Copidognathus lutarius, BARTSCH, 2003

BARTSCH, I., 2003, Mangrove halacarid fauna (Halacaridae, Acari) of the Dampier region, Western Australia, with description of five new species, Journal of Natural History 37 (15), pp. 1855-1877 : 1868-1872

Copidognathus lutarius n. sp.

(figures 7, 8)

Material examined

H male, WAM T44107, Australia, Western Australia, east coast of the Burrup Peninsula, Watering Cove , turf on Avicennia pneumatophores, 8 August 2000, coll. I. Bartsch.

P: three males, WAM T44108, T44111 and T44112 , two females, WAM T44109 and T44113 , one female, one protonymph, WAM T44110 , collecting data same as in holotype. One female and male, SMF, collecting data same as in holotype. One female and male, ZMH, collecting data same as in holotype.

Etymology. The name is derived from lutum (Latin), mud, lutarius , living in mud.

Description

Male. Idiosoma 435–465 m m long, holotype 465 m m long, 315 m m wide. Idiosoma uniformly coloured due to dark greyish green gut contents; with three spots of eye pigment. Porose areolae very weakly demarcated and hardly raised; areolae with pycnic rosette pores with scattered canaliculi and minute ostia, remainder of plates with foveae which include canaliculi (figure 7D). AD 134 m m long, 155 m m wide; with three areolae (figure 7A). Posterior margin of plate slightly excavate. OC 130 m m long, 90 m m wide; with two corneae; pore canaliculus within lateral margin. PD 297 m m long, 229 m m wide; with two pairs of medial and two pairs of lateral costae. Gland pores inconspicuous. Dorsal setae very small; pair of ds- 1 in middle of AD ; ds-2 either within margin of OC or within striated integument immediately adjacent to OC; ds-3 to ds-5 on PD adjacent to medial costae; ds-4 and ds-5 level with insertion of legs III and IV, respectively. Adanal setae adjacent to posterior margin of PD.

Ventral plates pierced by canaliculi which are arranged within polygons. AE 150 m m long (camerostomal membrane included), 279 m m wide; posterior margin truncate (figure 7B). Ventral setae longer than dorsal setae; AE generally with three pairs of setae (in holotype a small additional seta present) and long, slit-like openings of epimeral pores (figure 7F). PE 209 m m long; with one dorsal seta and three ventral setae. GA 225 m m long, 183 m m wide; anterior margin truncate. GO 72 m m long, 55 m m wide. Two anterior pairs of sgs seta-like, two posterior pairs spur-like. Holotype with nine pairs of pgs, arranged as illustrated (figure 7C). With single pair of genital acetabula. Spermatopositor 130 m m long (to base of furca), 100 m m wide; reaching almost to anterior margin of GA.

Gnathosoma 115 m m long, 110 m m wide. Rostrum triangular at ventral aspect (figure 7E); with a length of 40 m m much shorter than gnathosomal base. Tectum truncate. Tip of rostrum not extending beyond end of P-3. Palps short, P-2 with one dorsal seta (figure 7G); P-4 with three setae in basal whorl. Maxillary setae short, one pair on gnathosomal base and one pair on rostrum. Rostral sulcus reaching backward just beyond level of pair of maxillary setae.

Leg I hardly wider than following legs. Integument of basifemur to tibia I (figure 8A) and II laterally punctate, medially almost smooth, on legs III and IV trochanters, telofemora, genua and tibiae laterally punctate. Telofemora I and II 2.4–2.5 times longer than high. Leg chaetotaxy from trochanter to tarsus: leg I, 1, 2, (4–)5, 4, 7, 7; leg II, 1, 2, 5, 4, (6–)7, 4; leg III, 1, 2, 2, 3, 5, 4; leg IV, 0, 2, 2, 3, 5, 3. Tibiae I and II (figure 8H, I) each with two conspicuously wide and distinctly bipectinate setae and one slender, smooth seta; tibiae III and IV (figures 7J, K, 8F) each with one wide, bipectinate seta and one slender smooth seta. Tarsus I with ventral seta situated level of half-way between dorsal fossary setae (figure 8B), pair of single eupathidia and pair of doubled pas; tarsus II with pair of doubled pas (figure 8D); tarsi III and IV (figure 8E) each with long, setiform lateral pas, medial pas lacking. Solenidia on tarsi I and II short (figures 8C and D), famulus on tarsus I short, a lamellar projection. Distance between two basal setae on tarsus III equals height of tarsus.

Claws long, slender, at low magnification apparently smooth, at higher magnification (oil immersion) few delicate tines visible (figure 8B). Median claw present, bipectinate.

Female. Idiosoma 466–490 m m long. Anterior margin of GA rounded (figure 8G). Interval between GO and anterior margin of GA equalling length of GO. GA with three pairs of pgs arranged as illustrated. Ovipositor extending to level with anterior pair of pgs.

Protonymph. Porose areolae of dorsal plates pierced by canaliculi; areolae delimited from remainder of plate that bears foveae and canaliculi (figure 8H). PD distinctly smaller than in adults; anteriorly narrowed (figure 8I); with ds-3 to ds-5 and pair of medial costae. PE with one dorsal and two ventral setae. Genital plate short, rectangular (figure 8J), with pair of internal acetabula (figure 8M). Leg chaetotaxy: leg I, 1, 2, 3, 4, 5, 7; leg II, 1, 2, 3, 4, 5, 4; leg III, 1, 1, 2, 3, 5, 4; leg IV, 0, 1 + 2 (basi- + telofemur), 3, 5, 3. Tibiae I (figure 8K) and II each with wide, bipectinate seta; tibiae III and IV (figure 8L) with ventromedial seta only slightly wider than ventrolateral seta, the few delicate denticles seen only at high magnification.

Remarks

Copidognathus lutarius differs from other Copidognathus species by: (1) a size larger than in the majority of species, which have an idiosomal length of approximately 250–350 m m; (2) its uniformly dark gut in contrast to a yellowish content with orange or brown spots; (3) a short triangular rostrum and small palps, whereas in other Copidognathus the combinations found are both rostrum and palps elongate, or rostrum short, triangular but surpassed by distinctly longer palps, or palps short but rostrum elongate with almost parallel-sided margins; (4) the ventromedial seta on tarsus I moved towards the apex, whereas in the majority of species this seta is close to the basis of the segment; (5) the short, bacilliform solenidia on tarsi I and II, in other species these are long and setiform; (6) the absence of the medial parambulacral seta on each of tarsus III and IV that is present and often spiniform in other species.

Copidognathus lutarius demonstrates an unusual change from protonymph to adult in the shape of the ventromedial seta of tibiae III and IV. In protonymphs this seta is slender, hardly wider than the ventrolateral seta and very delicately pectinate, whereas in adults the seta is wide and strongly bipectinate. In general in protonymphs of Copidognathus , the setae of juveniles are somewhat smaller and more delicate than in adults but without any marked difference in the pectination. The raised areolae of the dorsal plates are more distinctly demarcated in protonymphs than in adults.

The gut content of Copidognathus lutarius is uniformly dark; the food is not known.