Aspidiobates vanuaticus, Smit, Harry, 2004

Smit, Harry, 2004, Water mites from Pacific Islands (Acari: Hydrachnidia), Zootaxa 588, pp. 1-20 : 4-7

Aspidiobates vanuaticus n. sp.

( Figs. 2–10 )

Material examined

Holotype male, Wahrur River, Espiritu Santo, Vanuatu, 15º 17.748 S –167º 0 9.679 E, 14 m a.s.l., 31 October 2003. Paratypes: 36 males, 32 females, same data as holotype; 5 males, 2 females, 1 nymph, Buelapa River, Espiritu Santo, Vanuatu, 15º 34.718 S –167º 0 1.570 E, 30 October 2003; 2 females, Butmas stream, Espiritu Santo, Vanuatu, 15º 20.605 S –166º 58.553 E, 419 m a.s.l., 29 October 2003.

Other material: 27 males, 24 females, Kere River, Espiritu Santo, Vanuatu, 15º 34.226 S –166º 57.368 E, 9 m a.s.l., 30 October 2003.

Diagnosis

Dorsal shield with sexual dimorphism: both male and female with one large plate, and two smaller platelets in the male, and four smaller platelets in the female; PII without ventral projection; PIV without setal tubercles; I­leg­5 ventrodistally with a slightly bowed, truncated seta.

Description

Male: ventral and dorsal shields present. Ventral shield ( Fig. 2 ) 648 (551–640) long and 559 (504–591) wide. One specimen distinctly smaller, 510 long and 475 wide. Dorsal shield ( Fig. 4 ) with one large plate 551 long and 510 wide, and two posterior platelets, each 172 long and 50 wide. In one aberrant specimen these platelets 140 long and 28 wide. Large dorsal plate bearing three pairs of glandularia and the postocularia, the middle pair of glandularia lying much closer to each other than in the posterior and anterior pairs. Anchoral process of capitulum long. First coxal plates extending beyond anterior margin of central shield. Suture lines between coxal plates indistinct. Glandularium of fourth coxal plates extending beyond the suture line of third and fourth coxal plates. Genital field with three pairs of acetabula ( Fig. 3 ). Gonopore 68 long. Lengths of PI–PV: 17, 76, 77, 106, 32. PII without ventral projection ( Fig. 5 ), ventral margin of PIII somewhat irregularly shaped. Setal tubercles of PIV small. PII and PIII with a reticulate pattern. Lengths of I­leg­4­6: 152, 149, 101; I­leg­5 distally with a truncated, slightly bowed setae ( Fig. 6 ). Lengths of IV­leg­4­6 ( Fig. 7 ): 222, 225, 161. Claws of legs with clawlets, legs without swimming setae.

Female: ventral and dorsal shields present. Ventral shield ( Fig. 8 ) 769 (624–810) long and 668 (551–713) wide. Dorsal shield ( Fig. 10 ) with one large plate, 648 long and 591 wide, and two pairs of posterior platelets, the lateral pair 232–238 long and 81–82 wide, the middle pair 210–211 long and 77–80 wide. Large dorsal plate bearing two pairs of glandularia and the postocularia, the posterior pairs closer to each other than the anterior pair. Young, not fully sclerotised females with an undivided dorsal shield and distinct posteromedial apodemes of fourth coxal plates, reaching beyond coxoglandularia 2. In sclerotised females, these posteromedial apodemes are shorter and less distinct. Anchoral process of capitulum long. First coxal plates extending beyond anterior margin of central shield (but might appear shorter, depending on its position in the slide). Suture lines between coxal plates indistinct. Glandularium of fourth coxal plates extending beyond the suture line of third and fourth coxal plates. Genital field with three pairs of acetabula ( Fig. 9 ). Gonopore106 long and 112 wide. Lengths of PI–PV: 22, 98, 90, 128, 32; palp as in male. Lengths of I­leg­4­6: 171, 170, 112. Lengths of IV­leg­4­6: 248, 248, 168. Legs as in male.

Etymology

Named for its occurrence on Vanuatu.

Remarks

The new species belongs to a group of species in which the dorsal shield shows a sexual dimorphism: a large plate and two smaller platelets in the male, and a large plate with four smaller platelets in the female. To this group of species belong A. wittenoom Harvey and A. pilbara Harvey from Australia ( Harvey 1988), and A. serratus K.O. Viets , A. violaceus K.O. Viets , A. neocaledonicus Smit and A. suturalis Smit from New Caledonia ( K.O. Viets 1969, Smit 2002). The female of A. rarus Smit from New Caledonia has one large plate and four smaller platelets as well, but the male is unknown. From these species, A. wittenooom has for pairs of acetabula. From the remaining group with three pairs of acetabula, the new species differs from A. pilbara , A. serratus , A. violaceus and A. suturalis in the absence of a ventral projection of PII. In A. neocaledonicus the glandularia of the fourth coxal plates are located in the middle of these plates, and the female of A. rarus has differently shapes small dorsal platelets partially covered by the large plate. One female has the lateral platelets divided in two platelets. This aberration is also observed in the New Caledonian A. neocaledonicus , in which one of the females has only one of the lateral platelets divided (Smit 2002).

Figures

FIGURES 2 – 4. Aspidiobates vanuaticus n. sp., holotype male. 2 = ventral view; 3 = genital field; 4 = dorsal view. Scale lines: 2, 4 = 200 µm, 3 = 50 µm.

FIGURES 5 – 7. Aspidiobates vanuaticus n. sp., holotype male. 5 = capitulum + palp; 6 = I­leg­ 5 ­ 6; 7 = IV­leg­ 5 ­ 6. Scale lines = 50 µm.

FIGURES 8 – 10. Aspidiobates vanuaticus n. sp., paratype female. 8 = ventral view; 9 = genital field; 10 = dorsal view. Scaline lines: 8, 10 = 200 µm, 9 = 50 µm.