Terrestricythere elisabethae, Horne & Smith & Whittaker & Murray, 2004

Horne, David J., Smith, Robin J., Whittaker, John E. & Murray, John W., 2004, The first British record and a new species of the superfamily Terrestricytheroidea (Crustacea, Ostracoda): morphology, ontogeny, lifestyle and phylogeny, Zoological Journal of the Linnean Society 142 (2), pp. 253-288 : 263-271

T. elisabethae sp. nov.

An2: five podomeres, coxa large and broad ( Fig. 8 ). Basis wider than long. Exopodite plate with one broad, rounded, short seta. 1st endopodite podomere with two short, lobe-like setae on posterior edge; 2nd with one short and one longer lobe-like posterior-apical setae. Final podomere with four rounded, lobe-like setae, two larger of which are hooked.

Md: segmentation indistinct ( Fig. 8 ). Lobe on inner edge incipient coxa (?). Palp with two lobes on inner edge and terminates with three small lobes.

Lobe X: lobe anterior to Fu; elongate and hook shaped ( Fig. 8 ).

Fu: rami triangular in shape, broad base, slightly curved distally ( Fig. 8 ).

Ab: lobe at posterior of body, with rounded end ( Fig. 8 ).

Instar A-7

Carapace: length 152–160 Mm, height 96–100 Mm. Calcified ( Fig. 2). Lateral view rounded, with LV overlapping RV. Anterior slightly more rounded than posterior. Maximum height approximately at mid-length. Dorsal margin strongly curved, ventral margin straight. RV with list. Carapace surface smooth. Each valve with nine pore systems ( Fig. 4 ).

An1: all setae more robust, and longer than in previous instar ( Fig. 8 ). 2nd podomere with additional apical seta. 5th podomere with three apical setae and one apical aesthetasc.

An2: exopodite now with one long seta with hooked end, one short seta and one small lobe ( Fig. 8 ). Basis with additional one small mid-positioned seta. 2nd endopodite podomere with one posterior-apical claw and one aesthetasc. Final podomere with three stout claws and one bent aesthetasc.

Md: coxa with four teeth and one subapical seta on outer edge ( Fig. 8 ). Exopodite consisting of one long seta. 1st endopodite podomere with three apical setae on inner corner; 2nd with one apical claw and one apical seta on inner corner; 3rd with three claws.

Mx: Anlage consisting of rounded lobe, directly behind Md ( Fig. 8 ).

Fu: rami short, stout and rounded, with many setules on posterior edge ( Fig. 8 ), terminating with two short, stout claws and one long claw with thin seta protruding from distal half; seta longer than claw.

Ab: directly posterior of Fu, consisting of stout setulous end ( Fig. 8 ).

Instar A-6

Carapace: length 170–190 Mm, height 105–130 Mm. Carapace shape similar to that of previous instar ( Fig. 2). Each valve with 18 pore systems ( Fig. 4 ).

An1: 2nd podomere with additional small, stout seta on dorsal-apical corner ( Fig. 9 ). 4th podomere with additional apical claw and seta.

An2: coxa with additional seta on posterior edge ( Fig. 9 ). Exopodite with one additional long, hooked seta. 1st endopodite podomere with two additional aesthetascs on posterior edge; 2nd with one additional claw on anterior-apical corner.

Md: coxa with additional tooth ( Fig. 9 ). 2nd endopodite podomere with additional seta on outer-apical corner.

Mx: transformed from Anlage to feeding appendage; palp simple, not segmented, terminating in one stout, curved claw ( Fig. 9 ). 3rd endite terminates with one stout seta, 2nd with three, 1st with two. Branchial plate formed (number of setae unknown as folded in all specimens).

Fu: each ramus with additional long claw, similar to pre-existing long claw, with thin seta protruding from distal half ( Fig. 9 ).

Instar A-5

Carapace: length 205–220 Mm, height 128–144 Mm. Overall shape similar to previous instar ( Fig. 2). Each valve with 35 pore systems ( Fig. 4 ).

An1: similar to that of previous instar ( Fig. 10 ).

An2: 1st endopodite podomere with one additional aesthetasc, now forming group of three ( Fig. 10 ). Exopodite with additional long, hooked seta, forming group of three long setae, one short seta and one small lobe.

Md: additional seta protruding from inner edge of basis ( Fig. 10 ).

Mx: endopodite segmented; 1st podomere with one stout, curved seta on apical-outer edge ( Fig. 10 ). 2nd podomere with additional stout apical seta, forming group of two. Endites with numerous apical setae (number unknown).

L5: Anlage; rounded elongate lobe, tapering distally to point ( Fig. 10 ).

Fu: similar to that of previous instar ( Fig. 10 ).

Instar A-4

Carapace: length 235–260 Mm, height 152–163 Mm. Overall shape similar to previous instar ( Fig. 2). Each valve with 47–50 pore systems ( Fig. 4 ).

An1: 2nd podomere with additional long seta on ventral edge; 4th with additional apical short seta, forming group of five ( Fig. 11 ).

An2: coxa with additional seta on anterior edge ( Fig. 11 ). Exopodite with four long setae. 2nd endopodite podomere with new aesthetasc on posterior edge and small claw on anterior-apical corner; 3rd with four stout claws.

Md: endopodite with two new setae on inner edge ( Fig. 11 ).

Mx: endopodite with one new apical seta on 1st podomere and new apical seta on final podomere. Additional large, broad, setulous seta near base of 2nd endite ( Fig. 11 ).

L5: transformed from Anlage; four podomeres, 1st podomere (protopodite) robust and broad, tapering distally, with three small, stout, anterior-apical claws and long seta (exopodite) on posterior edge. 2nd podomere elongate; 3rd quadrate with small anteriorapical spine; 4th trapezoid with one small seta on posterior edge, one small apical claw and one long apical claw ( Fig. 11 ).

L6: Anlage; rounded elongate lobe, tapering distally to point ( Fig. 11 ).

Fu: each ramus reduced to two small spines and one long claw ( Fig. 11 ).

Instar A-3

Carapace: length 287–300 Mm, height 178–185 Mm. Overall shape similar to previous instar ( Fig. 2). Each valve with 55–59 pore systems ( Fig. 4 ).

An1: 2nd podomere with extra seta on ventral edge next to existing long seta ( Fig. 12 ). 4th podomere with two new setae at mid-point of dorsal edge.

An2: basis with additional seta on anterior-apical corner ( Fig. 12 ). Exopodite with one new, long, seta producing group of five long and one short setae. 2nd endopodite podomere with additional, small, stout claw on posterior edge and small stout claw on anterior-apical corner.

Md: endopodite with extra seta on outer-apical corner of 2nd podomere ( Fig. 12 ).

Mx: endopodite with new seta on outer edge of 1st podomere ( Fig. 12 ).

L5: 3rd podomere with additional small spine on anterior-apical corner ( Fig. 13 ).

L6: transformed from Anlage ( Fig. 13 ). 1st podomere large and robust with one seta on anterior-apical corner; 2nd elongate; 3rd elongate with small, stout claw on anterior-apical corner; 4th small and trapezoid, with small seta on posterior edge and one long claw and one shorter claw apically.

L7: Anlage; rounded elongate lobe, tapering distally to point ( Fig. 13 ).

Fu: Each ramus reduced further to two small, setulous claws ( Fig. 13 ).

Instar A-2

Carapace: length 343–360 Mm, height 218–230 Mm. Overall shape similar to previous instar ( Fig. 2). Each valve with 71–80 pore systems ( Fig. 4 ).

An1: 3rd podomere with additional apical seta; 4th with extra seta along dorsal edge and additional seta on ventral-apical corner ( Fig. 14 ).

An2: exopodite with additional long seta ( Fig. 14 ).

Md: basis with two extra setae on inner edge ( Fig. 14 ). 1st endopodite podomere with one additional seta on inner edge and two new setae on outer edge.

Mx: 1st endopodite podomere with extra seta on outer-apical edge ( Fig. 15 ).

L5: protopodite with additional stout seta on anteriorapical corner and additional long, subapical seta ( Fig. 15 ).

L6: now with five podomeres as result of 3rd podomere in previous instar dividing into two ( Fig. 15 ). Protopodite with additional long seta (exopodite) on posterior edge. 2nd podomere with new spine on anterior-apical corner. 3rd podomere wider than long and with robust spine on anterior-apical corner. 4th podomere wider than long and with robust spine and three smaller spines on anterior-apical corner. Final podomere similar to that of final podomere in previous instar.

L7: Transformed into appendage with four podomeres ( Fig. 15 ). 1st podomere elongate, with two small, stout, anterior-apical setae; 2nd and 3rd elongate; 4th small, trapezoid, with one short, curved claw and one long, curved claw.

Fu: Similar to previous instar ( Fig. 15 ).

Instar A-1

Carapace: Length 413–426 Mm, height 265–265 Mm. Overall shape similar to previous instar ( Fig. 2). Each valve with 99–106 pore systems ( Fig. 4 ).

An1: 3rd podomere with two additional, stout apical setae, producing group of four; 4th with one extra,

stout setae in mid-length position producing group of four ( Fig. 16 ).

An2: Exopodite with additional long seta, producing group of seven long and one short setae. 1st endopodite podomere with one new, small claw on posterior-apical corner; 2nd with one additional claw on posterior edge and one new anterior-apical claw ( Fig. 16 ).

Md: 2nd podomere of endopodite with additional small, apical seta on inner edge ( Fig. 16 ).

Mx: similar to that of previous instar ( Fig. 16 ).

L5: 3rd podomere with additional small, anteriorapical spine ( Fig. 17 ).

L6: 1st podomere with two additional setae on anterior edge, and one new anterior-apical seta ( Fig. 17 ).

L7: now with five podomeres with 3rd podomere in previous instar dividing. 1st podomere with additional small seta on anterior edge ( Fig. 17 ).

Fu: similar to that of previous instar ( Fig. 17 ).

Instar adult

Carapace: length 480–500 Mm, height 322–340 Mm. Dorsal margin slightly more inflated than in previous instar. Each valve with 142–153 pore systems ( Fig. 4 ).

An1, An2, Md and Mx: similar to that of previous instar ( Fig. 5 ).

L5: male L5 with two long and three short stout setae on anterior edge ( Fig. 6 ). 4th podomere used with large terminal hook. Female L5 similar to that of previous instar ( Fig. 6 ).

L6: 2nd, 3rd and 4th podomeres each with one additional small, anterior-apical spine ( Fig. 6 ).

L7: more elongate than in previous instar ( Fig. 6 ).

Fu: in males fused with base of hemipenes ( Fig. 6 ). Similar to previous instar in females ( Fig. 6 ).

Hem: fully developed ( Fig. 6 ).

Remarks on ontogeny

The appearance of limbs through ontogeny of Terrestricythere elisabethae sp. nov. is generally similar to that of other podocopid superfamilies, such as the Cypridoidea , Cytheroidea and Bairdioidea ( Fig. 20 ). The first instar (A-8) of the Cypridoidea , Cytheroidea and Terrestricytheroidea consists of the antennulae, antennae and the Anlagen of the mandibles ( Fig. 21 )

Figures

Figure 4. Terrestricythere elisabethae sp. nov. Maximum number and position of pore systems on left valves of instars.

Figure 5. Terrestricythere elisabethae sp. nov. Adult instar. An1 (2003.1024 female), An2 (2003.1023 female, 2003.1025 male), Md (2003.1024 female), detail of rake seta (2003.1027 male), Mx (2003.1025 male).

Figure 6. Terrestricythere elisabethae sp. nov. Adult instar. L5 (2003.1026 male), L5 (2003.1024 female), L6 (2003.1025 male), L7 (2003.1025 male), female genital lobe (2003.1023 female), Hem (2003.1025 male).

Figure 8. Terrestricythere elisabethae sp. nov. A-8 instar (2003.1029). A-7 instar; reconstruction of body plan based on 2003.1033. An1 (2003.1032), An2 (2003.1030), Md (2003.1030), Mx (2003.1030), Fu (2003.1031).

Figure 9. Terrestricythere elisabethae sp. nov. A-6 instar (2003.1034).

Figure 10. Terrestricythere elisabethae sp. nov. A-5 instar. An1 (2003.1035), An2 (2003.1035), Md (2003.1037), Mx (2003.1037), L5 (2003.1037), Fu (2003.1036).

Figure 11. Terrestricythere elisabethae sp. nov. A-4 instar. An1 (2003.1039), An2 (2003.1039), Md (2003.1039), Mx (2003.1038), L5(2003.1039), L6 (2003.1038), Fu (2003.1038).

Figure 12. Terrestricythere elisabethae sp. nov. A-3 instar. An1 (2003.1042), An2 (2003.1043), Md (2003.1044), Mx (2003.1044).

Figure 13. Terrestricythere elisabethae sp. nov. A-3 instar. L5 (2003.1042), L6 (2003.1040), L7 (2003.1041), Fu (2003.1041).

Figure 14. Terrestricythere elisabethae sp. nov. A-2 instar. An1 (2003.1045), An2 (2003.1045), Md (2003.1046).

Figure 15. Terrestricythere elisabethae sp. nov. A-2 instar. Mx (2003.1046), L5 (2003.1047), L6(2003.1045), L7(2003.1046), Fu (2003.1046).

Figure 16. Terrestricythere elisabethae sp. nov. A-1 instar. An1 (2003.1048), An2 (2003.1048), Md (2003.1048), Mx (2003.1048).

Figure 17. Terrestricythere elisabethae sp. nov. A-1 instar. L5 (2003.1048), L6(2003.1048), L7(2003.1048), Fu (2003.1048).

Figure 20. Summary of the appearance of limbs during ontogeny of Terrestricythere elisabethae sp. nov. and three representative species of the superfamilies Bairdioidea, Cypridoidea and Cytheroidea. Neonesidea oligodentata taken from Smith & Kamiya (2002), Loxoconcha japonica taken from Smith & Kamiya (2003), Eucypris virens taken from Smith & Martens (2000).

Figure 21. The A-8 instars of Terrestricythere elisabethae sp. nov. and two representative species of Cytheroidea and Cypridoidea. Heterocypris bogotensis taken from Roessler (1983), Loxoconcha japonica taken from Smith & Kamiya (2003).