Fabaeformiscandona paterea, Smith & Janz, 2008
|
publication ID |
https://doi.org/ 10.1080/00222930802361030 |
|
persistent identifier |
https://treatment.plazi.org/id/6530807D-EC2F-FFAD-AFC8-FB05FC37FC67 |
|
treatment provided by |
Carolina |
|
scientific name |
Fabaeformiscandona paterea |
| status |
sp. nov. |
Fabaeformiscandona paterea sp. nov.
( Figures 2 View Figure 2 G–J, 4 and 5)
Type locality
Lake Biwa – eastern side of the southern part of the north basin, locality 35 (35 ° 14922.20N; 135 ° 58913.70E), depth 25 m, substrate poorly sorted mud, sand, gravel and organic detritus.
Type material
Holotype LBM 1430003287 View Materials , male, appendages mounted on a glass slide, valves stored in a micropalaeontological cavity slide . Allotype LBM 1430003288 View Materials , female, appendages mounted on a glass slide, valves stored in a micropalaeontological cavity slide . Paratype LBM 1430003285 View Materials , male, appendages mounted on a glass slide, valves stored in a
micropalaeontological cavity slide. Paratype LBM 1430003286 View Materials , female, appendages mounted on a glass slide, valves stored in a micropalaeontological cavity slide .
Derivation of name
From the Latin patera (feminine) meaning a broad, flat dish, referring to the distinctive shape of the FRO projection ( Figure 5G View Figure 5 ).
Diagnosis
Carapace elongated with maximum height at posterior third marked by angular dorsal hump; either side of hump dorsal margin straight to slightly curved. Posterior margin joins dorsal margin at conspicuous angle. FRO protrusion large, flattened, and rounded. Hp m process with rounded, slender bulge distally, a lobe pointed distally and steeply curved along top edge, almost straight along bottom edge. UR Sp seta short.
Description
Male carapace length 1028–1035 Mm, height 457–471 Mm, H/L50.44–0.46, female length 937–951 Mm, height 394–437 Mm, H/L50.42–0.46. Carapace elongate and rectangular, with maximum height marked by dorsal hump at posterior third. Either side of hump dorsal margin straight to slightly curved. Anterior margin equally rounded. Posterior margin angular above mid-height, more rounded towards ventral margin. Ventral margin concave. Dorsal view of female with equally rounded posterior and anterior margins. Calcified inner lamella wide anteriorly, narrow posteriorly. Lateral view of carapace similar in both sexes, but males slightly more rounded along posteroventral margin than females. Both valves of female with large posterodorsal flaps; left valve also with smaller anterodorsal flap. Colour white.
An1 with eight segments, first two of which are fused together forming one large movable article, supporting two dorsal setae and two long ventral–apical setae. Third segment quadrate with one relatively long dorsal–apical seta. Fourth segment small and quadrate with one dorsal–apical seta. Fifth and sixth segments elongate, each with two long dorsal–apical setae and one short ventral–apical seta. Seventh segment with two long and two short apical setae. Eighth segment with one long and two short setae and short aesthetasc ya.
An2 with long and slender Y aesthetasc nearly reaching to end of third segment. Claw G2 just over half-length of claw G 1 in females. G1 claw one-third length of G 2 in males. Male seta t3 three-quarters of length of t2; both thickened with blunt point. Claw Gm approximately three-quarters length of GM.
Md palp second segment with 3+1+beta setae.
carapace, right lateral view (LBM 1430003281). (G–J) Fabaeformiscandona paterea sp. nov. (G) Male, whole carapace, right lateral view (LBM 1430003285); (H) female, whole carapace, right lateral view (LBM 1430003286); (I) dorsal view of left valve (LBM 1430003286); (J) dorsal view of right valve (LBM 1430003286). (K–M) Fabaeformiscandona okuboi sp. nov. (K) Male, whole carapace, right lateral view (LBM 1430003289); (L) female, whole carapace, right lateral view (LBM 1430003294); (M) dorsal view of female, anterior to right (LBM 1430003290). Scale bar below M represents 633 Mm for A and B, 574 Mm for C and D, 619 Mm for E and F, 594 Mm for G–J and 472 Mm for K–M.
L 5 male palps very large and asymmetrical. Right palp with inflated, bulbous head narrowing to point anteriorly. Left palp more hook shaped and more slender anteriorly than right palp, with notch on distal edge.
L6 with five segments, first segment with relatively long d1 seta. Seta e of second segment and seta f of third segment equal in length. Seta g of fourth segment long. Claw of final segment slender, h1 seta approximately four times length of h3 seta.
L7 five-segmented, first segment with dp seta longer than d1 seta. Fourth segment with long g seta. Final segment quadrate with h2 and h3 setae sub-equal in length, h1 just over half-length of h3.
UR slightly curved, claw Gp three-quarters length of Ga, seta Sp short, slightly longer than Sa.
Hp large and elongate, main body rounded distally. Lobe a with straight inner edge, strongly rounded outer edge, both margins meeting at blunt point. Outer edge of lobe with striations running sub-parallel with outer edge. m process robust, terminating with inflated, rounded bulge. Lobe h small and indistinct.
FRO with large, plate-like posterior protrusion, narrow proximally, widening distally. Anterior margin with blunt angle, posterior margin rounded.
Remarks
The distinctive angular posterior margin of this species sets it apart from all other Fabaeformiscandona species from Lake Biwa and elsewhere. The FRO protrusion is also distinctive in its inflated size and shape. This species was found on mud, sand and coarse, poorly sorted substrates at depths ranging from 9.6 to 36.5 m towards the south of the northern basin. Localities 35, 37 and 69 in Figure 1 View Figure 1 .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.