Ufocandona hannaleeae, Külköylüoğlu & Yavuzatmaca & Akdemir & Schwartz & Hutchins, 2017

Külköylüoğlu, Okan, Yavuzatmaca, Mehmet, Akdemir, Derya, Schwartz, Benjamin F. & Hutchins, Benjamin T., 2017, Ufocandona hannaleeae gen. et sp. nov. (Crustacea, Ostracoda) from an artesian well in Texas, USA, European Journal of Taxonomy 372, pp. 1-18 : 7-12

Ufocandona hannaleeae gen. et sp. nov.

urn:lsid:zoobank.org:act:5CF0A5FB-F64F-45B5-837E-1BBCAB741D03

Figs 2–7

Diagnosis

The species diagnosis is identical to that of the genus.

Etymology

The species name hannaleeae is in honor of Hanna Lee Sanborn, who is a steward of the San Marcos River and the Edwards Aquifer. The naming rights for this species were donated to the San Marcos River Foundation (SMRF) by the authors, as a fundraising item. Naming rights were purchased for Hanna Lee Sanborn by her fiancé, Matthew Erickson, at the 2016 SMRF annual meeting and silent auction, in honor of their engagement. All proceeds from the naming rights auction directly benefitted SMRF, a 501c3 non-profit organization whose mission is to “preserve and protect the natural beauty, flow, and purity of the San Marcos River”, which is a spring-fed river derived from the Edwards Aquifer.

Material examined

Holotype

UNITED STATES OF AMERICA: ♂, Texas, Hays County, San Marcos artesian well (SMAW), 29°53′22.46′′ N, 97°56′11.27′′ E, 19 Nov. 2013, Benjamin F. Schwartz and Benjamin T. Hutchins leg. ( OK-TX-AW049-01 ), all soft body parts dissected in lactophenol solution and sealed with translucent nail polish, valves in micropaleontological cavity slide (OK-TX-AW049-03).

Allotype

UNITED STATES OF AMERICA: ♀, collection data as for holotype (OK-TX-AW049-02), all soft body parts dissected in lactophenol solution and sealed with translucent nail polish, valves in micropaleontological cavity slide (OK-TX-AW051-04).

Paratypes

UNITED STATES OF AMERICA: 1 ♂ (OK-TX-AW049-05), 2 ♀♀ (OK-TX-AW051-06), collection data as for holotype.

Other material

UNITED STATES OF AMERICA: 6 ♀♀, 4 ♂♂, 3 juv., collection data as for holotype, in 70% ethanol, deposited at the Limnology Laboratory, Department of Biology, Abant İzzet Baysal University, Bolu, Turkey.

Description

Male

MEASUREMENTS. Holotype: L(LV)= 0.442 mm, L(RV) = 0.427 mm, H(LV)= 0.344 mm, H(RV) = 0.312 mm.

VALVES. LV overlaps RV from all sides ( Fig. 2B ). In lateral view, RV almost subtriangular in shape, with normal pore openings ( Figs 2B, F , 3B ). Dorsal margin of RV flat, sloping posteriorly. Both margins rounded, anterior margin more broadened than posterior. Greatest height located almost in middle of LV but located anteriorly on RV. Only LV with enlarged prolongation (flange) dorsally (diagnostic character). Valve surface mostly smooth at center but ornamented with hexagonal structures around marginal zones. Marginal zones of RV with dense tiny spines ( Fig. 2C ). Shallow pits and fine setae present in both sexes and juveniles. Central muscle scars not visible in external view ( Fig. 2 A–D) but visible in interior view ( Fig. 3 A–B). Hinge adont. Color translucent to opaque white. Eyes not observed or eye pigment absent. Viewed internally, anterior and posterior marginal areas of LV with 5–6 and 3–4 round tubercles on first list, respectively (diagnostic character). Second list shorter than first one. Calcified inner lamella almost equally wide at both ends, uncalcified inner lamella wide. In dorsal view, both ends thin and beakshaped, carapace laterally tumid, valves slightly concave ventrally ( Figs 3A , 7B ).

A1 ( Fig. 4A ). 8-segmented. First segment with one long, smooth apical seta on dorsal side of A1, reaching to end of second segment. Second segment with one medium-sized, smooth antero-distal seta at mid-length on dorsal side of segment, about half length of second segment. Rome organ absent. Wouters organ not seen. Third segment with small, apical (spine-type) seta on dorsal side. Fourth and sixth segments without setae. Fifth segment with two short (ca ¼ of segment) anterior and posterior setae. Penultimate (seventh) segment with two very long antero-distal setae, approximately equal in length to all eight segments. Terminal segment with two equally long setae and one slightly shorter aesthetasc ya.

A2 ( Fig. 4B ). 4-segmented. Exopod with two very short setae (compare with female). First segment with long ventro-apical seta, approximately length of next three segments. Second segment with 2-segmented, long medio-ventral aesthetasc Y and one long seta, both of about same size and extending almost half length of terminal claws. t-setae absent. Third segment distally with three apically slightly plumose (G1), smooth (G2) or serrated (G3) claws; G2 claw slightly shorter than G1 and G3 claws, three z-setae (z1 and z3 short, z2 claw-like, almost reaching half of G2 claw) present, y1–y2 aesthetascs not seen. Terminal (fourth) segment with one long GM claw, about length of G3 claw, and one short Gm claw (⅓ length of GM). Both claws smooth. Aesthetasc y3 not seen. Compare with A 2 in female ( Fig. 4C ).

RAKE- LIKE ORGAN. Reduced, not seen well.

MD ( Fig. 5A ). Coxa well developed, with 8–9 spine-like teeth and 3 setae. Md-palp 4-segmented, without alpha, beta or gamma setae (diagnostic character). First segment with two medio-internal, long smooth setae about same length as segment. S1 and S2 setae smooth. Vibratory plate with about 7–8 setae, not seen well. Second segment anteriorly with 3+1 setae, almost equal in size. Third (penultimate) segment ventro-apically with one well-developed, smooth, claw-like seta and a short seta. Terminal segment fused with terminal claw, carrying two well developed and slightly plumose claws.

MXL ( Fig. 5B ). Mxl-palp two segmented. First palp with smooth seta located ventro-apically. Terminal segment of Mxl palp very short, with two (one long and one short) smooth setae. Apical corner of first palp segment with two sharp, spine-like setae, slightly longer than other setae of terminal segment. Vibratory plate with about 14 slightly plumose filaments. Three lobes (endites), normal in shape, ending with 3, 4 and 4 smooth setae on first, second and third lobes, respectively. Base of first lobe with long seta extending to terminal palp.

T1 ( Fig. 5 C–D). Prehensile palp not segmented, both similar in size and modified into clasping organs, 3× as long as masticatory process. Anteriorly, palps ending with upper and lower parts. Upper part long, strongly curved anteriorly, ending with triangular apical part. Lower part thin and short, ending with short, tooth-shaped piece. One long b seta of about same length as masticatory part, other setae (a, c, d setae) absent. Masticatory process short, distally with 6 setae, 2× as long as masticatory part (see also Fig. 6D for female T1). Respiratory plate reduced to one tiny filament.

T2 ( Fig. 5E ). Five-segmented, with only one well-developed d1 seta on first segment (protopodite). Second, third and penultimate segments with one smooth, sub-apical (e, f, g) seta, anteriorly. Terminal segment with one very long, smooth claw (h2), extending to about end of second segment, and one very short h3 seta. Seta h1 missing.

T3 ( Fig. 4D ). 4 segmented with one medium size seta (d1) on the first segment (protopodite). Second segment long, about size of penultimate and terminal segments combined. Penultimate segment undivided ( Fig. 3A ), four groups of setules present dorsally (note: not seen internally; Fig. 3B ). Three setae (e, f, and g) absent on segments 2–3. Terminal segment short, with three well-developed setae (h1–3). h3 slightly longer than h1. Seta h2 slightly curved and short, about half length of h3. Two long setae (h1 and h3) extending to second segment.

UROPOD. With thin, spine-like terminal seta, similar to flagellum-type uropod in subfamily Cypridopsinae , with thin, approximately cylindrical ramus.

HEMIPENIS ( Fig. 6B ). Lobe a with triangular end, lobe b with broad end, lobe h rounded (diagnostic character). M-process large, with distal part (g) strongly curved.

ZENKER ORGAN ( Fig. 6C ). With 4+2 rings of spines, ending with sperm canal.

Female

Carapace similar in shape and size to that of male ( Fig. 2A, E , 7 A–B). Female (allotype): L= 0.56 mm, H = 0.38 mm. Average: L= 0.473 mm (n =3), H = 0.364 mm (n=3), W= 0.245 mm (n=2). T1 normally developed, with three h1–3 setae ( Fig. 6D ). Setae h1 and h3 almost equal in size and slightly shorter than h2. Exopod and exopodial setae on A2 not observed. All G claws (G1–G3, GM, Gm) present ( Fig. 4C ). z1–3 setae very small. Genital part very small, rounded and without genital process ( Fig. 6A ). One or two small, white to yellowish eggs visible in external view of carapace. All other soft parts similar to those of male.

Ecology

Ufocandona hannaleeae gen. et sp. nov. is known only from the type locality, where it occurs with 23 additional stygobionts, including a plethodontid salamander, two species of isopods, two species of decapods, a thermosbanacean, a planarian, three species of gastropods, a dytiscid beetle, a cyclopoid copepod, a hirudinean, and ten species of amphipods ( Hutchins et al. 2014, 2016). However, the stygobiont fauna from this locality is incompletely known and also includes additional ostracod species, additional cyclopoid and harpacticoid copepods, aquatic mites, a bathynellid, and additional isopods and amphipods (Külköylüoğlu, Hutchins and Schwartz, pers. obs.), making the San Marcos artesian well one of the most biologically diverse groundwater sites on Earth ( Holsinger & Longley 1980; Culver & Pipan 2009). The lack of pigment, relatively thin carapace, reduced eyes and reduction of many setae (see above description) suggest that Ufocandona hannaleeae gen. et sp. nov. is also a stygobiont.

Species at the San Marcos artesian well utilize diverse carbon sources derived in part from chemolithoautotrophic production occurring along a freshwater-saline water interface along the downdip edge of the Edwards Aquifer ( Hutchins et al. 2016). Primary productivity has played an important role in the evolution and maintenance of the longest subterranean food chain currently known ( Hutchins & Schwartz 2013), and species partition food resources ( Hutchins et al. 2014, 2016). Furthermore, invertebrate species from the San Marcos artesian well display a diversity of body morphologies, and the relative abundance of species varies substantially in response to precipitation (Hutchins and Schwartz, pers. obs.). These suggest a heterogeneous environment comprised of a mosaic of microhabitats. However, there is currently no detailed information about habitat preference or trophic ecology for Ufocandona hannaleeae gen. et sp. nov. Because species of the subfamily are not able to swim, due to the absence of swimming setae on A2, Ufocandona hannaleeae gen. et sp. nov. is probably an obligate benthic species inhabiting sediments, rock surfaces or biofilms. Of the nearly 12 000 ostracods collected from this site, less than 20 belong to Ufocandona hannaleeae gen. et sp. nov. This may be due to relative rarity or, because it does not swim, the species may only rarely be expelled from the well. The remaining individuals are the subject of ongoing study and results will be presented elsewhere.

Distribution

Known only from the type locality.

Figures

Fig. 2. Ufocandona hannaleeae gen. et sp. nov. A. LV of ♀, external view. B. RV of ♂, external view. C. Posterior end of RV with spines in ♂. D. Anterior end of RV in ♂ (note broken part). E. LV of ♀ with tubercles, internal view (note broken part in the center). F. RV of ♂, internal view. Arrows indicate anterior end. Scale bars: A–B, E–F =100 µm; C–D =20 µm.

Fig. 3. Ufocandona hannaleeae gen. et sp. nov. A. Dorsal view of ♂ (arrow indicates anterior end). B. Normal pore opening with sensory seta. C. Soft body parts of ♂. D. Rear end of body, ♂; the thin arrow points to the four tiny setal groups on T3, the thick arrow to the distal end of T3. E. Ends of adductor muscles. Scale bars: A=100 µm; B=20 µm; C–E =10 µm.

Fig. 4. Ufocandona hannaleeae gen. et sp. nov. A. A1, ♂. B. A2, ♂. C. A2, ♀. D. T3, ♂. Scale bars = 25 µm.

Fig. 5. Ufocandona hannaleeae gen. et sp. nov, ♂. A. Md. B. Mxl. C–D. Left and right T1. E. T2. Scale bar: A–C, E =25 µm; D =10 µm.

Fig. 6. Ufocandona hannaleeae gen. et sp. nov. A. Ur with female genital organ. B. Hemipenis. C. Zenker’s organ. D. T1. A, D: ♀; B, C: ♂. Scalebar =10 µm.

Fig. 7. Ufocandona hannaleeae gen. et sp. nov., ♀. A. External view of carapace from right side (note the dorsal flange on LV). B. Carapace in dorsal view. Both in transmitted light. Not to scale.