apodemes, third coxae with short secondary sclerotization. Glandula Limnesiae located on third coxae, associated setae close to Glandula Limnesiae ( Figure 4a ). Genital field 144 long and 136 wide with three pairs of acetabula. Genital flaps bean-shaped; pre- and postgenital sclerite small, the latter largest. Lengths of PI-PV: 16, 51, 71, 112, 32. Ventral margin of PII with an anteriorly directed seta on a very small tubercle; most anterior seta of ventral margin of PIV on a small tubercle ( Figure 4c ). Lengths of I-leg-4-6: 88, 98, 92. Lengths of IV-leg-4-6: 130, 136, 142; IV-leg- 6 without a distal seta. First, second and third legs with a claw with clawlet and without claw blade. Third and fourth legs with numerous swimming setae. Excretory pore smooth.

Female: Idiosoma lineated, 656 (535 – 770) long and 498 (462 – 599) wide. Dorsally with a posterior, slightly rectangular to rounded platelet, 71 (64 – 72) long and 74 (70 – 74) wide. Coxal field as in male. Genital field pear-shaped with three pairs of acetabula ( Figure 4d ), 174 long and 116 wide. Lengths of PI-PV: 22, 74, 70, 114, 32; palp as in male. Lengths of I-leg-4-6: 88, 94, 92. Lengths of IV-leg-4-6: 134, 130, 142; IV-leg-6 without distal seta. Legs as in male. Excretory pore smooth.

Etymology — Named for its occurrence in

Papua province.

Remarks — The new species is close to L. buruensis Viets, 1923 and L. argelooi Smit, 1996 , but differs in having the first coxae fused medially (lying close to each other but not fused in L. buruensis and L. argelooi ), the Glandula Limnesiae are located in the middle of the third coxae (similar in L. argelooi but in posteromedial corner in L. buruensis). Moreover, PIV of L. buruensis is more slender, while both L. argelooi and L. buruensis lack the small setal tubercle of PIV.

Limnesia (Limnesia) pseudopatens n. sp. ( Figure 5 )

Material examined — Holotype male, brown forest pool, along road Yoka – outlet Lake Sentani, Papua province, New Guinea, Indonesia, 2°40.737’ S; 140°36.230’ E, alt. 104 m a.s.l., 29-iii-2010. Paratypes: 3/4/4, same data as holotype .

Diagnosis — Ventral margin of PII with a broad, posteriorly directed stout seta, which is contracted at its tip.

Description — Male: Idiosoma 1327 (1166 – 1286) long and 1025 (1075 – 1166) wide, colour of chitinous parts and legs lilac. Dorsal platelets absent. First coxal plates not fused medially. Glandula Limnesiae lying in an indentation between third and fourth coxal plates, associated setae in the middle of third coxal plates, near medial margin. Anterior coxal plates with short apodemes, third coxal plates medially with secondary sclerotization ( Figure 5a ). Genital field bean-shaped, with three pairs of acetabula, acetabula large and occupying most area of genital field ( Figure 5b ). Genital field 186 long and 211 wide. Pre-genital sclerite short, postgenital sclerite more elongate. Lengths of PI-PV: 18, 72, 80, 90, 44. Ventral margin of PII straight, with a broad, distally contracted seta, this seta directed posteriorly. PIV anteriorly with four setae near ventral margin, PV narrow ( Figure 5c ). I-leg-4-6: 122, 154, 138. Lengths of IV-leg-4-6: 219, 206, 178; IV-leg- 6 with a long, distal seta (88 long, pinnate at tip) and four shorter pinnate setae. Third and fourth legs with numerous swimming setae. Excretory pore not sclerotized.

Female: Idiosoma soft, 1286 (1206 – 1668) long and 1029 (965 – 1407) wide, colour of chitinous parts and legs lilac. Dorsal platelets absent. First coxal plates not fused medially. Glandula Limnesiae lying in an indentation between third and fourth coxal plates, associated setae in the middle of third coxal plates, near medial margin. Anterior coxal plates with short apodemes, third coxal plates medially with secondary sclerotization ( Figure 5d ). Genital field with three pairs of acetabula, acetabula large and occupying most area of genital field ( Figure 5e ). Prae- and post-genital sclerites long and narrow. Lengths of PI-PV: 14, 72, 87, 94, 42. Ventral margin of PII straight, with a broad, distally contracted seta, this seta directed posteriorly. PIV with two setae, and more anteriorly two small setae lying close to each other, PV narrow. Lengths of I-leg- 4-6: 126, 162, 122. Lengths of IV-leg-4-6: 259, 239, 202; IV-leg-6 with a distal seta, 101 long. Third and fourth legs with numerous swimming setae. Excretory pore not sclerotized.

Deutonymph: Idiosoma 595 – 868 long and 486 – 656 wide. As adult, with provisional genital field with two fused pairs of acetabula. Ventral margin of PII without seta.

Etymology — Named for its similarity with Limnesia patens Viets, 1935.

Remarks — The new species is very close to Limnesia patens from Java (Viets 1935) and India ( Cook 1967), and differs only in the shape of the palp. The stout seta of the ventral margin of PII is broad and contracted distally in the new species, while in L. patens it is not contracted. Moreover, the longest dorsal setae of PII is longer in L. patens (length 56 in female, 42 in L. pseudopatens ), while PIV is much stronger bowed in L. patens. Another very similar species is Limnesia szalayi Viets, 1955 from northern Australia. The latter species has a dorsal platelet, while PIV is more narrowed distally.

Figures

FIGURE 3: Limnesia longiseta n. sp., holotype male: a – ventral view; b – dorsal view; b – palp; c – genital field. Scale bar = 50 µm.

FIGURE 4: Limnesia papuensis n. sp., holotype male: a – ventral view; b – dorsal view; c – palp; d – ventral view. Scale bar = 50 µm.

FIGURE 5: Limnesia pseudopatens n. sp.. Holotype male: a – ventral view (Scale bar = 200 µm); b – genital field (Scale bar = 50 µm); c – palp (Scale bar = 50 µm). Paratype female: d – ventral view (Scale bar = 200 µm); e – genital field (Scale bar = 50 µm).