Bythocypris praerenis
Carapace very large, sub-reniform, maximum height anterior to mid-length, posterior angle obtuse. Lateral surface smooth. RV with anterodorsal margin straight, ventral margin concave. LV outline less sinuous, more evenly rounded, with arched dorsal margin. Calcified inner lamella wide; zone of concrescence fairly narrow, with numerous straight, short radial pore canals. Radial pore canals simple, with or without rim. Three anterior plus one posterior adductor muscle scars. In dorsal view, carapace elongate, maximum width at mid-length.
Antennula robust, with short and thick podomeres, with not very long setae; suture between podomeres II and II incomplete. AII robust, with short and thick podomeres; exopodite with 1 short and 2 long setae; podomere VI with 1 anterodorsal, very short seta, 1 long claw, 1 medium-sized posterodorsal fused claw, and 2 medium-sized posterodistal setae. Base of mandibula with 1 anterodorsal seta, masticatory process with 1 dorsal, bifurcate tooth, 4 trifurcate teeth, plus several short setae; exopodite with 1 very long and 2 long feathered setae; podomere IV of palp with 4 medium-sized setae and 3 medium-sized claws. Vibratory plate of maxillula with 7 strahlen and around 25 setae; palp with 3 long, dorsal, setae 2 long, ventral setae and 1 distal, medium-sized, finely feathered claw. fifth limb robust, with short and thick podomeres; vibratory plate with 4 strahlen and 9 or 10 feathered setae. Furca with 3 to 6 tiny proximal setae, and 3 medium-sized feathered distal seta. One short seta between furca‘s rods. Genital lobe ovate-subtriangular, with scoop-shaped process attached to coiled tube.
Carapace very large, sub-reniform; maximum height anterior to mid-length; with numerous, straight, short marginal pore canals. Podomere VI of antenna with 1 anterodorsal, tiny seta, 1 long claw, 1 medium-sized, posterodorsal, fused claw, and 2 medium-sized, posterodistal setae. Podomere IV of mandibula palp with 4 medium-sized setae and 3 medium-sized claws. Vibratory plate of maxillula with 7 strahlen and 25 feathered setae. Furca with 3 to 6 tiny, proximal setae and 3 medium-sized, finely feathered, distal setae. Genital lobe ovate-subtriangular, with a scoop-shaped internal process attached to short tube.
Bythocypris reniformis (Brady, 1880) sensu Puri and Hulings, 1976.
Holotype, LV, L 1.60mm, H 0.77mm; RV, L 1.60mm, H 0.72mm.
Paratypes, LV, A L 1.60–1.81mm, H 0.77–0.90mm; (A-1) L 1.32–1.44mm, H 0.64–0.71mm; (A-2) L 1.00–1.14mm, H 0.53–0.58mm; (A-3) L 0.84mm, H 0.44mm.
Bythocypris praerenis sp. nov. is similar to B. reniformis sensu Puri and Hulings, 1976, but the former species presents: (1) larger height to length ratio; (2) larger size (1.60 to 1.76mm instead of 1.09mm); (3) more concave ventral margin; (4) and wider calcified inner lamella, with straight, short marginal pore canals (instead of ramified).
The only three species of Bythocypris recorded from the high Antarctic region of the Southern Ocean (B. eltanina Maddocks, 1969, B. spiriscutica Maddocks, 1969 and B. promoza Maddocks, 1973) plus B. elongata Brady, 1880, B. mozambiquensis Maddocks, 1969, B. prolata Maddocks, 1969 are more subtriangular than B. praerenis. Bythocypris affins affins Brady, 1886 (sensu Brady & Norman 1889: 242, Fig.) is smaller and has a more rounded, less sinuous RV in lateral view, and is also wider, more ovate in dorsal view. Bythocypris affins madagascarensis Maddocks, 1969 is higher in relation to length with the maximum height of LV at midlength instead of conspicuously anterior to it.
For the soft part anatomy, I follow Horne et al., 2002 (Horne DJ, Cohen A, Martens K. 2002. Taxonomy, morphology and biology of Quaternary and living Ostracoda. In: Holmes JA, Chivas AR, editors. The Ostracoda. Applications in Quaternary Research. Washington, DC: American Geophysical Union. p 5-35.).
We use the following terms for the limbs/furca from anterior to posterior with alternative names in parenthesis:
antennula (antenna I, Aa, AI, first antenna)antenna (antenna II, AII, Au, second antenna)mandibula (mandible, Md)Maxillula (first maxilla, maxilla I, maxillule, MxI, Mxu)Fifth limb (ApV, Appendage V, first thoracic leg, maxilla, maxilla I, MxI, Mxu, maxilliped, clasper (for males), P1, second maxilla, walking leg)Sixth limb (ApVI, Appendage VI, first thoracic leg, second thoracic leg, P2, walking leg)Seventh limb (ApVII, Appendage VII, cleaning limb, P3, second thoracic leg, third thoracic leg, walking leg)Male copulatory limb (eighth limb, hemipenis, uropod). Whether the Male copulatory limb is homologous to a crustacean limb remains controvertial.Furca (caudal rami, Fu, furcal rami, uropods). The homology of the podocopan furca (anterior to the anus) to a myodocopan furca (posterior to the anus) remains controversial. Similarly, the homology of the ostracod furca to the furca of other crustaceans remains controvertial.
Antennula 1(0/0), 2(0/.1), 3(0/.1-2), 4(.1/0), 5(.2/.2), 6(.2/.2-3), 7(0/0:4-5). Antenna 1(0/0:2i), 2(1/0), Exopodite(0/0:3), 3(0/.3.2), 4(.2r,2./0), 5(.1.1c./.1r.1c,1), (1r,1c,2,1fc). Mandibula palp 1(0/.1.:1i), 2(.1.2./1:1i), 3(.5./.1:2i), 4(.2./0:3c,2). Maxillula 1(.1.2.2-3/0:1i), 2(.2/0), 3(.1/0), 4(.1/0), 5(0/0:1r,1c,1r). Sixth and seventh limbs 1(.1.1.2/0), 2(.2/0), 3(.1/0), 4(.1/0), 5(0/0:1r,1c,1r).
Chaetotaxy formula follows Schornikov and Keyser (2004, The morphology and classification of Paradoxostomatinae (Ostracoda) from the nearshore zone of Madeira and the Canary Islands. Revista Española de Micropaleontologia 36: 57-81.) : "Figures without parentheses = podomeres numbered from proximal to distal; + = junction of podomeres. Figures within parentheses = number of setae: numerator = setae on dorsal margin; denominator = setae on ventral margin; integer figures = lateral, medial or apical armature elements, from dorsal to ventral. Figures within parentheses without indexes = normally development setae; r = rudimentary; c = claw-shaped seta or claws; s = sensory seta; p = plumose seta or ray; re = reflexed seta or ray; a = atriumwards ray; t = tooth or tooth-shaped seta; l or m = lateral or medial seta. A dot indicates the presence of an interval between setae or between podomere ends; a colon indicates apical, lateral or medial setae; hyphen indicates variable elements. Commas are used for the sake of clarity e.g. to separate symbols by unarmed podomeres or setae without indexes."
(see an example of the chaetotaxy formula in the figure "EXAMPLE CHAETOTAXY" in this species page)
6 live specimens, 318 valves.
Holotype: 1 A F (SNB 0388), ANDEEP III # 133–2–E, ZMH K-41356.
Paratypes:
1 A F (SNB 0387), 1 (A-1) (SNB 0209), 5 RV, 7 LV, 1 RLV, ANDEEP III # 133–2–E, ZMH K-41328; 23 RV, 26 LV, 20 RLV, 157 V, ANDEEP II, # 132–2–S, ZMH K-41329;
3 (A-1) (SNB 0275-7), 51 V, 2 R.LV, ANDEEP II, # 133–3–E, ZMH K-41330; 2 RLV, 1 LV, ANDEEP II, # 133–3–S, ZMH K-41357
A, adult; (A-1), (A-2), (A-3), juvenile instars; E (after a station number), epinet of the epibenthic sledge; F, female; H, Height; L, length; LV, left valve; M, male; RV, right valve; S (after a station number), supranet of the epibenthic sledge; SNB, specimen number as catalogued by the Brandão, S. N. (throught this number, it is possible to assign correctly the valves of a single specimen kept in a micropaleontological slide to their dissected appendages in a glass slide); V, valve; ZMH, Zoologisches Institut und Museum, University of Hamburg (Germany); ZMH K-, abbreviation of the Crustacea collection of the Zoologisches Institut und Museum, University of Hamburg (Germany); #, station number.
2008 Bythocypris praerenis Brandão, sp. nov.: 407-412, Figs. 22-23, 24.A-L, 25-26.
For its resemblance to B. reniformis Brady, 1880.
Northwestern Weddell Sea, Southern Ocean (Atlantic Sector), 1123 to 2084m.
Brandão (2008)
Brandão, S. N., 2008. New species of Bairdioidea (Crustacea, Ostracoda) from the Southern Ocean and discussions on Bairdoppilata simplex (Brady, 1880), ?Bairdoppilata labiata (Müller, 1908) and Bythopussella aculeata (Müller, 1908). Zootaxa, 1866: 373–452,
(this publication can be freely downloaded from http://www.mapress.com/zootaxa/2008/f/zt01866p452.pdf)