Corresponding author: Saskia Brix (
Academic editor: O. Moldovan
Bruce NL, Brix S, Balfour N, Kihara TC, Weigand AM, Mehterian S, Iliffe TM (2017) A new genus for
During the last decades, it has become increasingly obvious that species diversity in caves has only been marginally captured and that many aquatic cave species still remain to be discovered and described (
The isopod family
The shallow water habitats of the Bahamas have existed over a long geological time scale, at least the constitutive limestone persisted over the last 120 MA (Jaume et al. 2013). Combined with tectonic fracturing, extensive karstification produced a vast network of voids within the 4448 m thick limestone (Mylroie and Carew 1995). As shown on the map in Holsinger et al. (2007, figure 3 p. 1050), the Bahamas have accumulated many subterranean cirolanid isopods. The collection of a series of cirolanids from Hatchet Bay Cave, Eleuthera, identified as
All specimens were sampled from the main hall and the western chamber of Hatchet Bay Cave using six miniature minnow traps (Figures
Hatchet Bay Cave Main Gallery, Eleuthera, The Bahamas (Photograph).
Classification follows
Photographs of female (CC-1:
Species descriptions were prepared in DELTA (Descriptive Language for Taxonomy, see:
Comparison of generic characters between
Character |
|
|
---|---|---|
Frontal lamina – size | Extends to antenna bases | Does not extend beyond antennula bases |
Frontal lamina – size | Wide, c. 40% width of clypeus | Less than 10% width of clypeus |
Frontal lamina – shape | Pentagonal or sub-quadrate – 4 or 5 margins | Linear, three margins |
Pleonite 1 dorsal | Scarcely or not visible | Visible |
Pleonite 1 ventral | Not visibly present | Visibly present with ventral structure |
Pleonite 3 | Without ventral blade | With large ventral blade |
Antennula | Peduncle articles 1 and 2 combined lengths greater than article 3 length | Peduncle articles 1 and 2 combined lengths less than article 3 length |
Pereopod 1 merus | With tubercular robust setae | With acute robust setae |
Two adult specimens of
Various lenses were used, depending on the size of the material scanned (Table
List of figures with information on microscope lenses and confocal laser scanning microscopy (
Figure | Objective/ Numerical aperture | Detected emission wavelength (nm) | Detector gain (V)/ Amplitude offset (%) | Electronic zoom | Pinhole aperture (µm) |
---|---|---|---|---|---|
Figs |
2.5X/0.07 | Ch1: 570–629 |
Ch 1: 667.0/ -1.7 |
1.0X | 75.7 |
Fig. |
2.5X/0.07 | Ch1: 570–629 |
Ch 1: 667.0/ -1.7 |
1.8X | 75.8 |
Fig. |
10X/0.4 | Ch1: 570–622 |
Ch 1: 593.0/ -1.7 |
1.0X | 53.0 |
Fig. |
10X/0.4 | Ch1: 570–629 |
Ch 1: 554.0/ -1.7 |
1.0X | 53.0 |
Fig. |
40X/0.75 | Ch1: 570–629 |
Ch 1: 630.0/ -1.7 |
1.0X | 113.2 |
Fig. |
10X/0.4 | Ch1: 570–629 |
Ch 1: 542.0/ -1.7 |
1.0X | 53.0 |
Fig. |
10X/0.4 | Ch1: 570–629 |
Ch 1: 536.0/ -1.7 |
1.0X | 53.0 |
Fig. |
10X/0.4 | Ch1: 570–629 |
Ch 1: 550.0/ -1.7 |
1.6X | 53.0 |
Fig. |
40X/0.75 | Ch1: 570–629 |
Ch 1: 585.0/ -1.7 |
1.0X | 113.2 |
Figs |
10X/0.4 | Ch1: 570–622 |
Ch 1: 560.0/ -1.7 |
1.0X | 53.0 |
Fig. |
40X/0.75 | Ch1: 570–629 |
Ch 1: 488.0/ -1.7 |
1.0X | 53.0 |
Fig. |
40X/0.75 | Ch1: 570–629 |
Ch 1: 572.0/ -1.7 |
1.0X | 113.2 |
DNA extraction was performed as outlined by
Specimens of
GENBANK NUMBER PER SEQUENCE | ||||||||
---|---|---|---|---|---|---|---|---|
field ID | Museum number | sex | extract ID | 16S |
|
18S |
|
SEM |
CC-1 | female | KJ330 | – | |||||
CC-2 | male | KJ331 |
|
× | ||||
CC-3 | female | KJ332 | – | – | – | |||
CC-4 | female | KJ333 |
|
|||||
CC-A-14 | female | – | – | – | – | × | ||
CC-B-14 | female | – | – | – | – | × | ||
CC-A-16 | female | – | – | – | – | × | ||
CC-B-16 | female | – | – | – | – | × | ||
CC-5-16 | female | – | – | – | – | × | ||
CC-6-14 | female | – | – | – | – | × | ||
CC-7-16 | female | KJ334 | – | |||||
CC-8-16 | female | KJ335 |
|
|||||
CC-9-16 | female | KJ336 | – | – | ||||
CC-10-16 | female | KJ337 | – | |||||
CC-11-14 | female | KJ338 | – | |||||
CC-12-14 | female | KJ339 | – | |||||
CC-13-14 | female | KJ340 | – | |||||
CC-14-14 | female | KJ341 | – | |||||
CC-15-14 | female | KJ342 | – | |||||
CC-16-14 | female | KJ343 | – | |||||
CC-17-16 | female | KJ344 | – | |||||
CC-18-16 | female | KJ345 | – | |||||
out of 16: 6 specimens | females | – | – | – | – | |||
out of 14: 5 specimens | females | – | – | – | – | |||
CC-1-4 | female | – | – | – | – | |||
CC-2-4 | female | – | – | – | – | |||
CC-3-4 | female | – | – | – | – | |||
CC-4-4 | female | – | – | – | – |
Abbreviations used on figures:
Head approximately 65% as wide as pereonite 1, anterior margin sub-truncate, rostrum absent. Body surfaces unornamented; pereonite 1 about 1.7 times as long as pereonite 2 in dorsal view. Pleon unornamented, about 16% BL, with 5 visible unfused segments, pleonite 1 partly visible in dorsal view; pleonite 2 posterolateral margin weakly produced; those of pleonite 3 extending to posterior of pleonite 5. Pleotelson without longitudinal carinae, ridges or without tubercles; posterior margin with
Antennula peduncle articles 1 and 2 not fused; peduncular article 2 at right angles to article 1; articles 1 and 2 short, combined length about length of article 3; articles 2 and 3 collinear flagellum 1.4x longer than peduncle; without callynophore. Antenna peduncle comprised of 5 articles, peduncular articles 1–3 shortest, articles 4 and 5 longest, 5 longer than 4; flagellum about twice as long as peduncle.
Frontal lamina short, ventrally flat, lanceolate, not extending to anterior margin of antennal peduncle, posteriorly abutting clypeus. Clypeus ventral surface not projecting relative to frontal lamina. Mandible incisors wide, right incisor tricuspidate; spine row with 4–5
Pereopods 1–7 dactylus with elongate secondary unguis present. Pereopod 1 dactylus shorter than palm; simple
Pleopod 1 rami lamellar; endopod about 0.6 as wide as exopod, 2.4 times as long as wide. Pleopod 2 appendix masculina longer than endopod. Pleopods 1–5 with
To date only one male specimen (described herein) has been collected. Appendix masculina inserted basally, slender; penial processes flat, quadrate, widely separate lobes.
The difference in frontal lamina shape and size between
Pleon morphology is generally consistent within cirolanid genera with regard to a characters such as fusion, extent of the pleonite posterolateral margins, expansion of posterolateral margins and also relative size of the pleon (as a percentage of total body length) and the number of visible somites.
The most similar genus is the monotypic
There are three other genera that are superficially similar to
The monotypic
The name is derived from the Lucayan peoples, the original inhabitants of the Bahamas.
Oven Rock Cave, [Great Guana Cay] Exuma Cays, The Bahamas; habitat is anchialine.
Non-type material: ♀ (non-ovig. 8.5 mm), Great Guana Cay, Exuma Cays, Bahamas; Oven Rock Cave, 31 March 1988, coll. TM Iliffe. (
Also examined.
Similar to female but for sexual characters. Appendix masculina 1.7 times as long as endopod, 17.0 times as along as proximal width, apex with short acuminate tip. Penial processes separated by 20% width of sternite, flat quadrate lobes, width 1.04 length.
Many specimens had the robust setae missing, so precise counts could not be obtained from all specimens. The number of marginal robust setae on the
The range of variation in the robust setae of the uropodal endopod mesial margin is unusual within the family. Also unusual is the difference in the shape of the pleotelson posterior margin, for the most being subtruncate with the uropodal rami extending beyond the posterior margin of the pleotelson (e.g. Figures
The species can be identified by the generic characters, the small and anteriorly acute frontal lamina together with the pleonite morphology, notably the ventral expansion of the lateral margin of pleonite 2, distinguishing the species from all other cave cirolanids in the region. Molecular identification is possible using the species DNA barcodes.
Previous records are from anchialine caves on Great Exuma Island (Oven Rock Cave), Cat Island, Grand Guana Cay (one of the Exuma Cays) and Eleuthera; all are on the Great Bahama Bank, a shallow water platform surrounded on all sides by deep ocean waters.
The mitochondrial
The
The Bahamas archipelago is subdivided into a series of large shallow water platforms, referred to as banks, which had their origins during the initial stages of the formation of the Atlantic Ocean in the Early Cretaceous (
Since the beginning of the Pleistocene, the Bahama banks have been greatly impacted by changing ice age sea levels. The Banks were dry land during past ice ages (
The modern day Bahamian Islands were not formed by coral reefs but instead by the precipitation of ooid sands in the shallows of these large carbonate platforms during high sea stands in the mid to late Quaternary. Ensuing periods of low sea levels exposed these sands to the atmosphere and, blown by wind (eolian deposition), the dune ridges and dry surfaces of the islands took shape (
Hatchet Bay Cave on Eleuthera is one of the largest known flank margin caves in the Bahamas (
Although studies of the anchialine fauna of the Bahamas have been ongoing for more than 30 years, hundreds of caves remain to be investigated and few have been thoroughly surveyed or explored such that numerous species likely remain undiscovered or undescribed. Today, the Bahamas has the richest fauna of stygobiont anchialine crustaceans from any area in the world. In total, 123 crustacean species have been recorded from Bahama’s caves, many to the same genera (e.g.
Specimens of
Hypothetically the different caves may be interconnected by an underground network of cracks and crevices, i.e. the crevicular system as proposed by
Although the majority of Bahama’s anchialine species are endemic and so far known only from a single cave or adjacent caves that are likely connected, several anchialine crustaceans are more widespread such as the cirolanid isopod
The limestone caves of the Bahamas have likely persisted as habitat over the last 120 MA and the buffered environment may partly explain their unusual accumulation of subterranean taxa (Jaume et al. 2013). During this time period, the populations of
It is of interest that two species of cirolanid,
We thank Karen Jeskulke for her help with the lab work and producing sequence data at the