Macroscapha walterae, Brandão, 2010

Brandão, Simone N., 2010, Macrocyprididae (Ostracoda) from the Southern Ocean: taxonomic revision, macroecological patterns, and biogeographical implications, Zoological Journal of the Linnean Society 159 (3), pp. 567-672 : 632-635

MACROSCAPHA SP. AFF. MH. WALTERAE SP. NOV.

( FIG. 34 )

Material: 4 live specimens.

1 A M (SNB 0569-DNA 276), ANDEEP I, # 41-3-E, ZMH K-41478; 2 (A-?1) (SNB 0570-DNA 277), 1 (A-?2), ANDEEP I, # 46-7-S, ZMH K-41479.

Distribution ( Fig. 34 ): Recent. Scotia Sea, 2359 – 2893 m.

Valve measurements ( Fig. 34 ): A L 2.03 mm, H 0.82 mm; (A-?1) L 1.50–1.63 mm, H 0.64–0.68 mm; (A–?2) L 1.30 mm, H 0.54 mm.

Remarks: Macroscapha sp. aff. Mh. walterae is similar to Mh. walterae in the valve outline and in the asymmetrical Fu. Otherwise, both species differ genetically, i.e. the pairwise distances of the COI and ITS markers are typical of distinct species of Macroscapha (S. N. Brandão & I. Schön, unpubl. data). As most of the soft parts of the only adult specimen available were used for DNA extraction, further morphological study and the description of this new species had to be postponed.

INFORMAL GROUP MACROSCAPHA TENSA- OPACA

( FIGS 43–58 )

Remarks: Both of the species Macroscapha tensa (G. W. Müller, 1908) and Mh. opac a Maddocks, 1990 were previously thought to be widely distributed: the former species was reported from the Antarctic and Subantarctic regions of the SO (Pacific and Atlantic Sectors), and the latter species was recorded from the high Antarctic region of the Atlantic Sector of the SO to the subtropical south-western Atlantic ( Fig. 43 ). After the study of part of the material involved in these previous records it was possible to conclude that at least five species are included in what previous authors thought to be only two species: Mh. opaca Maddocks, 1990 , Mh. sp. nov. 1, Mh. sp. nov. 2, Mh. sp. nov. 3, and? Mh. sp. ( Mh. tensa is herein considered a nomen dubium). In addition, three new species were present in the new samples collected in the Atlantic Sector of the SO – Mh. cactus sp. nov.; Mh. falcis sp. nov., and Mh. solecavai sp. nov. –which are morphologically similar to Mh. opaca and Mh. tensa , and are therefore included in this informal group.

Species included herein present (1) an elongate, often rectilinear outline, with acutely pointed posterior angle; (2) podomeres IV and V (= palp podomeres III and IV) of the female appendage V present medium-sized, thick claws (as in Figs 51A, 51E ); (3) symmetrical furcal rods (as in Figs 51B, 51J ). Moreover, an interesting character that unites these species is the (4) ‘reverse’ valve overlap; the LV is larger than and overlaps the RV ventrally, antero-, and posterodorsally ( Figs 49Q–R , 54M–N ). Noteworthily, in only the adult and juvenile females of Mh. opaca from the Ross Sea (stations ‘H in 4’ and ‘H in 5’), the right valves are always larger than and overlap the left valves. Additionally, (5) the hemipenises are subtrapezoidal with a copulatory process composed of three segments, the most proximal one is elongate, fairly straight, and quite invariable amongst species; the second and third segments are shorter and vary greatly in shape ( Fig. 44 ). These two latter segments are the most important characters differentiating amongst the species of the informal group Macroscapha tensa-opaca .

0.80 1.10 1.40 1.70 2.00 2.30 2.60 0.80 1.10 1.40 1.70 2.00 2.30 2.60 0.80 1.10 1.40 1.70 2.00 2.30 2.60

Figures

Figure 34. Geographical distribution and height ¥ length scatter plot of valves of Macroscapha inaequalis, Macroscapha inaequata, Macroscapha walterae sp. nov., Macroscapha sp. aff. walterae sp. nov., and Macroscapha sp. (of the informal group Macroscapha turbida). Both records of Mh. inaequata (Maddocks, 1990) from the Pacific Sector of the Southern Ocean are herein considered dubious because they are based on only one female (Ross Sea) and one very large teratological adult of indeterminable sex (south-west Pacific Basin; Maddocks, 1990).

Figure 43. Geographical distribution and height ¥ length scatter plot of valves of species of the informal group ‘Macroscapha tensa-opaca’. Macroscapha opaca herein – material studied herein; Mh. opaca Maddocks – material studied by Maddocks (1990).

Figure 44. Copulatory rods of the hemipenis of the species of the ‘Macroscapha tensa-opaca’ informal group. Macroscapha cactus sp. nov.: A, holotype adult male (SNB 0041, ZMH K-41483). Macroscapha falcis sp. nov.: B, paratype adult male (SNB 0104-DNA 7, ZMH K-41496). Macroscapha solecavai sp. nov.: C, paratype adult male (SNB 0560-DNA 267, ZMH K-41499). Macroscapha opaca Maddocks, 1990: adult male (SNB 0045, ZMH K-40825). Macroscapha sp. nov. 1: E, adult male (SNB 0859, ZMH K-33305). Macroscapha sp. nov. 2: F, adult male (SNB 0866, ZMH K-34505). Scale bar = 100 Mm.

Figure 49. Valves of species of the informal group ‘Macroscapha tensa-opaca’. Macroscapha cactus sp. nov.: A, B, holotype adult male (SNB 0041, ZMH K-41483). Macroscapha falcis sp. nov.: C, D, paratype adult male (SNB 0472-DNA 179); G, H, subfossils (A-1); Q, subfossil (A-1), (ZMH K-41496). Macroscapha solecavai sp. nov.: E, F, paratype adult male (SNB 0560-DNA 267); J, K, paratype (A-1) female (SNB 0568-DNA 275, ZMH K-41499); I, paratype subfossil (A-?3, ZMH K-41498). Macroscapha opaca Maddocks, 1990: L, M (A-1) female (SNB 0506-DNA 213, ZMH K-42018). N, P, subfossil (A-2) (ZMH K-41495); O, subfossil (A-1) (ZMH K-40831). Macroscapha sp. nov. 1: R, subfossil A, (ZMH K-33305). A, C, E, left valve (LV) internal view; B, D, F, right valve (RV) internal view; G, J, L, N, RV external view; H, I, K, M, O, P, LV external view; Q, RLV dorsal view; R, RLV ventral view. Scale bar = 500 Mm. The arrows point towards the anterior of the animal.

Figure 51. Soft parts of species of the informal group ‘Macroscapha tensa-opaca’. Macroscapha falcis sp. nov.: A, paratype adult female (SNB 0852); B, paratype adult male (SNB 0470-DNA 177); C, D, paratype adult male (SNB 0466-DNA 173); E, paratype adult female (SNB 0873), (ZMH K-41496). Macroscapha solecavai sp. nov.: F, G, paratype adult male (SNB 0515-DNA 222, ZMH K-41498). Macroscapha sp. nov. 1: H, I, adult male (SNB 0859, ZMH K-33305a). Macroscapha sp. nov. 2: J, adult male (SNB 0866, ZMH K-34505). A, E, female appendage V; B, J, furca; C, D, F–I, male appendage V. Scale bars = 100 Mm.

Figure 54. Valves of Macroscapha opaca Maddocks, 1990. A, adult female (SNB 0664, ZMH K-41489); B, adult male (SNB 0380), (ZMH K-41490); C, adult female (SNB 0044, ZMH K-40825); D, adult male (SNB 0499-DNA 206, ZMH K-42018); E, adult female (SNB 0144, ZMH K-41332); F, adult male (SNB 0033, ZMH K-40831); G, adult female (SNB 0858, ZMH K-40830); H, adult female (SNB 0049, ZMH K-40834); I, adult male (SNB 0107 ZMH K-41331); J, adult male (SNB 0754, ZMH K-41382); K, L, adult female (SNB 0055, ZMH K-40828); M, N, subfossils (ZMH K-41495). A–J, left valve (LV) external view; K, LV internal view; L, right valve (RV) internal view; M, closed carapace (RLV) dorsal view; N, RLV ventral view. Scale bars = 500 Mm. The arrows point towards the anterior of the animal.