Research Article |
Corresponding author: Marc A. Milne ( milnem@uindy.edu ) Academic editor: Oana Teodora Moldovan
© 2018 Marc A. Milne, Elizabeth Wells.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Milne MA, Wells E (2018) A new species of spider (Araneae, Linyphiidae, Islandiana) from a southern Indiana cave. Subterranean Biology 26: 19-26. https://doi.org/10.3897/subtbiol.26.25605
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The genus Islandiana (Araneae, Linyphiidae) was erected by Braendegaard in 1932 and is comprised of 14 species, most of which are native to North America. Herein we add a 15th species, Islandiana lewisi sp. n., from southern Indiana, USA. This species resembles both I. flavoides Ivie, 1965 and I. cavealis Ivie, 1965, the latter of which is geographically-close.
Erigoninae , Midwest, subterranean, underground, karst, sheet-web spider
The linyphiid genus, Islandiana Braendegaard, 1932 possesses 14 species (
A re-examination of new distribution records listed for the state of Indiana by
All measurements are in millimeters. Measurements were taken electronically using a Leica M165C stereoscope, Leica DMC2900 attached digital camera, and associated Leica Application Suite software (LAS Ver. 4.9.0 [Build: 129], Leica Microsystems, Switzerland) at the University of Indianapolis. Photographs were taken with specimens placed in glass dishes containing white sand and ethanol. Carapace width was measured at the widest part of the carapace. Specimens were prepared for SEM photography by dehydration using ethanol solutions that graduated from 70% to 100% over 5-minute intervals. Specimens were then placed in Hexamethyldisilazane (HMDS; 99+%; Alfa Aesar, Heysham, England) for 5 minutes before being removed and placed on filter paper to dry for 5 minutes. Specimens were then mounted on SEM stubs using 12 mm Pelco Tabs (TED PELLA, Inc. - carbon conductive tabs), sputter coated in gold (Cressington Scientific Instruments, Model No. 108) and photographed using a JEOL JCM-6000 NeoScope benchtop scanning electron microscope. The holotype male and paratypes of females and males were deposited at The Field Museum of Natural History (
Islandiana
cavealis
(Ivie, 1965):
Holotype male and paratype males and females (
Islandiana cavealis: USA: Kentucky: Fayette County, Picadome Cave (N37°, W84°) 1 female (AMNH_IZC 00328222); collected by C. Krekeler and J. Rittmann on 1 July 1957. Islandiana speophila: USA: West Virginia: Pendleton County, Trout Cave (N38°, W79°) 1 female (AMNH_IZC 00328223); collected by L.G. Conrad on 4 March 1961. Islandiana flavoides: USA: New York: Orient (N41°, W72°) 1 male (AMNH_IZC 00328224); collected by C.R. Crosby and S.C. Bishop on 21 June 1934.
The species name is a patronym in honor of our friend and colleague Dr Julian J. Lewis, a cave and karst specialist, a leading expert in North American isopod taxonomy, and the original collector of the species.
This species is most similar to I. flavoides Ivie, 1965, a species native to New York, USA and keys out to this species using the key provided by
Male. (N = 2) Carapace 0.88–0.94 long, 0.69–0.75 wide. Total length 1.90–2.00. Carapace concolorous dusky yellow to tan with a small amount of black surrounding each eye. Five short setae along median line of carapace from fovea leading up to eyes, other setae between posterior median eyes and other eyes leading back to fovea. Abdomen light gray (Fig.
Mature male palp with tibial apophysis rather short and stout (Fig.
Female. (N = 4) Carapace 0.88–1.00 long, 0.69–0.79 wide. Total length 2.1–2.3. Carapace coloration and setae pattern same as male. Abdomen light yellowish to tan (Fig.
Epigynum similar to I. cavealis. Epigynum protruding ventrally at distal portion; conical shape, posterior sclerite wider distally with flattened triangular shape proximally (Figs
Known only from the type locality.
Stygian River Cave is short and consists of a room filled with large, wet, muddy rocks and boulders. Because of the short length of the cave, the biota is likely heavily influenced by low winter humidity. The cave sits at the confluence of the Blue and Ohio rivers and at least part of the cave is regularly underwater when these rivers rise. These specimens were largely found in webs in between the large boulders within the largest room of the cave. The type locality was only visited once and were therefore only collected once, on October 23rd, 2016.
Illustrations of Islandiana lewisi sp. n. structures. A Left palp of male, medial view B Left palp of male, lateral view C Epigynum, ventral view D Epigynum, flipped – dorsal view E Tibial apophysis of left palp of male. E = Embolus; R = radix; SA = suprategular apophysis; ST = subtegulum; T = tegulum; PC = paracymbium; S = spermathecae; PS = posterior sclerite.
SEM micrographs of the left palp of Islandiana lewisi sp. n. A Ventral B Medial C Lateral. E = Embolus; ED = Embolic division; EM = Embolic membrane; MP = medial projection of ED; VP = ventral projection of ED; R = radix of ED; SA = suprategular apophysis; ST = subtegulum; T = tegulum; PC = paracymbium.
We would like to thank Julian J. Lewis for showing us the cave and acquiring permits, Don Buckle for taxonomic help, Nina Sandlin for the counting of stridulae, Chris Schmidt and Kevin Gribbins for SEM help, Louis Sorkin and Lorenzo Prendini for AMNH specimen loans, and two anonymous reviewers who made improvements to prior versions of this manuscript. Cave access permitted through IDNR approval received on January 26th, 2016.