Nesticus barri Gertsch

Hedin, Marshal & DELLINGER, Bob, 2005, Descriptions of a new species and previously unknown males of Nesticus (Araneae: Nesticidae) from caves in Eastern North America, with comments on species rarity, Zootaxa 904, pp. 1-19 : 3-8

Nesticus barri Gertsch 1984

Figs. 1-10

Nesticus barri Gertsch, 1984: 36, figs. 121-123, 161-163.

Nesticus valentinei Gertsch, 1984: 29, figs. 150-152.

Material Examined. Nesticus valentinei Holotype. - Female, U.S.A: Tennessee: Marion County, Heatin Stove Monteagle Cave, coll. 30 May 1937, J.M. Valentine (housed at AMNH).

N. barri specimens examined U.S.A: Tennessee: Franklin County, Crownover Saltpeter Cave, 35°00' N, 84°54' W, 21 August 1999, coll. W. Reeves (1 female); Salt River Cave, ~ 2.1 km W of Gonce, Alabama, 34°59' N, 85°58' W, elev. 210 m, 24 March 1995, coll. M. Hedin & J. Hedin (3 females, 2 males); Lost Cove Cave, ~ 4.7 km N/NE of Sherwood, 35°07' N, 85°54' W, elev. 240 m, 23 Sept. 1992, coll. M. Hedin, J. Hedin, and S. O’Kane (2 females, 1 male); Keith Cave, 35°07' N, 86°00' W, elev. 320 m, 24 March 1995, coll. M. Hedin & J. Hedin (8 females, 1 male); Custard Hollow Cave, 24 April 1960, coll. T. Barr (5 females); Fishtrap Spring Cave, 6.4 km NNW S. Pittsburg, 28 August 1968, coll. S. Peck; Ranie Willis Cave, on Tennessee-Alabama Line, 13 January 1957, coll. T.C. Barr, Jr. (4 females); Marion County, Nickajack Cave, July 29 1967, coll. S. Peck & A. Fiske (3 females); Honeycutt Cave, 7 mi. NW S. Pittsburg, 28 August 1968, S. Peck (1 female); Tate Spring Cave, SE of Monteagle, 35°10' N, 85°48' W, elev. ~ 200 m, 15 August 2004, coll. M. Hedin, L. Hedin, R. Keith, J. Starrett and S. Thomas (2 females, 1 male). Alabama: Jackson County, Guess Creek Cave, ~ 4.8 km E Trenton, 34°45' N, 86°11' W, elev. 240 m, 25 Sept. 1992, coll. M. Hedin, J. Hedin, and S. O’Kane (8 females); Marshall County, Bishop Cave, ~ 4.8 km N of Guntersville Dam, 34°27' N, 86°21' W, elev. 300 m, 25 Sept. 1992, coll. M. Hedin, J. Hedin, and S. O’Kane (9 females).

Remarks - Gertsch (1984) states that the holotype of Nesticus valentinei was collected "from Monteagle Saltpeter Cave, 3.9 mi. SE Monteagle, Marion County, Tennessee, 30 May 1937 (J.M. Valentine), in American Museum of Natural History". Although the holotype specimen matches the species description and illustration, the collection label in the vial does not match Gertsch's cited location. The label, which appears to be original, actually reads "Heatin Stove Monteagle Cave Tenn. V·30·37 J.M. Valentine".

Our research indicates that this discrepancy is most likely the result of an error in label transcription by Willis Gertsch. Heatin’ Stove Cave and Monteagle Saltpeter Cave are geographically proximate caves (within ~ 5 km of one another), but are not the same cave. While Monteagle Saltpeter Cave is well-known (see Barr 1961), references to Heatin’ Stove Cave cannot be found in the standard literature on Tennessee caves (e.g., Barr 1961; Matthews 1971, 1994), and the cave location is not known to current members of the Tennessee Cave Survey (C. Akins, T.C. Barr, G. Moni, pers. comm.). However, with the help of T.C. Barr and L. Matthews, we were able to locate a literature reference to a "Heating Stove Cave" that is in Marion County, southeast of Monteagle, Tennessee. The cave description is from the early 1940s, but was not transcribed (by L. Matthews) and published until 1985 (Kirby-Smith 1985). Given the described location of this cave, it is likely that the cave entrance was destroyed during the construction of a major interstate highway (I-24). Our recent survey work is consistent with this scenario - following the landmarks cited in Kirby-Smith (1985) leads one directly to the interstate. We believe that the destruction of the cave entrance explains the current lack of familiarity with this cave by local cavers.

Kirby-Smith (1985), referring to Heating Stove Cave, notes that "the general slope is to the left … presumably to Tate Spring Creek". Also, in reference to Tate Spring, he notes that "this (the spring) is located 200-300 yards down cove from the Heating Stove Cave". Based on these indications, we reckoned that Heating Stove cave passage might be physically connected to Tate Spring, and recently attempted to re-collect N. valentinei in the navigable cave passage that lies behind the spring outlet. These collections were successful, resulting in the collection of two adult female and one adult male Nesticus . These specimens are discussed and illustrated below (Figs. 2 & 9). We have also collected in Monteagle Saltpeter Cave. Several adult Nesticus specimens have been collected, but all belong to the new species, Nesticus pecki, males and females of which differ in many ways from holotype N. valentinei and Tate Springs specimens (see species description below).

Synonymy - Comparing the holotype female of N. valentinei (from Heating Stove Cave) to Tate Springs females suggests that these specimens are from the same population (consistent with the continuous cave passage hypothesis). Although the disarticulated holotype is smaller-bodied than Tate Springs females, the holotype is clearly long-legged and troglomorphic, like Tate Springs females (Table 1). More importantly, the epigynum of these specimens is essentially identical (compare Figs. 2 & 3). Additional comparison of Heating Stove/Tate Springs specimens to specimens of N. barri suggests species synonymy. Nesticus barri is a troglomorphic species with almost 50 recorded cave-limited populations known from the southern edges of the Cumberland Escarpment in southern Tennessee and northeastern Alabama (Gertsch 1984; Peck 1989; Fig. 1). Several published records from Franklin and Marion counties in Tennessee are from caves close to Tate Springs and Heating Stove caves (within 10 km). The epigynal configuration of N. barri varies across populations (see Figs. 4-8), but we consider the condition seen in the Tate Spring/ Heating Stove population as within the realm of this variation. Although one could argue for the existence of multiple cryptic species, mtDNA data gathered from several populations of N. barri places these populations together as a single, albeit diverse, genetic clade (Hedin 1997a). We predict that DNA data from the Tate Springs/Heating Stove population will place these specimens into this same genetic clade.

An adult male Nesticus was never collected from Heating Stove Cave, but consideration of the Tate Springs male specimen further suggests synonymy with N. barri. The paracymbium is particularly similar, with a distal and ventral paracymbium that is essentially unmodified, and a simple, thin dorsal process (compare Figs. 9 & 10; also see Gertsch 1984, figs. 121-123). There is variation in the shape of the tegular apophysis across populations (Figs. 9 & 10), but the condition seen in the Tate Springs male is very close to that illustrated by Gertsch (figs. 121-123). Again, we interpret this as geographic variation in a single, dispersal-limited, species.

Although N. valentinei has page priority, we prefer to merge the single N. valentinei population with the many known N. barri populations. This decision is consistent with Article 24.2 (determination by first reviser) of the International Code of Zoological Nomenclature ( ICZN, 4th edition).

DNA sequences. - Mitochondrial 16S (Genbank accession numbers AF 004596 - 99) and nuclear ITS ( AF 003769 - 70) DNA sequences for several populations of N. barri were reported in Hedin (1997a).