Scaptognathus insularis Otto, 2000

Pepato, Almir R., Tiago, Cláudio G. & Rocha, Carlos E. F., 2011, Psammophilous halacarid mites (Trombidiformes, Halacaridae) from the North Coast of São Paulo State, Brazil, Zootaxa 2823, pp. 47-60 : 52-54

Scaptognathus insularis Otto, 2000

( Figs. 4–5 )

Scaptognathus insularis Otto, 2000: 543 , fig. 6

Material examined. Paratype female (QMS105439), from coarse sand just above low tide mark, 10–20 cm below surface, Bylund Cay, Great Barrier Reef ( Australia), 21o47’S, 152o24’E, 17 April 1998, coll. J. C. Otto. Brazilian material: 1 female (Pepato’s collection), São Francisco, 14 January 2002; 2 females (Pepato’s collection), 23–37 cm, same locality and date; 2 females (Pepato’s collection), 10–20 cm, same locality, 15 March 2002; 3 females (MZSP-AC75–MZSP-AC77) and 5 females (Pepato’s collection), 20–30 cm, same locality, 27 May 2002; 1female (Pepato’s collection), 10–20 cm, same locality, 30 July 2002. All mites collected by researchers of BIOTA /FAPESP Program.

Description. Female. Idiosoma 238–278 long, 183–205 wide. Dorsal plates with pits. Pits and separating cuticle bars of almost same size ( Fig. 5 B). AD 97–108 long, 188–126 wide, anteriorly truncate, posteriorly convex. Pairs of ds-1 and pair of gland pores in smooth area of AD, delimited by dotted line ( Fig. 4 A). Pairs of ds-2 to 5 on striated cuticle. Eyes lacking. OC reduced to small sclerites, 10–13 long, 11–13 wide, with 1 pair of gland pores. PD anteriorly truncate, 82–85 long, 100–110 wide. Pairs of ds-6 and ds-7 on PD.

Ventral plates coarsely ornamented by polygonal pits, cuticle bars separating polygons narrower than average pit diameter ( Fig. 4 D–E). AE 72–75 long, 165–185 wide, with 1 pair of epimeral pores, 3 pairs of setae and shallow panels at apodemes. GA 92–101 long, 72–75 wide, including a pars membranosum 50–56 long, 63–70 wide. Three pairs of pgs on each side of GO. GO 33–41 long, 32–38 wide. Genital sclerites with 2 pairs of sgs.

Gnathosoma 205–218 long, 113–128 wide, gnathosomal length 0.77–0.87 times idiosomal length. Dorsum of gnathosoma evenly pitted throughout its anterior three quarter, with large and shallow foveae near posterior margin. Venter of gnathosoma with pits forming transverse bands between rows of broad and shallow depressions at muscular apodemes. Each side of anterior gnathosomal basis with areola built by relatively deep pits. Rostrum 88– 95 long, 28–30 wide at level of tritorostral setae, 47 wide at apical swelling.

Area corresponding to P2 with basal and proximal dorsal seta. Slit pointing out primitive anterior limit of P2. Segments of P3 and P4 bearing 2 scythe-like spines, 2 slender setae, 2 spurs, and 1 setula. Smaller of two spines of palp with protuberance ( Fig. 4 B, arrowed).

Leg chaetotaxy, bipectinate spines indicated by roman numerals: Leg I, 1,1,6(II),5(II),9(V),5(I); Leg II, 1,1,4,4(I),5(II),4(I); Leg III and IV 1,1,2,3,5(III),3. On telofemora I-II, 1 and 2 non-pectinate spines additionally to bipectinate spines. Tarsus I with 1 ventral bipectinate seta, solenidion, famulus and doublet pair of pas. Famulus– projection of tarsal cuticle with small hole at tip. Tarsus II with solenidion and doublet pair of pas. Tarsus III with anterior doublet and posterior singlet pas. Tarsus IV with pair of singlet pas. Lateral claws of all tarsi with small dorsal tooth each.

Remarks. Scaptognathus insularis is remarkable in bearing a protuberance on the smaller of the two palpal spines, a character not reported in the descriptions of other species. Comparing Brazilian individuals, Australian paratype, and original description, differences were found concerning AD ornamentation, leg spines, and idiosoma size. In the original description, the AD ornamentation was described as numerous irregularly shaped pits within polygons. In fact, the ornamentation of the specimens from Brazil ( Fig. 6 A) is slightly coarser than that observed on the Australian paratype, but not as suggested by original description figures ( Otto 2000). Both populations bear three and two spines on telofemora I and II, respectively. In the Australian material all are bipectinate whereas in Brazilian material only two among the three on telofemur I and none on telofemur II are conspicuously bipectinate. The Brazilian specimens are smaller(238–278) than those from Australia (415–375). Despite these differences, the Brazilian specimens are provisionally regarded as being conspecific to the Australian ones.

Figures

FIGURE 4. Scaptognathus insularis Otto, 2000, female: A, dorsum of idiosoma; B, tip of palp, note the protuberance on the smaller spine (arrow); C, venter of idiosoma; D, detail of AE; E, detail of GA; F, dorsum of gnathosoma; G, venter of gnathosoma; H, leg I in medial view; I, leg IV in lateral view; J, leg II in lateral view; K, leg III in lateral view. Scale bars: A, C, F, G = 50 µm; B = 10 µm, D, E, H – K = 25 µm.

FIGURE 5. Scaptognathus insularis Otto, 2000, female: A, AD of paratype female (QMS 105439); B, AD of Brazilian individual (MZSP-AC 77), note that the individual bears an asymmetrical abnormality, with gp- 1 duplicated. Scale bars = 50 µm.

FIGURE 6. Halacaroides antoniazziae sp. nov.: A, idiosoma of female in dorsal view; B, genitoanal area of male; C, idiosoma of female in ventral view; D, gnathosoma of female in ventral view; E, posterior epimeral plate of male. Scale bars: A, C = 50; B, D-E = 25 μm.