Caecidotea bicrenata whitei Lewis & Bowman 1981

Caecidotea whitei

Crustaceans—Hubricht, 1942:35.

Asellus alabamensis.—Fleming, 1972a:247, 248 [in part].

Caecidotea sp. no. 1.—Peck and Lewis, 1978:44.

HISTORY.—The first record of Caecidotea whitei is in the report on Wet (= Cricket) Cave by Hubricht (1942), where he stated that “a large stream runs through the cave containing three species of crustaceans.” Although this is not a direct reference, the most common crustacean in the cave is C. whitei, and Hubricht presumably took note of it.

Fleming (1972a) identified specimens from Cricket Cave, Illinois, and numerous Kentucky caves as Asellus alabamensis, because of the similarity of the second pleopod endopod tips of the 2 species.

Peck and Lewis (1978) noted that Fleming's determination was erroneous and listed the species as an undescribed troglobite. Two additional cave localities near Cricket Cave were listed for the species.

MATERIAL EXAMINED.—ILLINOIS. Union Co.: Cricket (= Wet) Cave, leg. J. J. Lewis, 27 Jul 1976, 23, 34 (14 ovigerous); leg. L. Hubricht, 13 Jul 1940, 34, 69. Sensemeyer Cave, leg. J. J. Lewis, 27 Jul 1976, 5, 7. Roaring Spring, leg. J.J. Lewis, 27 Jul 1976, 10, 3; leg. L. M. Page, 21 Jan 1976, 20, 23; leg. Ross and Burks, 17 Oct 1938, 19, 18; leg. Burks and Riegel, 21 Jun 1939, 6, 4; leg. Mohr and Burks, 15 May 1940, 8, 9. Keith (= Musical) Cave, on Green Creek Tributary, 0.8 km (0.5 mi) N Jonesboro, leg. Jeffrey Webb, 19 Dec 1976, 2, 1; leg. J. J. Lewis, 12 May 1979, 3, 4. KENTUCKY. Barren Co.: Diamond Caverns, leg. J. R. Holsinger and T. C. Barr, 24 Jul 1964, 1, 4. Caldwell Co.: Watson's Cave, 3.2 km (2.0 mi) W Princeton, leg. J. R. Holsinger, Ginny Tipton, et al., 12 Jun 1978, 2, 4. Crittenden Co.: Kinnen Cave, ca. 6.9 km (4.3 mi) SW Marion, leg. J. R. Holsinger et al., 13 Jun 1978, 2, 4 ovigerous . Edmonson Co.: stream in small cave at mouth of Cotton Gin Hollow, leg. Leslie Hubricht, 12 Jan 1957. Hart Co.: Hidden River Cave at Horse Cave, leg. Leslie Hubricht, 30 Aug 1939, 44. Metcalfe Co.: Cave Hill Cave, leg. R. M. Norton, 2 Oct 1965, 2, 4; Route 68 Cave, leg. J. Cooper, 5 Jul 1967, 4, 1.Warren Co.: stream in cave near Laurel Avenue and Cabell Street, Bowling Green, leg. Leslie Hubricht, 25 Dec 1956, 9. TENNESSEE. Clay Co.: Sheales Cave leg. L. M. Ferguson and B. L. Ferguson, 25 Jul 1972, 4, 2.

A 6.2 mm from Cricket Cave is the holotype (USNM 172775). The other specimens from Cricket Cave and the Lewis collections from Sensemeyer Cave and Roaring Spring are paratypes.

DESCRIPTION.—Small, eyeless, unpigmented. Length of to 7.0 mm, of to 7.4 mm. Body slender, linear, about 4.5× as long as wide; coxae visible in dorsal view. Lateral margin of head slightly setose; margins of pereonites and telson moderately setose. Head about 1.7× as wide as long; anterior margin slightly concave; postmandibular lobes broadly rounded; posterior margin straight. Telson about 1.5× as long as wide; sides parallel; caudomedial lobe barely delimited.

Antenna 1 reaching midlength of last segment of antenna 2 peduncle; flagellum of about 7 segments, varying with age; esthete series not interrupted; esthetes present on last 3 (5.7 mm ), 4 (5.3 mm ), or 5 (5.8 mm ) segments. Antenna 2 reaching from pereonite 5 to midlength of telson in different individuals; last segment of peduncle about 1.9× length of preceding segment; flagellum with about 35–40 segments.

Mandibles with 4-cuspate incisors and lacinia mobilis; spine-row of both mandibles with 17 spines; apex of palp with 1 spine. Maxilla 1, apex of outer lobe with 13 spines and 1 subterminal seta; inner lobe with 5 apical plumose setae. Maxilliped with 5–6 retinacula.

pereopod 1 propus about 1.8× as long as wide, palm distal to midlength with large triangular mesial process separated by U-shaped cleft from smaller rounded distal process. Dactyl flexor margin with rounded proximal boss and about 4 distal spines. pereopod 1 more slender; propus about 2.8× as long as wide, palm lacking large spines or processes; dactyl flexor margin with about 4 distal spines. Pereopod 4 of much more setose than that of , dactyl medially with 2 spines and 1 seta, with 1 spine and 1 seta.

pleopod 1 about 1.2× length of pleopod 2; protopod about 0.7× length of exopod, with 3 retinacula. Exopod about 0.6× as wide as long; apical setae short, nonplumose; lateral margin with concavity bearing longer setae. pleopod 2 protopod medial margin with about 4 proximal spinules and 2 setae at midlength. Proximal exopod segment with 2–3 lateral setae; distal segment oval, with 6 long and 3–4 shorter setae. Endopod slender, with low proximal bosses; slightly concave laterally, with 2 apical processes; cannula curving laterally, beak-shaped; lateral process extending parallel to and nearly equal in length to cannula, cylindrical, apex bluntly rounded to truncate. pleopod 2 about 1.9× as long as wide, with 8 plumose setae on apex and distal half of lateral margin. Pleopod 3 exopod about twice as long as wide, with many lateral setae, fewer on apex and medial margin. Pleopod 4 with type B exopod lacking proximal marginal spines.

Uropod about 1.3× length of telson; protopod about 1.4×–1.5× length of endopod, 2.3×–4.2× length of exopod.

ETYMOLOGY.—Named after John White, prominent Illinois speleologist, who aided the first author in making many collections in Illinois caves.

RELATIONSHIPS.—Caecidotea meisterae is closest morphologically to C. whitei. The features of the pleopod 2 endopod tip are nearly identical in both species, although in C. meisterae the cannula is generally more pointed and the lateral process more expanded distally. The gnathopod propus of C. meisterae is ovate and more robust than the slender propus of C. whitei. Both species lack proximal processes along the palm, but have mesial and distal processes. In C. whitei the mesial process is low and subtriangular; it is similar in C. meisterae, but larger and more prominent, often developing into an uneven, bicuspate process (Figure 20). The distal process in C. whitei is only apparent in rather mature specimens, and then is low and rounded. In C. meisterae this process is quadrate and ranges from slightly to markedly bicuspate. The uropods of large C. meisterae are robust and somewhat spatulate, in contrast to the slender, cylindrical uropods of C. whitei.

Although we have chosen to treat this material as 2 species, it is possible that intermediate forms will be found proving them to be conspecific. The differences cited above have been consistent thus far, and of the large number of specimens of C. whitei examined from the type-locality and elsewhere, none contain large, robust specimens typical of C. meisterae collections. This seems to rule out the possibility that C. whitei is actually an immature C. meisterae.

Fleming (1973) considered the material we have described as C. whitei and C. meisterae, along with C.jordani as Asellus alabamensis. Fleming compared the type-material of C. jordani with topo-typic material of A. alabamensis (placed in the USNM by H. R. Steeves, III) and other specimens consdered to be conspecific with this species, including Illinois material. His conclusion was that C. jordani was a synonym of A. alabamensis. We have reexamined the type-material and topotypes and believe that C. jordani is a valid species (Figure 30). Of the assemblage previously considered as A alabamensis, C. jordani is the only species which possesses a proximal process on the gnathopod. This large, subtriangular process is prominent and readily separates C. jordani from all “alabamensis” species but C. beattyi, which also possesses a proximal process. C. jordani may be separated from C. beattyi by the much smaller distal biscuspate process on the gnathopod and the absence of the distolateral lobe present on the pleopod 1 of C. beattyi. C. jordani is also unique in possessing a 4-0-1-0-1 to 6-0-1-0-1 antenna 1 esthete formula. C. jordani is similar to C. antricola, C. meisterae, and C. whitei in the morphology of the endopod tip, the ovate exopod of the first pleopod and the type B pleopod 4. C. jordani is apparently a phreatobite, which does not occur in the numerous caves of the Monroe Co., Indiana karst.

We are reasonably sure that the material examined from Illinois, Indiana, and Kentucky is not Asellus alabamensis as reported by Fleming (1972a), but uncertainty still remains as to the taxonomic status of this species. The original description (Stafford, 1911) is insufficent to characterize the species, and the type-material has been lost. Steeves (1964) deposited material from Morgan Co., Alabama, as topotypes of A. alabamensis, but the type-locality was a well in Auburn, Lee Co., Alabama. Examination of Steeve's topotypes (Figure 31) revealed a marked disimilarity between the first pleopod of the topotypes and that illustrated by Stafford (1911). Stafford's drawing, although small, clearly illustrates a prominent distolateral lobe, such as that possessed by C. beattyi, which is not like that of the topotypes. The morphology of the topotypes more closely resembles that of specimens of C. bicrenata that have not reached maturity in their development of the gnathopod processes. Furthermore, the Morgan Co. locality from which the topotypes were taken lies in the cave region of northern Alabama from which C. bicrenata was described, rather than the Piedmont from which A. alabamensis was described. Until topotypes that more adequately resemble the original description can be collected from the Piedmont in the vicinity of Lee Co., it seems best to consider C. alabamensis as a separate, probably phreatobitic, species. Similarly, C. bicrenata can be recognized, at least for the time being, as a separate species inhabiting caves in northern Alabama.

Bresson (1955) redescribed A. alabamensis from Tennessee specimens which appear to be conspecific with material we have examined from central and southern Tennessee. According to the scenario which is proposed for C. alabamensis, Bresson's specimens cannot be referred to this name, but also they are neither C. whitei nor C. meisterae. We prefer not to attempt the application of either an old or new name to Bresson's asellid until the systematics of Caecidotea in the southern part of the Interior Low Plateaus cave region can be studied further.

HABITAT.—The Illinois localities listed above for C. whitei, except for Keith Cave, are parts of the same small cave system (Figure 32). The type-locality, Cricket Cave, is entered by a large, 25-foot-deep pit which intersects a large walking passage containing the stream. This stream is usually a few inches deep; however, when the cave was visited during December, 1973, the water had risen nearly a foot due to a snow melt. Only a single C. whitei was taken on this visit, despite a thorough search. On a July, 1976, visit, a large C. whitei population was found under stones in the stream and in mud-bottom pools (water temperature about 13° C). Sensemeyer cave is a few hundred feet from Cricket Cave; C. whitei is much less common in the gravel-filled pool examined in this cave. Roaring Spring, east of the 2 caves, is a stream flowing from the collapsed, unenterable part of the sysem.

RANGE.—Bretz and Harris (1961) discuss the geology of the type-locality, Cricket Cave, along with Roaring Spring and Sensemeyer Caves. These 3 caves are hydrologically connected in Mississippian Salem limestone; water from the caves returns to the surface at a spring which feeds a tributary stream of Mill Creek (Figure 32). In Illinois, C. whitei is known only from caves and springs in Union Co.

Caecidotea whitei is also known from caves of northwestern Kentucky, through the Mammoth Cave area in the central part of the state, to north central Tennessee. All of the known localities of this species occur within the Mississippian limestones of the Interior Low Plateaus Province, but the Illinois localities are very near the eastern margin of the Salem Plateau Section of the Ozark Plateaus Province.

Caecidotea meisterae

Asellus antricolus.—Fleming, 1972a:245 [Twin Level Cave, Kentucky, record].

Asellus alabamensis.—Fleming, 1972a:247, 248 [part].

Caecidotea sp. no. 2.—Peck and Lewis, 1978:44.

HISTORY.—The only published records of Caecidotea meisterae are several records of Asellus alabamensis and 1 of A. antricolus (Fleming, 1972a) referable to C. meisterae and a reference in a checklist of the subterranean invertebrates of Illinois (Peck and Lewis, 1978).

MATERIAL EXAMINED.—ILLINOIS. Johnson Co.: unnamed cave at White Hill, leg. Julian J. Lewis and Margaret A. Meister, 1 Nov 1975 (10.6 mm and 4 ovigerous , 8.3, 8.7, 9.7, 11.0 mm in length). The 10.6 mm is the holotype (USNM 172791), and the 4 are paratypes. KENTUCKY. Caldwell Co.: Cave Street Cave, leg. J. Holsinger, 7 Jul 1965, 1, 1. Lisanbys Cave, 1.9 km (1.2 mi) W Princeton Court House, leg. J. Holsinger, 9 Jul 1965, 3, 4; leg. J. R. Holsinger, Ginny Tipton, et al., 12 Jun 1978, 1, 4. Christian Co.: Thomas Cave, leg. Richard LaVal, 4 Jul 1964, 1. Crittenden Co.: Cannon Cave, leg. Barr and Andrews, 8 Jul 1965, 7, 6. Hart Co.: Burd Cave, leg. R. M. Norton, 18 Sep 1965, 2, 2. Livingston Co.: McElroys Cave, leg. J. Holsinger, 8 Jul 1965, 1, 2. Logan Co.: Robertson Cave, leg. J. Holsinger, 13 Aug 1965, 11, 7. Todd Co.: Haddon Cave, leg. Barr and Andrews, 16 Jul 1965, 2, 1. Sharon Grove Cave, Sharon Grove, leg. T. C. Barr, 30 Jun 1978, 8, 11. Twin Level Cave, leg. R. M. Norton, 18 Apr 1964. Trigg Co.: Taylor Cave, leg. J. Holsinger, T. C. Barr, 12 Aug 1965, 4, 17.

DESCRIPTION.—A medium-sized rather robust species, eyeless, unpigmented. Length up to at least 11 mm; body linear, pereonites slightly expanded in ovigerous females from dorsal aspect, about 4.3× as long as wide (9.5 mm ). Coxae visible in dorsal view. Lateral margins of head and pereonites moderately setose. Head about as long as wide, anterior and posterior margins slightly concave, postmandibular lobes low and rounded. Telson about 1.3× as long as wide, posterior margin slightly convex, caudomedial lobe low and not obviously developed.

Antenna 1 flagellum of about 8 segments, esthete formula 4-0-0. Antenna 2 (broken off in all type-specimens), last segment of peduncle about 1.6× length of preceding segment; flagellum with about 75 segments.

Mandibles with 4-cuspate incisors and 5-cuspate lacinia mobilis, with about 15–16 dentate spines or plumose setae in spine row (Figure 18d,e); palp with single large apical spine. Maxilla 1, apex of outer lobe with 13 large spines and 2 setae, 1 subterminal and 1 medial; inner lobe with 5 apical plumose setae. Maxilliped with 6 retinacula on right side, 7 on left; outer lobe with about 17 lateral spines and setae.

Male pereopod 1 propus about 1.4× as long as wide; palm convex, with large mesial process crowding lower bidentate distal process (Figure 20). Dactyl flexor margin with low rounded boss proximally and about 9 spines interspersed with small setae. Female pereopod 1 more elongate, propus about 1.9 × as long as wide, palm lacking processes, but with 2 large mesial process-like spines. Dactyl with 4 spines on flexor margin. Pereopod 4 similar in both sexes, with many spines and setae, dactyl with 2 spines in and .

Male pleopod 1 protopod about 0.7 length of exopod, with 3 retinacula on each side; exopod about 1.6× as long as wide, lateral margin very slightly concave, with many lateral and distal setae decreasing in length distally. Male pleopod 2, exopod proximal segment with 4 lateral plumose setae, distal segment with 7 long plumose distolateral setae and 4 shorter plumose medial setae; endopod with rather low, rounded basal apophysis, curving very slightly to the tip ending in 3 laterally directed processes: (1) bulbous lateral process proximal to and slightly shorter than cannula, broadly rounded apically; (2) cannula beaklike, curving slightly towards lateral process, tapering distally; (3) mesial process indistinct, bordering cannula and separated from it by shallow endopodial groove. Female pleopod 2 oval, about twice as long as wide, tapering somewhat distally, distal and lateral margins with 12–13 plumose setae, with gap separating proximal 3 from others, generally decreasing in length proximally towards a single nonplumose seta. Pleopod 3 about 1.9× as long as wide, with many lateral and medial spines and setae. Pleopod 4 exopod of type B, without marginal spines; false suture only slightly sigmoid.

Uropod with many lateral and medial spines and setae, endopod about 0.6× length of protopod, 2.2× as long as exopod; endopod and exopod tapering distally and bearing cluster of long apical setae.

ETYMOLOGY.—This new species is named for Ms. Margaret A. Meister, in gratitude for her assisting in the collection of invertebrates from numerous midwestern caves.

RELATIONSHIPS.—Caecidotea meisterae relationships are discussed under the species that it resembles closely morphologically, C. whitei.

HABITAT.—The type-locality is a small cave (Figure 11d) occupying a ridge called White Hill (at the town of White Hill). The cave consists of a small lower passage containing a few rock-filled pools, and a larger upper passage containing a single small mud-bottom pool where the isopods were collected. None of the Kentucky localities have been visited by us, but all records of C. meisterae are from caves, and it is apparently a troglobite.

RANGE.—Bretz and Harris (1961) discussed the geology of White Hill Quarry and a cave contained within the quarry. This quarry, which is reported to expose the Fredonia Limestone and overlying Rosiclare Sandstone, is very near the cave from which C. meisterae has been collected. In fact, discussion with local residents revealed plans to expand the quarry toward the area of the cave, which may destroy the cave in the future. The type-locality is presumably in the same Mississippian Limestone exposed in the quarry and formed under a sandstone cap. Bretz and Harris noted that White Hill is the southernmost of a group of isolated hills that may be relics of a pre-Cretaceous topography. White Hill is within the westernmost part of the Interior Low Plateaus Province, in the southern part of the Shawnee Hills Section (Willman et al., 1975).

Outside of Illinois C. meisterae is distributed through caves of western Kentucky eastward to the Mammoth Cave area in the central part of the state. Although we have examined no Tennessee material of this species, it is to be expected in the northwestern part of the state.

MATERIAL EXAMINED.—ILLINOIS. Adams Co.: Coe (= Dyers) Spring, Quincy, leg. Burks, Riegel, and Musselman, 8 Jun 1939, 1, 1 (INHS). Peters Spring, leg. Burks, Riegel, and Musselman, 8 Jun 1939, 2 (INHS). Pumpwell 10 mi (16 km) S Quincy, leg. J. G. Weise, 17 Sep 1957, 35, 13. Monroe Co.: Illinois Caverns, ca. 2 mi (3.2 km) S Burksville (also known as Morrison's Cave, Burksville Cave, Eckert's Cave, Mammoth Cave of Illinois), leg. Julian J. Lewis and Margaret A. Meister, 23 Nov 1974, 2 (broken, 5.3 mm, 9.8 mm), 1 (11.4 mm) (USNM); leg. J.J. Lewis and M. A. Meister, 16 Jun 1975, 1 (9.1 mm), 2 (7.8, 8.7 mm) (USNM); upstream from entrance on chert in water, leg. W. N. Netherton and D. Coons, 5 Dec 1977 (INHS). Halfmile Cave, leg. W. N. Netherton and D. Coons, 6 Jan 1978 (INHS). Dry Run Cave, in rimstone pool, leg. W. N. Netherton and D. Coons, 10 Jan 1978 (INHS). Fruths Spider Cave, leg. S. Peck, 26 Jun 1965, 1. Pautler Cave, leg. S. Peck, 27 Nov 1965, 1, 1. Pike Co.: Croxville Cave, 3.5 mi (5.6 km) NW Barry, leg. S. Peck, 15 Aug 1968, 7, 10. St. Clair Co.: Falling Spring Cave, leg. S. Peck, 28 Nov 1965, 1, 1. MISSOURI. Lincoln Co.: stream in Aker's Cave, 1.5 mi (2.4 km) N Silex, leg. L. Hubricht, 24 Jan 1943, 1, 1 (USNM).

DESCRIPTION.—Large, eyeless, unpigmented. Length of largest specimen examined 11.4 mm. Body slender, linear, about 4.4× as long as wide; coxae all visible in dorsal view. Margins of head, pereonites, and telson moderately setose. Head about 1.8× as wide as long, anterior margin concave, postmandibular lobes low and not especially produced. Pereonites 1–4 with small anterior shoulder-like projections, most pronounced in pereonite 3; 1–4 slightly laterally expanded in ovigerous females. Telson about 1.2× as long as wide, sides subparallel, tapering from anterior to posterior, caudomedial lobe not pronounced.

Antenna 1 extending to beginning of last peduncular segment of antenna 2; flagellum of about 10 segments; esthete formula 3-0-1. Antenna 2 reaching past posterior of telson, much longer than body; last segment of peduncle about 1.7× length of preceding segment; flagellum of about 90 segments.

Mandibles with 4-cuspate incisors and lacinia mobilis; spine-row of 11.4 mm with 19 large setae and 1 smaller terminal seta in right mandible, with 20 seta in left mandible; palp with 2 large distal spines. Maxilla 1, apex of outer lobe with 13 spines and 1 seta, 1 subterminal medial seta; inner lobe with 5 plumose setae (1 specimen had 6 plumose setae on right side). Maxillipeds with 5 retinacula on left, 6 on right.

pereopod 1 propus about 1.5× as long as wide, triangular; palm without proximal process, but with proximal defining spine, with large conical mesial process crowding shorter, rounded distal process and distal row of about 6 setae; dactyl flexor margin with rounded boss proximally. pereopod 1 slightly more elongate than male, little sexual dimorphism in processes of propus, about 12 setae in row; dactyl flexor margin with proximal rounded boss and about 8 distal spines. pereopod 4 similar to pereopod 4, dactyl with 3–4 medial spines and 1 seta, dactyl with 2 spines and 1 seta.

pleopod 1, protopod about 0.7× length of exopod, with 5 retinacula on each side. Exopod about twice as long as wide with 6 long setae distally and about 9 shorter setae interspersed; lateral margin concave, lacking setae.

pleopod, 2 protopod with about 6 medial setae. Exopod proximal segment with 5 short lateral setae; distal segment with about 20 long plumose marginal setae and 9 setules on medial margin. Endopod with low basal apophysis; tip ending in 4 processes: lateral process conspicuous, digitiform, curving proximad, directed ventrolaterad; mesial process short, apically rounded, directed distad, overlapping base of short cannula directed obliquely laterad; caudal process well sclerotized, broadly rounded, curving slightly laterad.

pleopod 2 with about 16 lateral plumose setae.

Pleopod 3 exopod with slightly concave distal margin. Pleopod 4 exopod type B, with 6 proximal spines on lateral margin.

Uropod very long and slender, cylindrical, 2.4× length of telson; protopod 4.1× length of exopod, 1.3× length of endopod.

ETYMOLOGY.—Not given, but obviously named for Alpheus S. Packard, Jr., pioneer American biospeleologist.

RELATIONSHIPS.—Caecidotea packardi fits without difficulty into the hobbsi group of Steeves (1966), but beyond that its affinities are uncertain. Several distinctive features—the long digitiform lateral process, the diminished sexual dimorphism in pereopod 1, and the very long slender uropods—set it apart from other known species.

HABITAT.—Caecidotea packardi is a troglobite and occurs in stream pools, riffles, and drip pools in limestone caves. It is occasionally flushed from subterranean waters and collected at springs or wells.

RANGE.—The caves which this species inhabits (Figure 1) are discussed in detail by Bretz and Harris (1961). The caves in the southern part of the range are primarily within the Mississippian St. Louis Limestone, while Burton Cave and probably the other Adams County localities are within the Burlington Limestone, also Mississippian in age. The Monroe and St. Clair county localities are within the Salem Plateau Section of the Ozark Plateaus Province, while the Adams County populations are slightly north of the Lincoln Hills Section of the Ozarks, lying within the Dissected Till Plains Section of the Central Lowlands Province (Willman et al., 1975). The single Pike County locality, Croxville Cave, apparently lies within the northernmost corner of the Lincoln Hills.

All of the localities from which Caecidotea packardi has been collected occur along the Mississippi River, and some occur in areas that were glaciated. Since some of the caves along the glacial margins probably were filled and buried by glacial deposits, these caves probably have been invaded (or reinvaded) by C. packardi since the Sangamon interglacial.