Rotifera, Monogononta, Gnesiotrocha, Flosculariida E)

Zootaxa 4442 (2): 307– 3 1 8 I SS N 1175-5326 (print edition) htt p:// w w w. ma press.c o m/j/zt/ A rti cl e ZOOTAXA Copyright © 2018 Magnolia Press ISSN 1 1 7 5- 5 3 3 4 ( o nli n e e diti o n) htt ps:// d oi. or g/ 1 0. 1 1 6 4 6/ z o ot a x a. 4 4 4 2. 2. 7 http://zoobank.org/urn:lsid:zoobank.org:pub:49141 B9 2-B4B7-4594-B8B9-AC9F6 D D52BCF

Key to the currently recognized species of Li mnias Schrank, 1803 ( Rotifera, Monogononta, Gnesiotrocha, Flosculariida e)

ROBERT LEE WALLACE 1, 4 , AZAR KORDBACHEH2 & ELIZ ABETH J. WALSH3 1 OR CI D 0000-0001-6305-4776 D e p art m e nt of Bi ol o gy, Ri p o n C oll e ge, Ri p o n, WI, 5 4 9 7 1, U S A 2 OR CI D 0000-0001-5804-4805 D e p art m e nt of Bi ol o gi c al Sci e n c es, 5 0 0 W. U ni v ersit y Av e., U ni v ersit y of Te x as at El P as o, El P as o, T X, 79968, USA 3 OR CI D 0000-0002-6719-6883 D e p art m e nt of Bi ol o gi c al Sci e n c es, 5 0 0 W. U ni v ersit y Av e., U ni v ersit y of Te x as at El P as o, El P as o, T X, 79968, USA 4 Corresponding author. E- mail: wallacer @ripon.edu

A bst r a ct

Alt h o u g h t h e m ost wi d el y us e d k e y t o t h e R otif er a s u bsu mes six species of the sessile genus Li mnias within t wo species gr o u ps ( L. c er at o p h ylli a n d L. m eli c ert a ), t h e ori ginal descriptions of these for ms are sufficiently different to recognize t h e m as disti n ct e ntiti es. We us e d t h es e d es cri pti o ns a n d all a v ail a bl e lit er at ur e o n t h es e s p e ci es t o develop dichoto mous and for mula keys to the six species based on easily recognizable morphological characters. As part of our revie w we added relevant ecological infor mation fro m published sour c es, as w ell as o ur o w n d at a. We als o dis c uss t h e n e e d f or a d diti o n al o bs er v ati o ns of m or p h ol o gi c al, b e h a vi or al, lif e history, and genetic features to better understand the di v ersit y of t his wi d e- spread genus.

K e y w o r ds: bi o di v ersit y, distri b uti o n, m or p h ol o g y, t a x o n o m y

Introduction

Genus Li mnias Schrank, 1803 is one of nine genera of the gnesiotrochan fa mily Flosculariidae within Rotif er a. Species are diagnosed by their distinctive tube mor phology, length of ventral antennae, and nu mber of disti n cti v e nodules located on the dorsal surface of the neck. Hlava (1908) produced a workable key to the species, b ut us e d the dorsal nodules as a pri mary character; these ar e difficult to see without taking great care. Seventy years later K ost e ( 1 9 7 8) s u bs u m e d all si x s p e ci es i nt o eit h er o n e of t w o s p e ci es gr o u ps: L. c er at o p h ylli a n d L. m eli c ert a . We aver that Koste’s interpretation was un warranted, as he provided no detailed analysis of the variabilit y of distinguishing characteristics used by Hlava to delineate the species. Moreover assigning all species wit hi n t w o groups leads to a loss of infor mation regarding their ecological and genetic differentiation. On the other hand, vie wing these taxa as separate species provides the basis for developing more robust hypotheses of rel ati o ns hi ps, per mitting better phylogenetic assess ment of the ge nus using additional morphological characters and m ol e c ul ar d at a. Here we present t wo practical, morphologically base d keys: dichoto mous and for mula. To do our analysis w e revie wed descriptions fro m the original authorities and consulted previously published keys. As part of t his c o ntri b uti o n w e i n cl u d e d e c ol o gi c al i nf or m ati o n fr o m published sources, as well as our o wn data. As ap pr o pri at e we cite reference nu mbers for speci mens deposited i n The Acade my of Natural Sciences of Philadelphia [ A N S P] (no w The Acade my of Natural Sciences of Drexel Univ ersity) and pictured in Jersabeck et al. (2003), an d i n t h e R otif er W orl d C at al o g ( htt p:// w w w.r otif er a. h a us d er n at ur.at/ S p e ci es/I n d e x/ 3 8 7).

Accepted by H. Segers: 18 May 2018; published: 2 Jul. 2 0 1 8 3 0 7 Licensed under a Creative Co m mons Attribution License http://creativeco m mons.org/licenses/by/3.0 Genus Li mnias Schrank, 1803

Type species. Li mnias ceratophylli Schrank, 1803

Diag nosis. Elongate body (head, trunk, foot), sessil e a d ults i n h a biti n g a disti n ct t u b e i n t h e s h a p e of a pi p e ( Fi g. 1). Juveniles (larvae) are free-s wi m ming. Tube base oft en begins as a short, nearly featureless, hyaline ( clear), plai n cylinder, that abruptly changes above; tube widens fro m the base to the top (~2x base dia meter). Tubes eit h er straight, curved, or t wisted, constructed with eith er annulated rings ce mented on top of one another or as a continuous granular (stucco) matrix, so meti mes with transverse ro ws of minute raised apices (points), wit h or wit h o ut a d h eri n g d e bris, i n cl u di n g s a n d gr ai ns. A d ult tube length varies fro m ~400 to ≥1500 µ m. Corona wit h o n e p air of disti n ct l at er al l o b es, e a c h sli g htl y wi d er t h a n t all, wit h a v e ntr al d e pr essi o n ( c o n c a v e si n us) us u all y pr es e nt, eit h er sli g ht or str o n g: i. e., pr o vi di n g a n ill usi o n of a le mniscate (∞ ). A dorsal gap of varying widt h is a p p ar e ntl y present in all species. Dorsal antenna short; ventr al antennae short or long. So me species possess short nodules (protuberances) located anteriorly just beneath the corona on the dorsal side (n = 0–14). Foot long, p e d u n cl e a bs e nt, b ut a s h ort a d h esi v e dis c m a y b e pr es e nt at its b as e.

FI G U R E 1. Representative morphology of t wo species of Li mnias. ( A) Li mnias melicerta in ventral vie w. ( N B: Ventral antennae on the opposite side obscured.) Inset: Regi o n of d orsal n o d ul es: ( 3 r o ws: 2, 3, 2). ( B) L. m eli c ert a i n 3/ 4t h v e ntr al vi e w. ( C) Li m ni as c er at o p h ylli i n 3/ 4t h v e ntr al vi e w. S y m b ols: a = al g a e a n d d e bris; b = a d ult b o d y; c = c or o na; d n = d ors al n o d ul es; e = a mictic e mbry o; f = foot; rt = ringed tube; s = s ubstratu m; st = stucco-like tube ( with adhering epi phytes and debris); va = ventral antennae; bars ~100 µ m. (Photo micrographs B and C are courtesy of Michael Ple wka.)

With one exception all populations that have been r eported are sessile, solitary, occasionally for ming s m all branching colonies of up to ~30 individuals. Larvae p oss ess t w o r e d e y es p ots, l ost i n a d ults. A mi cti c reproduction is oviparous, oldest e mbryos most proxi mal to tube base. Males poorly described in one species. Diapausi n g e mbryos undescribed. Tr o p hi m all e or a m at e: r a mi sli g htl y as y m m etri c al; m aj or t e et h o n u n ci r e p ort e d as 3/ 3 or 4/ 4. C o m m e nts. T h e et y m o n of t his g e n us ( L., li m n os, l a k e) is a n all usi o n t o t h e g e n er al h a bit at of t h es e a ni m als. T wo species groups are recognized based on tube str ucture: L. ceratophylli and L. melicerta ( Koste 197 8).

3 0 8 · Zootaxa 4442 (2) © 2018 Magnolia Press W A L L A C E E T A L. Enu meration of the dorsal nodules is fro m the anteri or t o t h e p ost eri or. W hil e t h e y m a y b e s e e n w hil e t h e a ni m al is f e e di n g, d et er mi ni n g t h eir n u m b er, p ositi o n, a n d s h a p e is b est d o n e w h e n t h e c or o n a is r etr a ct e d a n d t h e a ni m al h as b e e n r e m o v e d fr o m its t u b e.

Dichoto mous key to Li mnias species

1 Tube annulated: a series of stacked rings (collars or girdles), often transparent, so meti mes slightly colored; ventral antenn ae s h ort or l o n g; d ors al n o d ul es pr es e nt ( 4, 7, or 1 4) ( Fi g. 1 A, B) ...... 2 - Tube not annulated: stucco-like, often opaque, with a granular matrix or covered with transverse, p arallel ro ws of minute raised apices (points); tube may be coated with debris; v e ntr al a nte n n a e s h ort or l o n g; d ors al n o d ul es present or absent. ( Fig. 1 C) ...... 4 2 T u b e gre atl y c ur v e d a n d/ or t wist e d, r ar el y str ai ght; length ~400–500 µ m; ventral antennae long; dorsal nodules present (n =4, i n 2 r o ws: 2, 2) ( Fi g. 2 A) ...... L. c or n uell a - T u b e str ai g ht or o nl y sli g htl y c ur v e d; t u be le n gth >500 µ m; ventral antennae short; nu mber and patt ern of dorsal nodules varies ...... 3 3 D ors al n o d ules pr es e nt ( n = 7, i n 3 r o ws: 2, 3, 2) ( Fi g. 1 A, B) ...... L. m eli c ert a - Dorsal nodules present (n=14, in 3 ro ws (6,6,2) ( Fi g. 2 B) ...... L. ny m p h a e a 4 Ventral antennae short; dorsal nodules absent (Fi g. 1 C) ...... L. c er at o p h ylli - Ve ntr al a nt e n na e l o n g; d ors al n o d ul es pr es e nt ...... 5 5 Tube slightly curved; dorsal nodules present (n= 2) ( Fi g. 3 A) ...... L. m yri o p hylli - Tube straight, surface covered with transverse, p ar all el r o ws of mi n ute r ais e d a pi c es ( p oi nts) ( Fi g. 3 B); dorsal nodules present ( n = 7, i n 4 r o ws: 1 [ bif ur c ate], 2, 2, 2) ...... L. shia wasseensis

For mula key to Li mnias species

1 Tube surface seen as annulated rings (Fig. 1 A, B) 2 Tube surface seen as stucco-like (granular), with or wit h o ut d e bris ( Fi g. 1 C) 3 Ventral antennae short (Fig. 1 B, C) 4 Ventral antennae long (Fig. 2 A) 5 Dorsal nodules absent 6 Dorsal nodules (n=2) 7 Dorsal nodules (n=4 in 2 ro ws: 2,2) (Fig. 2 A) 8 D ors al n o d ul es ( n = 7 i n 3 r o ws: 2, 3, 2) ( Fi g. 1 A) 9 Dorsal nodules (n=7 in 4 ro ws: 1 [bifurcate], 2,2, 2) 10 Dorsal nodules (n=14 in 3 ro ws: 6,6,2) (Fig. 2 B)

S p e ci es L. c or n u ell a 1, 4, 7 L. m eli c ert a 1, 3, 8 L. n y m p h a e a 1, 3, 1 0 L. c er at o p h ylli 2, 3, 5 L. m yri o p h ylli 2, 4, 6 L. s hi a w ass e e nsis 2, 4, 9

Li mnias ceratophylli Schrank, 1803 Fi g. 1 C

Melicerta biloba Ehrenberg, 1832 Li m ni as s oci alis L ei d y, 1 8 7 4

Types: None designated Type locality: Bayern ( Ger many). Other material: Speci men Preparation A NSP 793.

KE Y TO LI MNIAS Zootaxa 4442 (2) © 2018 Magnolia Press · 3 0 9 Diagnosis. Base of tube straight or slightly curved, clear at base, abruptly changing to stucco-like gr a n ul ar s urf a c e t o t h e t o p; t u b e m a y b e li g ht t o d ar k br o w n (opaque), depending on water conditions. Solitary or c ol o ni al. Ventral antennae short. Dorsal nodules absent. Dors al g a p i n c or o n a l ess t h a n n e c k wi dt h. T u b e l e n gt h ≤ 1 5 0 0 µ m. Tr o p hi: u n ci l o n g est t o ot h ~ 1 4 µ m; 3 ( 4 ?) p airs of m ai n t e et h. A mi cti c e m br y os: c a. 2 5 7 x 8 8 µ m. M al es k n o w n; diapausing e mbryos not described. Considered to hav e a c os m o p olit a n distri b uti o n. Measure ments: Total length, ≤1500 µ m; corona width, 1 2 5 – 1 8 3 µ m; t u b e l e n gt h, ≤ 8 0 0, t u b e wi dt h ( at t o p), ≈ 8 0 µ m; a mi cti c e g g, 4 0 – 5 0 x 1 0 0 – 1 1 0 µ m. S e e als o K oste (1978). Putative male poorly described by Huds o n a n d Gosse (1886: 76). Geographic range: Apparently cos mopolitan: Africa ( Senegal), Australia, Europe (France, Russia, U. K.), N ort h A m eri c a ( C a n a d a, U. S. A., M e xi c o), S o ut h A m eri c a ( Br a zil, E c u a d or, P a n a m a), T h ail a n d. Ecology: p H, 6–9.6; bicarbonate, 7.3–396 mg/ L, cond uctivity, 77 –663 µS/c m 2 , te mperature, 13–30 ° C; colonizes inert materials (glass and stones), sub merged logs, algae, aquatic moss (Fontinalis ), several vascular hydrophytes, including Ceratophyllu m, Elodea, Myrio phyllu m, Pota mogeton, Ranunculus, Utricularia ), and a n ani mal (crocodile) ( Ed mondson 1944; Koste 1978; Mag nusson 1985; Meksu wan et al. 2011; Nilsen and Lari m or e 1973; Sar ma et al. 2017; Tiefenbacher 1972; pers. o bs.). It so meti mes for ms moderately sized allorecruiti v e c ol o ni es, b ut its pr o p e nsit y t o f or m c ol o ni es h as n ot b e e n st u di e d. A pl a n kt o ni c p o p ul ati o n h as b e e n r eported (see b el o w). Co m ments. The ety mon of this genus is apparently a reference to the plant substratu m on which Schrank (1803) found speci mens. See Koste (1978) for additi onal synony ms. Tiefenbacher (1972) reported that he di d n ot see the periodical production of tube material, as in the way that Li mnias melicerta deposits its tube i n ri n gs ( Wright 1954), and that colony for mation occurred at hi g h p o p ul ati o n l e v els. Four curious habitats have been reported for L. cer at o p h ylli : t hr e e s essil e a n d o n e pl a n kt o ni c. ( 1) L eidy (1874) r e p ort e d a p o p ul ati o n att a c h e d t o st o n es i n a n u n d efi n e d r e gi o n of t h e S c h u yl kill Ri v er ( P hil a d el p hi a, Pennsylvania, U.S. A.) where colonies of up to 50 individuals occurred. (2) Nilsen and Lari more (1973) reported popul ati o n densities reaching 17 inds/c m 2 on sub merged, bark-less logs. (3) Magnusson (1985) n ot e d L. c er at o p h ylli t o b e a n epizootic on an A mazonian crocodile. (4) Although L. ceratophylli has al ways been considered to be sessil e, B e a c h (1960) reported abundant planktonic populations in t wo lakes out of approxi mately 25 lotic and lentic h a bit ats exa mined in the Ocqueoc River syste m, Presque Isle Co. ( Michigan, U.S. A.). Regrettably Beach did not st at e whether he exa mine hydrophytes for sessile individu als, but he i mplied that: L. ceratophylli “ … was al w a ys present and al ways free-s wi m ming.” In one lake the mean population level over three su m mers was ~900 i n ds/ L. Beach suggested that his findings of L. ceratophylli as an “adventitiously planktonic” was not fro m th e a ni m als b ei n g disl o d g e d fr o m t h eir s essil e att a c h m e nt b y w at er m o v e m e nts, b ut r at h er t h at l o c al f a ct ors of l a k e morphology and water che mistry accounted for this unusual condition. Unfortunately, no dra wings or photo micrograp hs w er e pr o vi d e d t o s u bst a nti at e t h es e o bs er v ati o ns. Wit h o ut t h at l e v el of d o c u m e nt ati o n t h e p ossi bilit y r e m ai ns t h at B e a c h was mistaken and that the organis ms he observed wer e tintinnids or another s mall, encapsulated plankto ni c organis m. Ho wever, apparently Beach was fa miliar wit h ti nti n ni ds, s u c h as C o d o n ell a s p., w hi c h h e r e p ort e d b ei n g pr es e nt i n t h e fr es h w at er s yst e m h e st u di e d. T h us, w hil e his r e p ort m a y b e i n err or, it c a n n ot si m pl y b e dis miss e d.

Li mnias cornuella Rousselet, 1889 Fi g. 2 A

Types: None designated Type locality: Hot-house tank; Gardens of the Royal Botanic Society, Regent’s Park ( U. K). Diagnosis. Tube ringed as in melicerta species grou p, s m all er ( 1/ 2 x) i n si z e t h e n eit h er L. c er at o p h ylli ( ≤ 1 5 0 0 µ m) or L. melicerta (≤500 µ m); curved or t wisted; transparent at base and top and opaque bet ween. Ventr al antennae long. Dorsal gap in corona unkno wn. Koste (1978) reports dorsal nodules as either 4 or 10. Co m ments. The ety mon of this species ( L., cornu, hor n + L., ell a , di mi n uti v e) is i n r ef er e n c e t o t h e s h a p e of the tube. Trophi: no available infor mation. A mictic, male, and diapausing e mbryos undescribed. Apparentl y t his species has not been reported since the original description of Rousselet (1889). Placed as a subspecifi c t a x o n within the L. melicerta species group by Koste (197 8). Although this species was presented as species inquirenda by Segers (2007), it may be distinguished fro m other me mbers of the L. melicerta species co mplex by its l o n g ventral antennae and the nu mber of dorsal nodules ( n = 4).

3 1 0 · Zootaxa 4442 (2) © 2018 Magnolia Press W A L L A C E E T A L. FI G U R E 2. T wo very rare Li mnias species, each of which has been reported only once. ( A) Li mnias cornuella ( Line art of four figures fro m Rousselet, 1889); ( B) Li mnias ny mphaea ( Line art of three figures fro m Stenroos, 1898). S y mbols: dn = dorsal n o d ul es; rt = ri n g t u b e; s = s u bstr at u m.

Cephalosiphon li mnias Ehrenberg, 1853 Li mnias corniculata Ehrenberg, 1853 Li mnias annulatus Bailey, 1855; na me a mended to ann ulata to agree with fe minine genus na me Li mnias doliolu m Schoch, 1868 M eli c ert a c u bitti C u bitt, 1 8 7 1; t e xt r efers t o M. a n n ul at a , b ut pl at e 9 8 l a bels as M. c u bitti Li mnias granulosa Weber, 1888 Li m ni as m eli c ert a m eli c ert a : K ost e, 1 9 7 8

Types: None designated Type locality: Afrossi mov Estate, St. Petersburg, R ussi a. Other material: Speci men Preparation A NSP 1527. Diagnosis. Base of tube clear, s witching abruptly t o a series of clear, stacked rings. Ventral antenna e s h ort; d ors al n o d ul es pr es e nt ( n = 7 i n 3 r o ws: 2, 3, 2). D ors al g a p i n c or o n a cili ati o n a p pr o xi m at el y e q u al t o n e c k wi dt h. Tr o p hi: r a mi as y m m etri c al; u n c us wit h 3 str o n g m ai n t e et h. Measure ments: Total body length, ≤1550 µ m; corona wi dt h, 1 6 0 µ m; h ei g ht, 7 0 µ m; t u b e wi dt h ( at t o p), ≈ 1 0 0 µ m; a mi cti c e g g, 1 3 0 – 2 4 2 x 4 0 – 9 8 µ m. S e e als o K ost e ( 1 9 7 8). Geographic range: Apparently cos mopolitan: Africa ( De mocratic Republic of the Congo), Australia, Europ e ( Fr a n c e, G er m a n y, Ir el a n d, R ussi a, U. K.), I n di a, N ort h A m eri c a ( C a n a d a, U. S. A., M e xi c o), S o ut h A m eri c a ( Br a zil, Ecuador), Thailand. E c ol o g y: p H, 4. 1 – 8. 9; bi c ar b o n at e, 5 7 – 3 0 5 m g/ L; c al ci u m, 5 – 3 8 m g/ L; m a g n esi u m, ≤ 2 0 m g/ L, c o n d u cti vit y, 81–686 µS/c m 2 , te mperature, 18–32 ° C; colonizes a wide variety of substrata such as glass, charophyte algae (Chara , Nitella ), aquatic mosses (Fontinalis , Sphag nu m), and vascular hydrophytes including Ceratophyll u m , Elodea, Eriocaulon, Le mna, Lud wigia, Myriophyllu m , Nuphar, Ny mphaea , Pota mogeton, Ranunculus, and Utri c ul ari a ( B ail e y 1 8 5 5; Fr a n c e z 1 9 8 4 b; K elli c ott 1 8 8 8; K ost e, 1 9 7 8; S ar m a et al . 2 0 1 7; Wall a c e 1 9 7 7; Ya n g & Hochberg 2018; pers. obs.). Ed mondson (1944) suggests t h at fl at s urf a c es pr o vi d e s uit a bl e s u bstr at a. Co m ments. The ety mon of this species ( G., meli , hon ey + G., keras, horn) is apparently in reference to t h e c ol or t h at t h e t u b e of t his s p e ci es m a y t a k e. M al e and diapausing e mbryos undescribed. Construction of t h e ri n g e d t u b e (ri n gs ~ 5- 1 0 µ m i n h ei g ht) is b y a n el a b or at e b e h a vi or of t h e a ni m al ( Wri g ht 1 9 5 4).

Li mnias myriophylli ( Tate m, 1868) Fi g. 3 A

Li m ni oi d es m yri o p hylli Tat e m, 1 8 6 8 Li m ni as m yri o p h ylli ( Tat e m): West er n, 1 8 9 1

Types: None designated. T y p e l o c alit y: N o l o c alit y i n di c at e d. Di a g n osis. T u b e str ai g ht t o sli g htl y c ur v e d; b as e clear, abruptly changing to obscure to which debris a d h er es. D ors al g a p i n c or o n a sli g htl y l ess t h a n n e c k wi dt h. Ventral antennae long. Dorsal nodules present (n=2). A mi cti c, male, and diapausing e mbryos undescribed. Measure ments: Tube length ~340 µ m; extended ani mal ~ 4 6 0 µ m. Co m ments. The ety mon of this genus was not discusse d by Tate m (1868). No type location is reported by Tate m (1868). Western (1891) discussed proble ms wit h Tate m’s descriptions, offering the conclusion that t h e species Tate m described was a Li mnias rather than a representative of the genus Li mnioides. Ho wever, West er n’s record of Li mnias myriophylli fro m an undefined loc ati o n i n O xs h ott, U. K. is m ost li k el y err o n e o us.

3 1 2 · Zootaxa 4442 (2) © 2018 Magnolia Press W A L L A C E E T A L. FI G U R E 3. T wo rare Li mnias species. ( A) Li mnias myriophylli. ( B) Li mnias shia wasseensis ( Line art as i n di c at e d; photo micrograph of Speci men Preparation A NSP 486 [c ollected by C.F. Rousselet] courtesy of C. Jersabek; The Acade my of N at ur al S ci e n c es of Dr e x el U ni v ersit y). S y m b ols: ct b = cl e ar t u be b as e; f = f o ot; s = s u bstr at u m; bar = 1 0 0 µ m.

Li mnias ny mphaea Stenroos, 1898 Fi g. 2 B

Li mnias melicerta ny mphae: Koste, 1978

Types: None designated. Type locality: Lake Nur mijärvi (Finland). Diagnosis. Tube dark gray, set with grains of sand. Ventral antennae short. Dorsal gap in corona unkno w n. D ors al n o d ul es pr es e nt ( n = 1 4 i n 3 r o ws: 6, 6, 2). Measure ments: Total tube length 510–650 µ m. Co m ments. The ety mon of this genus is apparently a reference to the plant substratu m, Nuphar - Blätte (si c), o n which Stenroos (1898) found speci mens. A mictic, mal e, and diapausing e mbryos undescribed. This species w as described fro m a single occurrence on the leaves of Nuphar sp. in Lake Nur mijärvi (Finland). Koste (19 7 8) st at es t h at t his s p e ci es m a y b e a f or m of L. m eli c ert a .

Li mnias s hia wassee nsis Kellicott, 1888 Fi g. 3 B

Li m ni as S hi a w asse ë nsis K elli c ott, 1 8 8 8 Li mnias shia wasseensis Kellicott: Hudson & Gosse, 1 8 8 9 Li mnias shia wasseensis Kellicott: Harring, 1913 Li m ni as m eli c ert a s hi a w ass e e nsis K elli c ott: K ost e, 1 9 7 8

3 1 4 · Zootaxa 4442 (2) © 2018 Magnolia Press W A L L A C E E T A L. Types: None designated. Type locality: Shia wassee River, Shia wassee Co., Mi c hi g a n, ( U. S. A.). Other material: Speci men Preparation A NSP 486 Diagnosis. Tube surface covered by transverse, parallel ro ws of tiny raised points. Ventral antennae l o n g. D ors al n o d ul es n = 7 i n 4 r o ws: 1 [ bif ur c at e], 2, 2, 2). D ors al g a p pr es e nt, u n d efi n e d. A mi cti c, m al e, a nd diapausing e mbryos undescribed. Measure ments: None reported. Geographic range: Very rare: Scotland ( U. K.), Flori d a, a n d Mi c hi g a n ( U. S. A.). E c ol o g y: p H, 6. 9 – 7. 6; bi c ar b o n at e, 2 1. 4 – 3 8. 4 m g/ L. Sessile on Myriophyllu m and Ranunculus . Co m ments. The ety mon of this species refers to its poorly defined type location “ … at the border of th e … ” Shia wassee River, Shia wassee Co. ( Michigan, U.S. A.). Ed mondson (1944) reported this species fro m a lak e i n Connecticut ( U.S. A.); Ahlstro m (1934) listed this s pecies as present in Florida ( U. S. A.). Additionally, t here is a m o u nt e d a d ult s p e ci m e n ( c oll e ct e d b y C. F. R o uss el et (1912.08.07), pond near Glasgo w, Scotland and prep ar e d b y L. M. D ors e y: s e e Ot h er m at eri al, a b o v e). Kellicott’s (1888) description offers ratios of certain features, but no di mensions are provided. To o ur kno wledge the seven dorsal nodules have never been ill ustr at e d a d e q u at el y. T h e or i gi n al d es cri pti o n of t his s p e ci es notes that speci mens were found attached to Myrioph yllu m along with t wo congeners L. ceratophylli and L. melicerta , both of which were more co m mon. Ed mondso n (1944) notes the occurrence of this species on hydrophytes that had the characteristics of “ … pred o minantly flat or very gently convex leaves, whether fi n el y divided or not” and certain other species that did not fit this categorization (e.g., Ranunculus ). Kellicott (1888) noted t wo interesting behaviors. (1) The ani mals ar e said to pack flocculent debris against the rugose t u b e w all. E x c e pt f or t h e pl a c e m e nt of f or m e d d e bris p ell ets i n s o m e Fl os c ul ari a a n d f e c al p ell ets i n s o m e Pt y g ur a, n o ot h er sessile species actively aug ments their tubes. (2) The coronal discs are held in a near vertical position with the v e ntr al a nt e n n a e h el d at a s h ar p a n gl e t o t h e t u b e. An additional taxon, Li mnias sphagnicola Zacharias, 1886 has not been included in the present treat ment of the genus as it is considered an unrecognizable spe cies inquirenda (Segers 2007; Jersabek & Leitner 20 1 3). I n addition the na me is included on the list of na mes to be re moved fro m zoological no menclature in the c a n di d at e p art P h yl u m R otif er a of t h e List of Av ail a bl e N a m es in Zoology (see Segers et al. 2012).

Dis c ussi o n

While the six species of Li mnias can be recognized by morphological characteristics, much of their mor p h ol o g y, lif e hist or y, a n d g e n eti cs r e m ai n u nr es ol v e d. Morphological features that need to be exa mined include the follo wing. (1) Tube : Within the t wo species gr o u ps t u b e m or p h ol o g y is disti n cti v e, wit h s o m e i nt er esti n g v ari ati o ns. I n L. m eli c ert a , t u b e l e n gt h is increased by a s eri es of dis cr et e ri n gs f or m e d b y t h e a ni m al, o n e ring on top of another ( Wright 1954; Yang & Hochb erg 2018). Except for Kutikova’s (1995) description of the earl y d e v el o p m e nt of t h e t u b e ( ≤ 7 hrs), n o d et ail e d a n al ysis of t u b e construction in me mbers of the L. ceratophylli species group has been reported. In L. shia wasseensis, t h e o ut er surface of the tube is covered with a transverse seri es of mi n ut e r ais e d a pi c es ( p oi nts) t h at b e c o m e c o at e d wit h d ar k colored debris by a curious behavior (see belo w). T he outer surface of the tube of L. ny mphaea is e mbe d d e d wit h mi n ut e p arti cl es of s a n d, b ut h o w t h at h a p p e ns h as n ot b e e n d et er mi n e d. I n s o m e f or ms, t h e t u b e is sli g htl y c ur v e d (L. melicerta ) or even t wisted (L. cornuella) (Fig. 4). (2) Corona: The presence and size of a dorsal gap in the corona has not been quantified a mong the six species. (3) Dorsal nodules : T h e n u m b er, p ositi o n, a n d s h a p e of t h e d ors al n o d ul es, as w ell as t h eir v ari a bilit y wit hi n each of the six morphospecies should be confir med. ( 4) Ve ntr al a nt e n n a e : Vari ati o n i n l e n gt h of t h e v e ntr al a nt e n n ae across species needs to be exa mined. (5) Trophi: D et ails of t h e morphology of trophi in the species co mplexes need to be exa mined using SE M technologies ( De S met 1998; Kl ei n o w et al. 1 9 9 0) i n c o m bi n ati o n wit h g e o m etri c morpho metric analyses (Fontaneto et al. 2007; Fonta n et o et al . 2004). (6) E mbryos : No infor mation regarding the size, shape, or surf ace characteristics of these e mbryos is available. (7) Larvae : N o m or p h ol o gi c al a n al ysis of t h e l ar v a e of t h e si x species has been undertaken (cf. Kutikova 1995). (8) Males : D et ails of m al e m or p h ol o g y is l a c ki n g. ( 9) Di a p a using egg: No details of the surface morphology using either light microscopy or S E M techniques are a v ail a bl e.

KE Y TO LI MNIAS Zootaxa 4442 (2) © 2018 Magnolia Press · 3 1 5 Life history features in need of resolution include t h e f oll o wi n g. ( 1) C ol o n y f or m ati o n : All or e cr uiti v e c ol o n y for mation in seen in both species groups, including for mation of both interspecific and interspecific c ol o ni es ( M e ks u w a n et al . 2 0 1 1; Wall a c e et al . 2 0 1 5), a n d is probably a function of population density ( Tiefenb acher 1972). Ho wever, we do not kno w the extent of colony for mati o n i n Li m ni as ( Fi g. 4). ( 2) S u bstr at u m s el e cti o n: W hil e s o m e species of rotifer appear to exhibit strong specifi cities for a substratu m to which larvae attach ( Wallace 1978; Wallace & Ed mondson 1986) or on which they attach t h eir e m br y os ( Wals h 1 9 8 9), w e k n o w littl e a b o ut s u bstr at a preference for any species of Li mnias. Of the six s pecies, t wo (L. ceratophylli and L. melicerta) have b e e n frequently reported to settle on a range of substrata (Francez 1984a, 1984b; Leidy 1874; Nilsen & Lari more 1973; Segers et al. 2010; Tiefenbacher 1972; Wallace 1977). Li m ni as m yri o p h ylli a n d L. s hi a w ass e e nsis e a c h h a v e b e e n reported t wice, but only on Myriophyllu m . The other t wo species, L. cornuella and L. ny mphaea, have be e n reported to occur on Trianoe Bogotensis (sic) and N uphar sp., respectively. In a 30-k m 2 lake in Thailand, Meksu wan et al. (2011) found L. ceratophylli on 10 different substrata and L. melicerta on 12. Based o n t h es e li mited records, we cannot be sure whether Li mnias species possess little preference for substrata or t h at s p e cifi cit y or l a c k of s p e cifi cit y is a n artif a ct of i nfr e q u e nt reporting. Alternatively, perceived preferences ma y be a result of identifying all speci mens only by the general morph ol o g y of t h eir t u b e: i. e., st u c c o = L. c er at o p h ylli and ringed = L. melicerta . Additionally, we do not understand th e edaphic conditions by which a substantial plankto ni c population might develop as reported for L. ceratop hylli by Beach (1960). Unfortunately, it is not cle ar whether Beach exa mined hydrophytes for sessile rotifers in that study, and the possibility of misidentificatio n is possible (see above). (3) Adult behaviors: K elli c ott ( 1 8 8 8) attri b ut e d a n u n us u al b e h a vi or t o t h e a d ults of L. s hi a w ass e e nsis: use of its dorsal processes to pack the outer surfa c e of its t u b e wit h fl o c c os e m at eri al. H u ds o n a n d G osse (1886: 76) als o r e p ort t his b e h a vi or. F e w s essil e s p e ci es ar e kno wn to exhibit a behavior that incorporates exoge n o us m at eri als into their tubes: e.g., Floscularia ringens ( Linnae us, 1758), Ptygura pilula ( Cubitt, 1872). (4) Matin g: If sexual individuals fro m various taxa were produced si multa neously, cross- mating experi ments could be perfor me d t o delineate species boundaries. ( The protocol for culturing Li mnias species described by Sar ma et al. (2 0 1 7) will b e useful.) Ho wever, cues that induce mixis are unkno w n. During four years of laboratory culture using cr o w di n g, as well as a variety of te mperature and photoperiods, we were unable to induce mixis in either L. ceratop h ylli or L. m eli c ert a ( A. K. a n d E.J. W, p ers. o bs.). Use of molecular tools has revealed hidden diversit y (cryptic species co mplexes) within many taxa of r otif er (Fontaneto 2014; Fontaneto et al. 2009) including Brachionus calyciflorus Pallas, 1766 ( Wen et al. 201 6), Brachionus plicatilis, Müller, 1786 ( Gó mez et al. 2 002; Gribble & Mark Welch 2012; Mills et al. 2017), a n d Euchlanis dilatata Ehrenberg, 1830 ( Kordbacheh et al. 2017). Although morphological differences in so m e of these taxa were recognized prior to the use of mole cular techniques, the extent of the diversity was diffi c ult t o appreciate applying morphological criteria alone (F u et al. 1 9 9 1; S e g ers 1 9 9 5). I n ot h er t a x a si mil ar di v ersit y w as suspected, which was subsequently confir med (e.g., Reyna-Fabián et al. 2010; Schröder & Walsh 2010). T o d at e these studies have included only planktonic for ms. T o a p pr e ci at e t h e e xt e nt of s essil e r otif er g e n eti c di v ersit y, w e have undertaken an analysis of cryptic species in t wo species of Li mnias, as well as other species, whi c h w e will report else where.

Ackno wledg ments

We thank H. Segers and the anony mous revie wers for their careful revie w of the manuscript. We also tha n k Michael Ple wka for allo wing us to use his photo micr ographs of Li mnias ceratophylli and L. melicerta. F u n di n g was provided by the National Science Foundation D E B-1257068 ( E.J. Walsh) and D E B-1257116 ( R.L. Wallace) and by grant 5 G12 M D007592 fro m the National Institut es o n Mi n orit y H e alt h a n d H e alt h Dis p ariti es ( NI M H D), a co mponent of the National Institutes of Health ( NI H). The content is solely the responsibility of the authors and does not necessarily represent the official vie ws of the National Institutes of Health or the National S ci e n c e Foundation.

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