Halocypridina Dana 1853

Kornicker, Louis S., Iliffe, Thomas M. & Harrison-Nelson, Elizabeth, 2007, Ostracoda (Myodocopa) from Anchialine Caves and Ocean Blue Holes, Zootaxa 1565 (1), pp. 1-151 : 20-24

Suborder Halocypridina Dana 1853

Composition and distribution. The suborder includes the superfamilies Halocypridoidea Dana, 1853 , and Thaumatocypridoidea Müller, 1906 . Both superfamilies are represented in the collections reported upon herein. The distribution of anchialine ostracodes in the suborder Halocypridina in inland and ocean blue holes in the Bahamas is shown in Tables 1 and 2.

Discussion of identification. The following six morphological characters are useful in identifying the taxa and also may reflect relationships among the taxa ( Table 5). A new subfamily, Spelaeoeciinae , is proposed herein, and that subfamily and the subfamily Deeveyinae are placed in the elevated family Deeveyidae in the superfamily Halocypridoidea . The genus Spelaeoecia was formerly placed in the subfamily Deeveyinae .

1. Members of the Thaumatocypridoidea and members of the Deeveyidae , a family in the Halocypridoidea , have two separated rami on the adult male copulatory organ: a broad anterior ramus and a narrower posterior ramus. The male copulatory organs of the adult males of taxa in the Halocypridoidea other than the Deeveyidae have the narrow posterior ramus inserted inside the broad anterior ramus. The A- 1 males of all Halocypridoidea have separated rami. The inserted type is interpreted to be the apomorphic character state. The presence of two separate rami in the copulatory organ of all known extant members of the Thaumatocypridoidea , which have fossil members in the Permian, may support that conclusion ( Fig. 9 ).

2. The sixth limbs of the Thaumatocypridoidea and members of the genera Deeveya and Spelaeoecia in the family Deeveyidae in the Halocypridoidea have an exopod represented by a lobe bearing bristles. The lobe is absent on members of the Halocyprididae . The lobe is interpreted herein to be the plesiomorphic character state, and the absence of a lobe the apomorphic character state.

3. The exopod lobe of the sixth limb bears different numbers of bristles: Thaumatocypris one bristle plus one spine, Danielopolina two bristles, Thaumatoconcha three bristles, Deeveya four bristles, Spelaeoecia five bristles. The Halocyprididae do not have a lobe but do have several bristles that could be interpreted to represent an exopod ( Kornicker 2003); these have not been considered in Table 5. The number of exopod bristles for each genus is listed in Table 5, but whether the sequence reflects relationships is not known.

4. The carapaces of the Thaumatocypridoidea are without an incisure. In the Halocypridoidea , the carapaces of members of the genus Deeveya in the Deeveyidae have an incisure represented, at most, by a very slight anterior concavity. The carapaces of members of the genus Spelaeoecia , also in the Deeveyidae , and most species of the Halocyprididae have a well defined incisure. A well-defined incisure is interpreted herein as the apomorphic character state ( Fig. 9 ).

5. The carapaces of the Thaumatocypridoidea are without the marginal glandular openings present in the carapaces of members of the Halocypridoidea . The presence of marginal glandular openings is tentatively interpreted herein as the apomorphic character state, mainly because they do not appear to be present in fossil carapaces.

6. The basis of the mandible of all known species of Deeveya and two species of Spelaeoecia , both members of the Deeveyidae , has two entwined lateral bristles ( Fig. 28c, g ). The corresponding bristles are not entwined on other known members of the Halocypridoidea . The entwined form is interpreted herein to be the apomorphic character state.

Discussion of mandible. The basis of mandibles of adults and late instars of known species of Deeveya and also two species of Spelaeoecia has two entwined bristles ( Table 6; Fig. 28 c, g ) ( Kornicker & Iliffe 1998: figs. 7e, 13c,d). Although the data are few on early instars, both bristles are absent on the A-5 instar, only one of the bristles is present on the A-4 and A-3 instars, and both bristles are present in later stages ( Table 6). In species of Deeveya the bristles cross two or three times on the A-2 instar and five times on the A-1 instar and on both the adult female and male ( Table 6; Fig. 28 g ). The two bristles cross each other twice on an A-1 instar as well as on an adult male and female of S. cubensis , and cross each other five times on an adult female S. capax and only three times on an adult male. The absence of entwined bristles on thaumatocyprids suggests that the entwining of the bristles in Deeveya represents a synapomorphic character state. The entwining in the two species of Spelaeoecia is tentatively interpreted as convergence. The function, if any, of the entwined bristles is unknown. Of possible significance is that in the entwined state the bristles are shorter than if they were not entwined. In an enquiry among a few crustacean specialists ( Decapoda, Isopoda , Copepoda), none could recall having observed species with entwined bristles.

*The six morphological characters are discussed in "Discussion of Identification" (p. 21 herein)

Figures

FIGURE 9. Possible evolutionary sequence of Halocypridina based on whether male copulatory organ has separate or inserted rami and carapace shape.

FIGURE 28. Deeveya bransoni Kornicker & Palmer 1987, USNM 1021408, adult male: mandible: a, upper lip with right mandible in place; b, proximal tip of left coxa and ends of adjacent central adductor muscles projecting from left side of body, anterior to left, lv. Right mandible: c–e, limb drawn attached to body, lv (nabs); f, tip of coxa, lv; g, basis, lv; h,i, endopod, mv. Left mandible: j, basis and exopod, mv (nabs). Scale equals 0.10 mm (a,b,d,e,g,j), 0. 20 mm (c), and 0.05 mm (f,h,i).