K. Christiansen.
The Genus Pseudosinella (Collembola: Entomobryidae) in Caves of the United States.
Psyche 67:1-25, 1960.

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PSYCHE
Vol. 67 MARCH-JUNE, 1960 Nos. 1-2
THE GENUS PSEUDOSINELLA (COLLEMBOLA,
ENTOMOBRYIDAE) IN CAVES OF THE
UNITED STATES1
Grinnell College, Grinnell, Iowa
In 1934 Bonet listed two troglophile species of the genus Pseudo- sinella, P. deci$iens and P. sexocztlatn, from caves of the United States. In 1949 Delamare described two new troglobite species, P. hirsuta and P. spinosa, and placed them in a new genus Troglosinella. The present work is the result of the examination of more extensive collections from caves in the United States and has resulted in the addition of four more troglophile forms and the discovery of five new troglobite species. The work covered in this paper was made possible by a National Science Foundation Grant, No. 04563. Mr. Jerry Tecklin did much of the manual labor involved in preparation and he, Mr. James Hedges and Mr. George Darland, made a collecting trip through Missouri and northern Arkansas, recovering a good deal of critical material. Most of the remaining specimens were collected by Mr. and Mrs. Thomas Barr or Mr. Carl Krekeler. I wish to thank all of these people.
Distribution
Collections are relatively complete only from the region immediately around Tennessee and Kentucky; however, we have a sufficient scat- tering of material from other regions to be able to discern the probable outline of the distribution of the group. The species of this genus are more widespread in caves than those of the genus Sinella previously reported, but the troglobite forms are still largely limited to the southeast quadrant of the country. In the troglophile forms the ex- tensive invasion of the caves of Missouri and Arkansas is the most notable phenomenon. Generally speaking, the troglobite forms arc severely restricted in distribution and. in cases of numerous collections. more or less continuous. The troglo~hile forms are much more wide- 'Published with the aid of a grant from the Museum of Comparative Zoology at Harvard College.
I




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2 Psyche [March - June
spread and occur in widely disjunct populations. As was true in Sinella, the majority of the collections of troglophile forms falls out- side of the areas occupied by the troglobite species. Biology
Little accurate, detailed information is available concerning the biology of the members of this genus. The visible gut contents indicate that fungal hyphae and spores make up the major portion of the diet of most members. The incompleteness of the data on and collections of both cave and epigeic forms of this genus makes it difficult to classify the habitat of the various species. On a basis of present data we can place the forms described here into four groups: I) the definite troglo- GRAPH I
I
4th antennal segment
Graph 1. Curves showing the differing ratios of the fourth antennal seg- ment to the cephalic diagonal in the cave species of U. S. Pseudosinella. A includes: P. argentea, P. folsomi, P. duodecimpunctata, P. alba, and P. sexoculata; B: P. dubia; C (a probable average of several curves): P. hirsuta ; D: P. gisini; E: P. spznosa ; and F: P. boneti. bites - including P. spinosa, P. boneti, P. espana, P. hirsuta, and P. gisini; 2) the doubtful troglobites - P. dubia and P. orba; 3) the doubtful troglophile - P. argmtea; and 4) the definite troglophiles - P. petterseni, P. alba, P. folsomi, P. duodeci~?zj?wnctata, and P. sexoculata.




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19601 Christiansen - Genus Pseudosinella 3
Systematic Account : General Discussion
The genus Troglosinella was created by Delamare for the species hirwta and spinosa. Examination of much more extensive material encompassing several new species makes it clear that the generic limits set up by Delamare are impractical. Two of the most basic character- istics used to separate the genus (the ringing of the fourth antenna1 segment, and the small non-lamellate teeth) are present in some forms of hirsuta and absent in others. Beyond this the reduced tooth structure of the unguis appears in a number of separate epigeic forms. The spines of the dens, also used to separate the genus, are found in only one species (P. spinom) and the "heavy hairs" found on the dorsu~n of the dens in hirs.uta are found in large specimens throughout the whole of Pseudosinella. In view of this, and my failure to dis- cover any other practical way to separate the genus from Pseudosinella, I consider Troglosinella Delamare to be a synonym of Pseudosinella Schaffer. It is regrettable that this is unavoidable, since the species clustered around P. ~pinosa do represent an evolutionary unit. Ratios and Size
As with almost all groups of Collembola, the size of the species varies considerably. It is extremely risky to determine the size of a particular species upon anything except large samples from a variety of localities. Time and again a whole sample will be made up of small individuals, or will consist exclusively of extra-large specimens. With all this in mind it is possible to break the cave species of Pseu- dosinella of the United States into three size ranges: small (averaging around I mm.) - P. espana (?), P. alba, P. folsomi, P. duodecim- punctata, and P. sexoculata; medium (averaging between 2-3 mm.) - P. orba ( ?), P. boneti ( ?), P. duh'w, P. gisini, P. argentea and P. hirsuta ; and finally the large (averaging around 4 mm.) - P. spinosa. The ratios of the various organs vary, but if we consider all the species, almost any organ ratio can be expressed as a straight line, with one or two notable exceptions. The only striking exceptions involving several species concern the first and second abdominal segments and the length of the antennae. The latter is illustrated in graph I, which shows the most sensitive segment, the fourth, plotted against the cephalic diagonal. It can be seen that the most highly evolved cave forms develop progressively longer antennae. For most of the other organs a single straight line can express the growth changes and en- compass all species. Graph 2 shows a summary of such growth lines for organs of the various parts of the body. There are a few varia-



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4 Psyche [March - June
tions from the norm in several of these curves. The most striking is in connection with one population of P. hirsuta which has a longer fourth abdominal segment than is normal, and in all of the specimens examined of P. duodccimpunctata which have the manubrium, longer than is normal in the remaining species. It is quite probable that more exhaustive analysis will point out more such exceptions; however, it is apparent that there is little difference among the various species in most organ ratios.
The genus P~eudosine//a under any definition is a patently polyphy- letic group with characteristics largely determined by a particular ecology; it can be distinguished from its ancestral genus Lepidocyrtus upon only one basis - the reduction in the number of eyes. Pseudosi- nella usually shows additional characteristics in the loss of pigment and the modification of the unguis structure, either through great elongation and reduction in the size and number of inner teeth and/or through the enlargement of the basal inner ungual teeth. Within the North American cave forms there are three and possibly four separate evolutionary lines involved. Only one of these, the group including mm.1 .2 .3 .4 .5 .6 .7 -8 .9 1.0 1.1 1.2 1.3 1.4 GRAPH 2
Graph 2. Curves for five different organ ratios, each curve being a com- posite of all species. In the key below the ordinate is given first in each case. A: cephalic diagonal/second theoracic segment; B: cephalic diagonal/third tibiotarsus ; C : manubrium/mucrodens ; D : cephalic diagonal/mucrodens ; E: cephalic diagonal/fourth abdominal segment.



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19601 firistiansen - Genus Pseudosinella 5 P. spinosa, has gone through extensive evolution within the caves. In spite of the diverse origins of the species of this genus the forms are normally quite similar. The thorax has a somewhat enlarged second segment and the inucro is bidentate with a basal spine. The chaeto- taxy is very uniform with macrochaetae on the head being commonly numerous only along the antenna1 bases, between the antennae, and on the anterior half of the ventral surface. The mesothorax has a series of rows along the anterior margin, and the lateral surface of the fourth segment and the last two segments have sparse coverings. Scattered macrochaetae and groupings of from two to four odd, short, feathered setae and one long filamentous ciliate seta occur on the third and fourth abdominal segments (See figure 11). The scales are hyaline, finely striate and apically rounded. On the whole we have an artificial but readily separated genus. Key to the Cave Species of Pseudosinella of the United States Empodial appendage with a clear wing-like tooth at the end of a separate outer lamella .......................................................... 2 Empodial appendage with a small outer tooth or toothless ...... 4 Mucro without basal spine ............................. P. espana 11. sp. Mucro with basal spine ............................................................ 3 Unguis with median unpaired inner tooth ............ P. petterseni Unguis without median unpaired innner tooth ....... P. folsomi Dens with spines ....................................................... P. spinosa Dens without spines ............................................................... 5 With eyes ............................................................................. 6 Eyeless .................................................................................... I I .................................................. Two or fewer eyes per side
7
.................................................... Three or more eyes per side2 9
All inner ungual teeth small ................................................. 8 Basal, and sometimes all inner teeth large, two eyes per side ......................................................................................... P. aha Tenent hair weakly clavate and/or median unpaired inner ungual tooth absent ........................................... P. gisini 11. sp. Tenent hair acuminate, median unpaired inner ungual tooth present ................................................ eyed forms of P. hirsuta Three eyes per side on two separate eyepatches .... P. sexocula/~z Some members of each population with more than three eyes per side, always on one eyepatch ........................................... 10 All inner ungual teeth subequal, typically five eyes per side ............................................................................ P. dubia n. sp. *Occasional members of a population with four or more eyes may be eyeless-



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Psyche [March -June
Basal inner ung~~al teeth clearly larger than others, typically ................................
six eyes per side
P. duodecimpunctata
Fourth antennal segment more than two times as long as ................................................ cephalic diagonal
P. boneti n. sp.
Fourth antennal segment less than one and seven-tenths times .................................................... as long as cephalic diagonal
12
Distance from distal base of largest inner ungual tooth to base of unpaired inner tooth less than half that from unpaired tooth to apex of unguis (See figure 44)) macrochaetae present in median field of dorsum of head ............................ P. orba n. sp. Distance from largest basal inner tooth to median unpaired tooth at least half as great as distance from apical tooth to apex of unguis, macrochaetae absent from median field of doi-sum of head ........................................................................................ 1 3 One or both basal inner ungual teeth large and prominent (See figure 3 I ) , ratio of fourth antennal segment to cephalic diagonal less than .8 ................................................................ P. argentea Both basal inner ungual teeth small (See figure 47), and/or ratio of fourth antennal segment to cephalic diagonal greater than .8 .............................................. eyeless forms of P. hirsuta Figures 1-5: Pseudosinella duodecimpunctata. 1. Habitus, specimen from New River Cave, Giles Co., Va.; setae and pigment omitted; 19 X. 2. Hind claw. same specimen; 900 X. 3. Mucro, same locality; 900 X. 4. Apical organs, third antennal segments two different specimens, same locality; 900 X. 5. Eyes and eye patch, same locality; 900 X. Figures 6-11: P. dubia n. sp. 6. Habitus, specimen from Granny Dean Cave, Washington Co., Ark.; setae and pigment omitted; 18 X. 7. Apical
organ, third antennal segment, same specimen; 900 X. 8. Eye patch right side, same specimen; 250 X. 9. Mucro, same specimen; 500 X. 10. Hind claw, same specimen; 500 X. 11. Typical setae association of fourth abdominal segment, paratype ; 900 X.
Figures 12-16: P. sexoculata. 12. Habitus, specimen from Carlsbad Caverns, N. Mex., setae omitted, 30 X.
13. Mucro, same specimen, 900 X. 14. Apical organ third antennal segment, same specimen; 900 X. 15. Hind claw, same specimen; 900 X. 16. closeup of head, same specimen, A.-interantennal setae, B.-antenna1 base setae, C.-median field setae; 150 X.
Figures 17-21: P. alba. 17. Habitus, specimen from Niagra Cave, Fillmore Co., Minn.; 30 X.
18. Hind claw, same specimen; 900 X. 19. Apical organ, third antcnnal segment, same specimen; 900 X. 20. Mucro, same specimen; 900 X. 21. Right eye patch, specimen from Mystery Cave, Fillmore Co., Minn.; 300 X.
Figures 22-24: P. folsomi. 22. Apical organ. third antennal segment, speci- men from Limberlost Valley Cave, Newton Co., Mo.; 900 X. 23. Hind claw, same specimen; 900 X. 24. Mucro, epigeic specimen from Harahan, La.: 500 X.




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Psyche
[March - June
Descriptions of Species
Pseudosinella d'uodecimpunctata Denis
Figures 1-5
Pseudosinella duodeci~npz~nctata Dennis I 93 I, Mem. Soc. Ent. Ital. 10 :82.
P. (Pseudosinella) duodecimoculata Bonet I 93 I, Mem. Soc. Esph. N.H. 74 :324-6.
Facies typical of genus Lepidocyrtus. Background color yellowish white, with scattered blue pigment, particularly heavy along the sides of the thorax and head. Head broadly oval in shape with a clear V- shaped dorsal area marked off by pigment; six eyes per side on trape- zoidal eye patches. Antennae I .2-I .4 times as long as cephalic diagonal with third antennal segment in the form of a truncate cone clearly shorter than the second segment; apical organ of third segment with two irregular oval pegs in separate deep folds. Second thoracic slightly humped. Fourth abdominal segment about four times as long as third. Unguis with a clear external tooth and three inner teeth; basalmost of these usually salient and larger than remainder. Em- podia1 appendage lanceolate, with one or more minute external teeth. Tenent hair curved and clearly clavate. Mucro with apical tooth weakly upturned and longer than anteapical, basal spine attaining the apex of the anteapical tooth. Anterior macrochaetae as follows: on dorsum of head a group of four interantennal setae near the anterior margin and a curved row of seven setae along each antennal base, the anterior three being distinctly smaller; ventral surface with a few scattered setae near the anterior margin of the median and lateral areas. Second thoracic segment has a double row along the anterior margin.
Type locality: Buco de Piombo, Italy. Distribution : widespread in southern Europe in caves and epigeic. In North America the species has been taken in Florida, Massachusetts, and North Carolina as an epigeic form. In caves of the United States it has been taken from New River Cave, Giles County, Virginia; Wind Cave, Jackson County, Kentucky; Old Spanish Cave, Stone County, Missouri; Panther Cave, Newton County Missouri; and Foster's Cave, Mont- gomery County, Tennessee.
Discussion
The most striking variations seen in this troglophile species are in the number of eyes and amount of pigment. Most specimens have the twelve eyes characteristic of the species; but forms with ten eyes



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19601 Christiansen - Genus Pseudosinella 9 are common; rarely, specimens appear with fewer, as can be seen in those from Tennessee which have from none to six per side. The tibiotarsus of this population is slightly longer than is normal for the species, but they are otherwise similar to forms seen elsewhere. This would appear to be an example of cave evolution proceeding within a population and would be worth additional study. Pigment may be uniformly distributed over the whole body or limited to the head region. The apical organ of the third segment varies from the condi- tion described to two subcylindrical pegs. The identity of this species with the European specimens is still in doubt as no comparisons could be made; however, there appears to be good agreement between the descriptions and the specimens at hand. This species may very well be the same as P. collina, which was de- scribed by Wray ( 1952) as having only two internal ungual teeth; but until this can be checked the two species must be considered sepa- rate.
PsetidosineZla Mia, new species
Figures 6-1 I
Facies typical of genus. Background color white with an overall scattering of blue pigment, particularly dark on dorsum of head where it forms a diamond shaped mark between the eye patches. Head broadly oval; eyepatches elongate trapezoids, each bearing five eyes in two groups, an anterior group of three and a posterior group of two. Antennae about one and one half times as long as the cephalic diagonal; first three segments subcylindrical and fourth segment fusi- form. Fourth segment dorsally with numerous blunted smooth setae of several different sizes and shapes; apical organ of third segment with two irregular flattened elliptical rods in a fold, and about fifteen additional blunt curved setae scattered over the inner ventral surface of the segment. Second thoracic segment markedly humped forcing the head into a slightly hypognathous position. Fourth abdominal segment about five times as long as third. Unguis with minute basal external tooth and three small internal teeth, with basal-most inner tooth on a level and frequently appearing as one under low magnifica- tion. Empodial appendage lanceolate, with a small but clear external teeth, exceeding the level of the unpaired internal ungual tooth. Ten- ent hair weakly clavate. Mucro with apical tooth about twice as long as subapical, and markedly upturned ; basal spine exceeding the apex of subapical tooth.
Anterior maci-ochaetae as follows: on dorsum of head four interantennal setae, the posterior pair closer together, and



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10 Psyche [March -June
a curved row of eleven setae around each antenna base; ventral surface with a few scattered setae on the anterior median portion. Type locality: Devils Den Kitchen Cave, Washington County, Arkansas, IX-g-'5g, Tecklin, Hedges and Darland coil. Also taken from Granny Dean and Devils Den Caves, Washington Countv. Arkansas.
Discussion
The number of eyes varies considerably, most specimens having five per side. However, many have four per side; in such cases it is the posteriormost eye of the anterior three which is missing, and the position of this eye is variable even when it is present. The tenent hair varies from acuminate to markedly clavate. The taxonomic position, name and limits of this species are all moot. The species is clearly distinguished from the form called here P, duodcci71ip;tnctata. The antennae of ddia are longer, and the eye number typically different. The shape of the eye patch and distribution of the eyes are also different, as is the structure of both mucro and unguis. The question of the relationship between this form and Wray's coilina or Guthrie's Lepidocyrtus decemoculatus is less easily settled, The present species appears to differ from colhna in ( I) the number of eyes (six vs. five per side typically) ; (2) the relative lengths of abdominal segments three and four (collma one; four, dub'ta one: five + ) ; (3) antennal ratios ; and (4) the comparison of lengths of the manubrium and dens. In addition, Wray's figures show the basal spine of the mcro not reaching the anteapical tooth and the unguis EXPLANATION OF PLATE 2
Figures 25-30: P. pismi n. sp. 25. Habitus, specimen from Hi~genbotham Cave, Greenhrier Co., W. Va., setae and pigment omitted; 12 X. 26. Hind claw, paratype; 350 X, 27. Hind unguis, specimen from McFerrin Cave, Greenbrier Co., W. Va.; 250 X. 28. Mucro, same specimen ; 250 X. 29. Dor- sal setae and eyes right side, paratype, Greenbrier Co., W. Va.; A.-inter- antennals, R.-antenna1 base setae; 120 X. 30. Apical organ, third antennal
segment, specimen from McClung Cave, Greenbrier Co., W. Va. ; 350 X. Figures 31-37: P. ergentea. 31. Typical hind unguis, specimen from Eli Reed Cave, Larue Co., Ky.; 350 X, 32. Hind claw showing unusually large basal tooth, specimen from Rankin Cave, Jefferson Co., Mo.: 350 X. 3i. Hind unguis showing unusuallv small basal teeth, specimen from Crownover Saltpeter Cave, Franklin Co., Tenn.; 350 X. 34. Habitus, specimen from Mammoth Cave, Ky., setae omitted; 17 Xi 35. Apical organ, third antennal segment, specimen from Rankin Cave, Jefferson Co., Mo.; 900 X. 36. Same organ, specimen from Sparkman Cave, White Co., Tenn.; 900 X. 37. Mucro, same specimen ; $00 X.
Figures 38-42: paratypes of P. tipanu n. sp, 38. Habitus, setae omitted; 30 X. 39. Mucro; 900 X. 40. Apical organ, third antennal segment; 900 X. 41. Base of hind claw : 900 X. 42. Claw smaller specimen ; 900 X.



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12 Psyche [March -June
with two inner teeth. Both conditions differ in dubia. Lepidocyrtus decemoculatus is very poorly described, but every major described feature except the eye number would appear to indicate a separate species. The distribution of the eyes, the shape of the eyepatch, the hinted antennal ratios, and ratio of manubrium to dens all are differ- ent from those seen in dubia.
In any case, I feel that it is impossible to fit the present form into the descriptions of either species at this time. It is quite possible that close examination will show that this form is in fact synonymous with one or both of the species mentioned above. Pseudosinella sexoculata Schott
Figures I 2- I 6
Pseudosinella sexoculata Schott 1902, Bib. Kong. Sv. Vet.-Akad. Handl. 28: 34-5.
Lepidocyrtus sexoculatus Guthrie 1903, Publ. Geol. Nat. Hist. Survcy Minn. Zool. Series 4: 86-7.
P(sendosinella) sexoculata Bonet 1934, Arch. 2001. Exp. Gen. 76: 370.
Facies typical of genus Lepidocyrtus. Background color dull yellow, pigment limited to eyepatches. Head circular, eyes three per side on two separate eye patches, two eyes in front and one behind. Antennae with fourth segment fusiform, second and third segments truncately conical and first segment subcylindrical; third segment strikingly shorter than the second and with an apical organ consisting of two basally constricted oval pegs in a deep fold. Second thoracic segment not strikingly humped, so that the head is prognathous. Fourth abdom- inal segment about three times as long as the third segment. Unguis without external teeth, the basal pair arising at different levels. Empodial appendage lanceolate with outer margin serrate. Tenent hair large and clearly clavate. Mucro with apical tooth slightly larger than anteapical and markedly upturned at its apex; basal spine exceed- ing apex of anteapical tooth. Anterior macrochaetae as follows: dorsum of head with a curved row of six setae along each antennal base and a single seta between the two eyepatches on either side; four interantennals, more posterior than normal; a medium pair of setae between and slightly in back of the two posterior eye ~atches; ventral surface of head with scattered setae along the anterior one-fourth. Second thoracic with a double row of setae along the anterior margin. Type locality : epigeic greenhouses, Linkoping, Sweden and Rosen- dal, Norway.




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19601 Christiansen - Genus Pseudosinella I3
Distribution: a common epigeic form on the Pacific coast. Cave collections in the United States: Reids Cave, Fayette County, Ken- tucky; and Carlsbad Caverns, Eddy County, New Mexico. Discussion
This form appears to be a rare troglophile in caves in the United States. Further exploration and collecting in western caves may show it to be more common than presently appears. Pscudosinella alba ( Packard)
Figures I 7-2 I
Lepidocyrtiis albus Packard I 873, Peabody Acad. Sci. 5th Ann. Rept : 37-
Sira (Pseudosinella) alba Schaffer I goo, Jahib. Ver. Vaterl. Natur. 56: 269.
Pseudosinella alba Borner I 901, 2001. Anz. 24 : 707. Facies typical of genus Lepidocyrtus. Background color dull yel- low white with scattered bluish or brownish pigment. Eyes two per