Copidognathus parvulus, Bartsch, Ilse, 2007

Bartsch, Ilse, 2007, Halacarid mites (Acari: Halacaridae) from Esperance (Western Australia), description of two new Copidognathus species, Zootaxa 1435, pp. 41-49 : 45-48

Copidognathus parvulus spec. nov.

Figs 14–28

Material examined. Holotype male, WAM T78347, Western Australia, Esperance, Duke of Orleans Bay, 33°55’S, 122°35’E, corallines on demosponge, just below low water line, 17 February 2003.

Diagnosis. Length 290 µm. On dorsal plates areolae with rosette pores distinctly delimited from rather smooth remainder of plates. AD with three small porose areolae; on PD pair of marginal costae separated from transverse porose areola in posterior margin. Ventral plates with small, porose areolae. Gnathosoma slender; rostrum long, extending to about middle of P-4. Legs slender, telofemora, genua and tibiae with articular membranes, tarsi with fossa membranes. Telofemora III and IV with 2/1 and 2/0 dorsal/ventral setae. Tibiae I to IV with 2, 2, 1, 0 bipectinate setae and 1, 1, 1, 2 slender ventral setae. Tarsi III and IV with four and three dorsal setae, respectively.

Description. Length 290 µm, width 164 µm. Idiosoma heavily armoured ( Fig. 14 ), with narrow, coarse striae between the plates. Most parts of dorsal plates smooth, except for clearly demarcated porose areolae with rosette pores and scattered shallow foveae in anterior part of AD and within reticulate lateral margin of OC. Rosette pores with small surficial ostium and four to six canaliculi in deeper integumental layers. AD longer than wide, length 92 µm, width 70 µm; shape octagonal, anterior margin with truncate lamella, posterior margin truncate. Anterior porose areola transversely oblong, two posterior areolae round and immediately adjacent; scattered shallow foveae between anterior and paired areolae ( Fig. 16 ). Pair of porose areolae close together at 0.54. Length of OC 82 µm, width 52 µm, posteriorly with small ‘tails’, each plate with two large corneae, gland pore level with posterior cornea, pore canaliculus slightly posterior to gland pore; a porose areola medial to corneae; integument along lateral edge of OC raised and with foveae but without canaliculi ( Fig. 17 ). Length of PD 180 µm, width 106 µm; anterior margin ovate, extending between OC. PD with pair of porose costae near lateral margin of plate, costae far from reaching anterior margin of PD. Rosette pores present from level of 0.24 to 0.75; costae two rosette pores wide in anterior half, a single rosette pore wide in posterior half. Area between costae and posterior porose areola slightly raised. One pair of gland pores in lateral margin of costae halfway between ds-4 and ds-5 and somewhat anterior to the level of insertion of leg IV. Pair of ds-1 on AD in margin of pair of porose areolae; ds- 2 in striated integument; ds-3, ds-4 and ds-5 on PD, ds-3 anterior to costae, ds-4 and ds-5 within costae. Adanal setae in posterior margin of PD.

Ventral plates with small, distinctly delimited porose areolae, otherwise smooth. On AE porose areolae anterior to insertion of leg II. PE with two marginal areolae, one each anterior to insertions of legs III and IV, and one ventral areola medial to insertion of leg III. On GA areolae on either side of GO ( Fig. 15 ). Length of AE 110 µm, width 139 µm; posterior margin truncate; AE with large epimeral processes lamelliform flanking bases of trochanters I and II ( Fig. 18 ). Length of PE 139 µm, extending beyond insertion of leg IV. Length of GA 147 µm, width 100 µm, anterior margin truncate. GO in posterior half of GA. Length of GO 37 µm, width 27 µm. Distance between anterior margin of GO and that of GA 1.9 times length of GO. Twenty-six perigenital setae arranged in a ring around GO. Genital sclerites with four pairs of subgenital setae, two anterior pairs setiform, two posterior pairs spur-like ( Fig. 19 ).

Gnathosoma long and slender; length 145 µm, width 45 µm. Rostrum extending to about middle of P-4 ( Figs 20, 21 ), its length about twice that of gnathosomal base. P-2 longer than P-4; P-2 with one dorsal seta, P-4 with three setae in basal whorl, one setula and two spurs at apex. Tectum triangular, its margin dentate ( Fig. 20 ). Lateral flank of gnathosomal base with rosette pores, dorsal flank with scattered, small foveae.

Legs slender, heavily sclerotized, ventral integument markedly thicker than dorsal one ( Fig. 26 ). Surface of telofemora and tibiae covered with small cuticular droplets, that of telofemora also minutely reticulate. Ventral margin of telofemora apparently delicately crenulate, due to small cuticular droplets on the surface. Telofemora rather short, on all legs shorter than tibiae. Telofemora I to IV 2.5, 2.3, 2.0 and 2.2 times longer than high, respectively. Telofemora, genua and tibiae with large articular membranes, tarsi with fossa membranes ( Figs 22–25 ). Trochanters III and IV each with small medial lamella ( Figs 24, 25 ). Distal margin of telofemora I and II with minute spiniform dorsal lamella. Leg chaetotaxy: leg I, 1, 2, 5, 4, 7, 7; leg II, 1, 2, 5, 4, 7, 4; leg III, 1, 2, 2, 3, 5, 4; leg IV, 0, 2, 3, 3, 5, 3. Tibiae I to IV with 2, 2, 1, 0 bipectinate and 1, 1, 1, 2 smooth ventral setae. Solenidion on both tarsus I and II 16 µm long and on dorsolateral fossa membrane ( Figs 27, 28 ). Basal seta on tarsus III removed from fossary seta by height of tarsus ( Fig. 29 ). Tarsus I with pair of doubled pas, tarsus II with single pas on either side; tarsi III and IV with setiform lateral pas and short, bristlelike medial pas.

Claws of all tarsi with accessory process and pecten, the latter with numerous delicate tines. Pecten not extending to base of claw.

Etymology. It is a rather small and slender species, hence the name parvulus (Latin) , small.

Remarks. The most obvious combination of characters is: rostrum long and slender; porose areolae of dorsal and ventral plates distinctly delimited; AD with three small areolae and pair of glp-1 removed from lateral margin; PD with pair of rather short costae not fused with large posterior areola.

Copidognathus attalus Bartsch, 1999 is strikingly similar to C. parvulus and shares characters such as (1) porose areolae of dorsal and ventral plates distinctly delimited, (2) three small areolae on AD and (3) glp-1 and ds-1 immediately adjacent. Marked differences are in the ornamentation of the plates and the shape of the rostrum. The porose areolae of the dorsal plates are wider in C. parvulus than in C. attalus ; in C. parvulus the integument of the dorsal and ventral plates is smooth outside the porose areolae, in C. attalus the dorsal plates are reticulate and the ventral plates bear a delicately foveate ornamentation. The rostrum of C. parvulus is very long, about twice the length of the gnathosomal base, and extends far beyond the base of P-4, the rostrum of C. attalus is slightly longer than the gnathosomal base, just reaching the end of P-3.

Distribution. Western Australia, Esperance. The only specimen collected lived amongst corallines on a demosponge.

Figures

FIGURES 14 – 21. Copidognathus parvulus spec. nov., male, 14, idiosoma, dorsal; 15, idiosoma, ventral; 16, anterior part of idiosoma with AD, dorsal; 17, ocular plate; 18, part of AE with epimeral pore; 19, genital opening; 20, gnathosoma, dorsal; 21, gnathosoma, ventral. (ds- 1, first dorsal seta; glp, gland pore, pc, pore canaliculus) Scale = 50 µm.

FIGURES 22 – 29. Copidognathus parvulus spec. nov., male, 22, leg I, medial; 23, leg II, medial; 24, leg III, medial; 25, leg IV, medial; 26, telofemur to tibia IV, lateral (optical section in dotted line); 27, part of tibia and tarsus I, lateral (medial setae and claw omitted); 28, tarsus II, lateral (medial setae and claw omitted); 29, part of tibia and tarsus III, lateral (medial setae and claw in broken line). Scale = 50 µm.