Minibiotus constellatus, a new species of Tardigrada from Peru (Eutardigrada : Macrobiotidae)

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M inibiotus constellatus, a new species o f Tardigrada from Peru (Eutardigrada: M acrobiotidae)

Łu k a s z Mi c h a l c z y k1 and Łu k a s z Ka c z m a r e k2

i n s t i t u t e o f E n v iro n m en tal S cien ces, Ja g iello n ian U n iv e rsity , In g ard e n a 6, 3 0-060 K raków , P o lan d , e-m ail: ag n o stic @ p o c zta.fm

2D ep artm en t o f A n im al T ax o n o m y an d E co lo g y , A . M ic k ie w icz U n iv e rsity , S zam arzew sk ieg o 91a, 6 0-569 P o zn ań , P o lan d , e-m ail: l_ k a c z m a re k @ w p .p l;

Ab s t r a c t. A n ew e u tard ig rad e , M in ib io tu s co n stella tu s n. sp. is d escrib ed fro m sam ples o f m o ss c o lle c te d in P eru . T his species is sim ilar to M in ib io tu s sid e re u s Pi l a t o

et al., 2003 in h av in g larg e sta r-sh ap e d , as w e ll as sm all ro u n d p o res o v er th e cuticle.

N e v e rth e le ss, M. co n stella tu s n. sp. d iffers fro m M. sid e reu s in h av in g th in n e r lateral th ic k e n in g s in th e b u c c a l tu b e, th e p re se n c e o f five p o res aro u n d the m o u th an d fine g ran u latio n aro u n d the claw s o f at least II-IV p airs o f legs.

K e y w o rd s: tax o n o m y , T ard ig rad a, E u ta rd ig ra d a , M a cro b io tid ae, new sp ecies, M in ib io tu s co n stella tu s, S outh A m erica, P eru

Until now 25 species o f the genus Minibiotus are known (Bi n d a & Pi l a t o 1995 a, b, Cl a x t o n 1998, Pi a l t o et al. 2003). In this paper Minibiotus constellatus n. sp.

is described and figured.

All measurements are given in micrometers [pm]. Body length was measured from the mouth to the end o f the body, not including the hind legs. Buccal tube length and level of the stylet support insertion point were measured according to Ki n c h i n 1996. Buccal tube widths were measured as the internal diameters at the level o f the stylet support insertion point (in all specimens buccal tube walls were 0.5 pm thick). Lengths of claws were measured from the base o f the claw to the top o f the primary branch, including accessory points. The p t ratio is the ratio o f the length o f a given structure to the length of the buccal tube expressed as a percentage (Pi l a t o 1981). In the description o f the holotype, the p t is given after

pm value [in brackets and in italics].

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296 Ł U K A S Z M IC H A L C Z Y K , Ł U K A S Z K A C Z M A R E K

Photos were made with use o f Phase Contrast Microscope (PCM), Nomarski Differential Interference Contrast Microscope (DIC) and Scanning Electron M i

croscope (SEM). All drawings were made with use o f camera lucida associated with PCM.

Twenty-six specimens were found in moss samples from Huaras, Western Peru; 24 o f these were mounted on microscopic slides in H oyer’s medium and two were prepared to SEM. No eggs were found.

Minibiotus constellatus n. sp.

Et y m o l o g y

The name “constellatus” refers to the ‘constellations’ o f star-shaped pores on the cuticle o f the animal.

De s c r i p t i o n

Description of holotype: Body length 259.4 (Figs 1-10). Body white or transparent. Eye spots absent. Cuticle with small (0.5-1.0 in diameter) round pores and larger (1.0-3.5 in diameter) star-shaped pores (‘stars’) with thickened rims (Figs 1-10, 11-14). ‘Stars’ with 3-7 arms, however with 4 -6 most common.

Number o f ‘stars’ with higher number o f arms rises on caudal part o f body. ‘Stars’

may seem to be distributed randomly, but two rows, arranged along main axis o f body, are visible on the dorsal cuticle (Fig. 3). Sometimes also present (but not numerous) irregular pores (approximately 2 in diameter) whose look like undevel

oped ‘stars’. Small round pores distributed randomly and with relative high density (Figs 4, 6). All types of pores present over whole cuticle, but with higher density on its dorso-lateral part. Ring o f five, round or oval pores present around mouth, below sensory fields (pores: 3 in diameter) (Figs 15-16). Soft, conical spines on body and peribuccal papillae absent. Ten peribucal papulae present, mouth antero-ventral. Buccal tube 29.5 long and 1.0 [3.2] wide, with two bends (Fig. 16). Stylet supports inserted on buccal tube at 17.6 [59.7]. Apophyses in pharynx triangular, very near first macroplacoid. First macroplacoid largest, pear

shaped, (2.6 [6.6] long), second smaller, round (2.2 [7.5] long) and third, smallest, round (1.9 [6.5] long). M acroplacoid row 8.5 [29.9] long. D istinct round microplacoid 1.0 [3.2] long. Pharyngeal bulb slightly oval, 28.5 long and 26.6 wide [96.8 x 90.3] (Fig. 15-16). Claws short and robust. Fine granulation on all legs. Granulation better developed on IV pair o f legs, on legs I-III aranged in small patches on outside o f leg, above claws, not well visible even with highest m agnifi

cation. Primary branch with basal claw o f fourth pair o f legs 7.6 [25.8] long, secondary branch 4.8 [16.1] long. Primary branches o f internal and external claws with two distinct accessory points. All claws with smooth-edged lunules, better developed on IV pair o f legs (Figs. 17-20).

Remarks: Results o f simple statistical analysis o f measurements and p t values o f selected morphological structures for all specimens are given in Tables 1-2.

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Three specimens (13%) have eyes. Six specimens (25%) have granulation only on II-IV pair o f legs.

T ab le 1. M e asu rem en ts [in pm ] o f se le c te d m o rp h o lo g ic a l stru ctu res o f sp e cim en s o f M in ib io tu s co n stella tu s n. sp. m o u n ted in H o y e r’s m edium .

CHARACTER MIN MAX MEAN SD N

Body length 198.0 314.5 255.76 29.02 24

Buccal tube length 22.8 30.4 26.43 1.68 20

Level of the stylet support insertion

point 14.3 17.6 16.10 0.87 20

Macroplacoid 1 length 1.9 2.9 2.43 0.31 20

Macroplacoid row length 6.7 8.6 7.71 0.51 20

Microplacoid length 1.0 1.4 0.98 0.11 20

Buccal tube internal width 1.0 1.4 1.00 0.14 20

Primary branch of claw I length 3.8 6.7 5.70 0.70 24

Secondary branch of claw I length 3.3 5.7 4.36 0.60 24

Primary branch of claw II length 4.8 7.6 5.99 0.71 24

Secondary branch of claw II length 3.8 5.7 4.52 0.64 24

Primary branch of claw III length 4.8 7.1 6.15 0.58 24

Secondary branch of claw III length 3.8 5.7 4.44 0.55 24

Primary branch of claw IV length 5.7 8.6 7.54 0.75 23

Secondary branch of claw IV length 3.8 7.1 5.57 0.83 23

T able 2. T he p t v alu es o f sp e cim en s an d se le c te d m o rp h o lo g ic a l stru ctu res o f M in ib io tu s co n stella tu s n. sp. m o u n te d in H o y er’s m edium .

CHARACTER MIN MAX MEAN SD N

Body length 771.9 1187.5 960.98 109.81 20

Level of the stylet support insertion

point 57.7 66.7 60.99 2.41 20

Macroplacoid row length 25.0 35.4 29.19 2.20 20

Microplacoid length 3.1 5.2 3.73 0.42 20

Buccal tube internal width 3.1 5.4 3.82 0.56 20

Primary branch of claw I length 15.4 25.9 21.58 2.69 20

Secondary branch of claw I length 12.9 21.4 16.57 2.25 20

Primary branch of claw II length 18.5 29.6 22.48 2.63 20

Secondary branch of claw II length 14.3 22.2 16.98 2.08 20

Primary branch of claw III length 17.2 27.8 23.04 2.10 20

Secondary branch of claw III length 13.8 20.8 16.48 1.98 20

Primary branch of claw IV length 22.2 34.6 28.71 2.86 19

Secondary branch of claw IV length 14.8 25.9 20.95 3.33 19

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Ty p e Ma t e r i a l

Holotype and 25 paratypes: Western Peru: near Huaras, elevation approxi

mately 4000 m, V. 2002, mosses from rocks, leg. An i b a l Ca n c h a y a.

The holotype is preserved at the Zoological Museum o f Jagiellonian Universty, ul. Ingardena 6, 30-060 Kraków, Poland; 11 paratypes are preserved in the collection o f £. Mi c h a l c z y k (Jagiellonian University); 11 paratypes are preserved at the Department of Animal Taxonomy and Ecology, A. Mickiewicz University, Poznań; 2 paratypes are preserved in collection o f Sa n d r a K. Cl a x t o n of Macquarie University, Australia.

Di f f e r e n t i a l D i a g n o s i s

Since the acceptance o f this paper, Pi l a t o et al., 2003 have described very sim ilar species M inibiotus sidereus. This species differs from M inibiotus constellatus n. sp. by following characters: absence o f five pores in ring around the mouth, presence o f granulation only on the last pair of legs, presence o f much thicker lateral thickenings in caudal portion o f the buccal tube and slightly longer claws. Moreover, in M. constellatus n. sp. the third macroplacoid is the shortest (length order of macroplacoids: 1-2-3) and in M. sidereus the shortest macroplacoid is the second one (length order o f macroplacoids: 1-3-2). In all paratypes o f M. sidereus eyes are present, in the population o f M. constellatus n. sp. that we have found only 13% o f individuals have eyes.

M. constellatus n. sp. is also similar to Minibiotus aculeatus (Mu r r a y, 1910) but clearly different from it because of the absence o f soft triangular spines on dorsal cuticle (Fig. 21) and the presence o f granulation on, at least, the last three pairs o f legs. Moreover, M. aculeatus has ten pores in ring around the mouth (Cl a x t o n 1998).

Ac k n o w l e d g e m e n t s

The authors wish to thank An i b a l Ca n c h a y a who collected the moss samples and Sa n d r a K. Cl a x t o n o f Macquarie University (Australia) for providing speci

mens o f M. aculeatus and for her valuable comments on the manuscript. We are also grateful for comments on the m anuscript by Dr. W. Ma g o w s k i and Ms. A. Sk o r a c k a o f A. Mickiewicz University (Poland). This work w ouldn’t have been possible without the use of equipment which was been made available to us courtesy o f Pr o f. d r. h a b. S. Bi l i ń s k i, Dr. h a b. J. Ra d w a n, Dr. h a b. A. Ja n k u n and Dr. M. Wa y d a o f the Jagiellonian University (Poland). And last but not the least many thanks for Pr o f. d r. h a b. B. Wę g l a r s k a o f Jagiellonian University (Poland) for her continuous general support.

R E F E R E N C E S

Bi n d a, M . G. & Pi l a t o, G ., 1995a. R em ark s on ta rd ig ra d e s fro m th e S ey ch elles, w ith a d escrip tio n o f tw o new species. T ro p ic a l Z oo lo g y . 8: 1-6.

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— , 1995b. Som e n o te s on A frica n ta rd ig ra d e s w ith d escrip tio n s o f tw o new species. T ro p ical Z o o lo g y . 8: 367-372.

Cl a x t o n, S. K ., 1998. A R e v isio n o f the G enus M in ib io tu s (T ard ig ra d a: M a c ro b io tid a e ) w ith D escrip tio n s o f E leven N ew S p ecies fro m A u stralia. R e co rd s o f A u stra lia n M u seu m . 50: 125

160.

Ki n c h i n, I. M ., 1996 M o rp h o m e tric a n a ly s is o f R a m a z z o ttiu s v a r ie o r n a tu s ( H y p s y b iid a e : E u trad ig rad a). Z o o lo g ic a l Jo u rn al o f th e L in n e an Society. 116: 51-60.

Pi l a t o, G ., 1981. A n alisi di n u o v i cara tte ri n e llo studio d eg li eu ta rd ig ra d i. A n im alia. 8: 51-57.

Pi l a t o, G ., Bi n d a, M . G ., Li s i, O ., 2003. R em arks on som e species o f ta rd ig ra d e s fro m South A m e ric a w ith th e d e sc rip tio n o f M in ib io tu s sid e re u s n. sp. Z o o ta x a , 195: 1-8.

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1-2. M in ib io tu s co n stella tu s n. sp., h a b itu s: 1 - d o rsal v iew , 2 - v e n tra l view

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3-4. M. c o n ste lla tu s n. sp., p a tte rn s o f p o re s on cu ticle w ith sm all ro u n d p o res e rase d to give clearer v iew o f th e p attern o f sta r-sh a p e d a n d irre g u la r p ores: 3 - d o rsa l cu ticle, 4 - v e n tra l cu ticle

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5-6. M. co n stella tu s n. sp., p a tte rn s o f po res on cu ticle w ith sta r-sh a p e d an d irre g u la r p o re s e rase d to give c learer v ie w o f th e p a tte rn o f sm all ro u n d p ores: 5 - d o rsa l c u ticle, 6 - v e n tra l cu ticle

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7-8. M. co n stella tu s n. sp., h a b itu s: 7 - d o rsa l v iew , 8 - la te ra l v iew (S E M ), 9 - d o rso -la te ra l view , 10 - v e n tro -la te ra l v iew (D IC )

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11-14. M. c o n stella tu s n. sp., ty p e s o f sta r-sh ap e d p o re s on d o rsal cuticle: 11 - w ith fo u r arm s, 12

13 - w ith five arm s, 14 - w ith six arm s (SE M ) (n o te also p resen c e o f sm all ro u n d po res); 15-16.

b u c c a l ap aratu s: 14 - v e n tra l v iew (n o te also a rin g o f five p o re s aro u n d m o u th o p en in g ), 15 - lateral v iew (n o te th e tw o b en d s o f b u c c a l tu b e (w h ite arro w s), one o f five p o res su rro u n d in g m o u th op en in g

(b la c k arro w ), an d an te ro -v e n tra l p la c e d m o u th o p en in g ) (PC M )

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17-20. M. co n ste lla tu s n. sp., claw s o f IV p a ir o f legs: 17 - d raw n in g , 18 - D IC , 19-20 - SEM (“ e”

= ex te rn a l claw ; “ i” = in te rn a l claw ; = cu ticle above c law s w ith fin e g ran u latio n ); 21. M in ib io tu s a cu lea tu s (Mu r r a y, 1910), cau d al p a rt o f b o d y w ith th ree p airs o f soft sp in es (w h ite arro w s) above

II, III an d IV p a ir o f legs (PC M ; sp ecim en fro m A u stralia)