Pseudoctomeris sulcata (Nilsson-Cantell, 1932)

Pitriana, Pipit, Valente, Luis, von Rintelen, Thomas, Jones, Diana S., Prabowo, Romanus E. & von Rintelen, Kristina, 2020, An annotated checklist and integrative biodiversity discovery of barnacles (Crustacea, Cirripedia) from the Moluccas, East Indonesia, ZooKeys 945, pp. 17-83 : 17

Pseudoctomeris sulcata (Nilsson-Cantell, 1932) Figure 7a-h , Table 1: species no. 50

Octomeris sulcata Nillson-Cantell, 1932: 8; Newman and Ross 1976: 40.

Pseudoctomeris sulcata : Poltarukha 1996: 988; Chan et al. 2009a: 156, fig. 131.

Material examined.

Ambon Island: 4 specimens, MZB Cru Cir 073, Leahari, 3°42'45.3"S, 128°16'16.5"E, coll. P. Pitriana, 14 Jan 2016; 2 specimens, MZB Cru Cir 074, Hatu, 3°43'52.7"S, 128°02'51.4"E, coll. Adin, 20 Sep 2017.

Diagnosis.

Shell with eight plates; compound rostrum; scutum and tergum fused; mandible tridentate; multi-jointed caudal appendage present.

Description.

Shell externally white, internally black; eight plated, rostrum partially fused with rostrolaterals giving external appearance of six plates (Fig. 7a-b ); basis membranous, calcareous; orifice rhomboidal; scutum and tergum thick (Fig. 7c, d ); maxilla triangular, maxillule not notched (Fig. 7g ), mandible with three teeth (Fig. 7h ), labrum concave, with blunt teeth; cirrus VI with long, multi-segmented caudal appendages. Ranges of basal length 16.2-16.7 mm, basal width 11.5-15.0 mm, height 7.4-7.7 mm. Orifice length 5.5-7.9 mm, orifice width 4.3-6.1 mm (measurements for two specimens are presented in Suppl. material 1: Table S6).

Distribution.

Pseudoctomeris sulcata was previously recorded from southern Japan, China, and Taiwan ( Jones et al. 2001; Poltarukha and Zevina 2006). In this study, P. sulcata was found on Ambon Island at Leahari and Hatu on rocks and shells of Tetraclita squamosa (a map with the occurrence of Pseudoctomeris sulcata in the Moluccas is shown in Suppl. material 1: Fig. S2).

Remarks.

Externally, the fused rostrum and rostrolaterals are six-plated, but the sutures are visible internally ( Poltarukha 1996). Morphologically, Pseudoctomeris sulcata shows features of the scutum and tergum similar to those of representatives of the family Pachylasmatida. However, the species can be distinguished by its tridentate mandible and the presence of multi-jointed caudal appendages (Poltarukha 2006). A previous molecular study showed that P. sulcata clustered together with members of the family Pachylasmatidae , not with members of the Chthamalidae ( Chan et al. 2017). According to Chan et al. (2017), P. sulcata is an intertidal species of the Pachylasmatidae , previously believed to be an exclusive deep-sea taxon.

Figures

Figure 7. Pseudoctomeris sulcata (Nilsson-Cantell, 1932) (MZB Cru Cir 073 - 4) a upper view b side view c external view of scutum and tergum d internal view of scutum and tergum e cirrus I f cirrus III g maxillule h mandible. Scale bars: 4 mm (a-b); 2 mm (c-d); 1 mm (e); 2 mm (f), 0.5 mm (g-h).