Kionaster petersonae, Nauka, Paleo

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Swiss J Palaeontol (2011) 130:25–42
DOI 10.1007/s13358-010-0005-0
Kionaster petersonae, n. gen. and sp. (Asteroidea), the first fossil
occurrence of the Asterodiscididae, from the Miocene of Florida
Daniel B. Blake
•
Roger W. Portell
Received: 21 June 2010 / Accepted: 2 September 2010 / Published online: 15 December 2010
Akademie der Naturwissenschaften Schweiz (SCNAT) 2010
Abstract Kionaster petersonae, n. gen. and sp., from the
Miocene Chipola Formation of Florida, is the first-known
fossil member of the extant family Asterodiscididae Rowe.
Although abactinal and marginal expressions clearly serve
to distinguish the Asterodiscididae, the family was recog-
nized only relatively recently, in part perhaps because
assigned genera are few and these occur in traditionally
less heavily collected areas. The original inferred presence
of reduced numbers of marginal ossicles in the family is
rejected. Phylogenetic analysis suggests close affinities
between asterodiscidids and Goniaster L. Agassiz, 1836
(Goniasteridae). Kionaster appears closest to the eastern
Pacific asterodiscidids rather than Asterodiscides itself,
which is widely distributed farther west in the Pacific.
Distinctive characters of Kionaster suggest a once-greater
diversity within the family. Although data are limited,
morphologic similarities and biogeographic distributions
suggest familial origin in a low-latitude Western Hemi-
sphere setting and the Atlantic Ocean prior to the closing of
the Isthmus of Panama.
Introduction
More or less complete fossil asteroids are almost always
rare. Although dissociated ossicles are common at many
Cenozoic localities in the state of Florida, USA, very few
articulated specimens and specimen fragments have been
reported. The present paper began as a descriptive study of
a remarkable specimen of a new genus and species of the
family Astrodiscididae from the Florida Miocene (Figs.
1
,
2
). The Astrodiscididae was previously unknown from the
fossil record and the new genus is an important addition to
asteroid history. Other occurrences of Florida fossil aster-
oids were summarized by Blake and Portell (
2009
).
It was quickly realized that aspects of morphology of
asterodiscidids had to be re-evaluated before other inter-
pretive work and a formal description could be undertaken.
After consideration of the specimen and its stratigraphic
setting, morphology of the Asterodiscididae is interpreted,
followed by a phylogenetic survey of asterodiscidids and
similar valvatidan asteroids. Biogeography and functional
morphology
are
then
treated,
followed
by
systematic
Keywords Asteroidea
Asterodiscididae
Miocene
Chipola formation
Florida
treatment.
Kionaster petersonae n. gen. and sp. is assigned to the
family Asterodiscididae, which until this report was known
only from extant species. Comparatively few papers
treating asterodiscidids are available. The family was
described by Rowe (
1977
) and other papers treating
representatives include Ludwig (
1905
), Fisher (
1906
), Rowe
(
1985
), Oguro (
1991
), Liao and Clark (
1995
), and Lane and
Rowe (
2009
). Rowe (
1977
) provided a literature review.
Four extant genera have been included, Paulia Gray, 1840,
Amphiaster Verrill, 1868, Asterodiscides Clark, 1974, and
Pauliella Ludwig,
1905
. Rowe (
1977
) tentatively synony-
mized Pauliella with Paulia, and he further noted that
Ludwig himself suggested that known Pauliella specimens
D. B. Blake (
&
)
Department of Geology, University of Illinois,
Urbana 61801, USA
e-mail: dblake@uiuc.edu
R. W. Portell
Florida Museum of Natural History,
University of Florida, Gainesville 32611, USA
e-mail: portell@flmnh.ufl.edu
 26
D. B. Blake, R. W. Portell
Fig. 1 Map of Florida showing
collecting locations of
Kionaster petersonae, n. gen.
and sp.; holotype Florida
Museum of Natural History UF
148379, collected at or very
near IP CA018; paratype UF
76112, at IP CA016; paratype
UF 74923, at IP CA027. All
Calhoun County, Clarksville
Quadrangle USGS 7.5
0
, 1990;
T1N, R9W
might be only immature Paulia. Pauliella, however, is
discussed and included in the cladistic analysis here
because of the still tentative nature of the synonymy and
also because it exemplifies the goniasterid-like appearance
of immature asterodiscidids, a point made by Rowe (
1977
).
Paulia, Pauliella, and Amphiaster are only known from
their respective type species and they are restricted to the
tropical eastern Pacific (Clark
1993
). In contrast, 17 nom-
inal species have been assigned to Asterodiscides.This
genus is widespread in the tropical Indo-West Pacific, and
it extends to temperate areas of Australia and New Zea-
land. Whereas the eastern Pacific genera have been
collected from the shoreline down to 20–30 m, Asterodiscides
is most usually found within a range from 50 to 100 m,
although it has been reported from the shoreline to 792 m
(Rowe
1977
,p.215).
Phylogenetic analyses of fossil and recent asteroids,
including some similar to asterodiscidids, were under-
taken by Mah (
2005a
,
b
,
2006
,
2007
); Villier et al.
(
2004a
,
b
), and Blake (
2010
). The character suite devel-
oped for Blake (
2010
) provides the basis for treatment
here (Fig.
3
), supplemented with characters crafted for the
Asterodiscididae.
Terminology
Terminological usage largely follows Spencer and Wright
(
1966
) and Blake and Hagdorn (
2003
). Primary ossicles are
the more or less enlarged foundation ossicles of the body
wall; in contrast, accessory ossicles are the spines, spin-
elets, granules, and pedicellariae seated on primaries, these
minimally developed in Kionaster. In some asterodiscidids,
tubercles are enlarged, spine-like prominences that are a
part of the primary ossicle itself rather than an independent
accessory. A double marginal series (inferomarginals, IM,
and superomarginals, SM) arise at the unpaired terminal at
the tip of the arm and serve to separate abactinal ossicles of
the dorsal surface from the actinal ossicles developed
between the marginals and the adambulacrals. Intermargi-
nals are morphologically differentiated primary ossicles
positioned between the marginal series. A differentiated
primary circlet of abactinals is developed near the dorsal
center of the disk, and a differentiated carinal series
extends along the dorsal arm midline. The ambulacral and
adambulacral series also arise at the terminal and extend
proximally
to
the
mouth
frame
(which
is
essentially
unexposed in the Kionaster holotype).
Florida Miocene asteroid
27
an erosional remnant of the lower Miocene Torreya For-
mation (Banks and Hunter
1973
). Elsewhere, the Chipola
Formation is underlain by the upper Oligocene to lower
Miocene Chattahoochee Formation (Vokes
1989
; Huddle-
stun
1984
).
Bender (
1973
), using He/U coral dating, estimated an
average age of 16.1 (±1.0) Ma for the Chipola Formation.
Akers (
1972
), using calcareous nannofossils and planktonic
foraminifera, suggested correlation of the Chipola Forma-
tion to planktonic foraminiferal Zones N7/N8 of Blow
(
1969
), but stated a preferred placement of the unit in Zone
N7. Bryant et al. (
1992
), using 87Sr/86Sr isotope dating of
venerid bivalves, estimated an age of between 18.3 and
18.9 (±1.0) Ma. Lourens et al. (
2004
) placed the upper
boundary of the early Miocene at 15.97 Ma, well within
the error range of dates obtained by Bender (
1973
), and
assigned planktonic foraminiferal Zone N7 to the early
Miocene Burdigalian Stage (15.97–20.43 Ma). Dates pro-
vided by Bryant et al. (
1992
), although slightly older than
those suggested previously, further support a Burdigalian
age for the Chipola Formation.
Material
A single nearly complete, articulated, sand and shell debris
encrusted specimen of Kionaster petersonae n. gen. and sp.
(Figs.
4
c,
5
,
6
) was collected in June, 2008, at or very near
Chipola River locality FLMNH IP CA018, Calhoun
County, Florida, in an exposure of the lower Miocene
Chipola Formation. Intensive collecting of Chipola For-
mation outcrops over the past 100 years yielded only many
dissociated asteroid ossicles; from this suite, however, two
distinctive
superomarginals
now
can
be
assigned
to
Kionaster.
The prepared holotype is nearly fully exposed, although
the mouth frame and adambulacral series remain largely
obscured by highly resistant matrix. The holotype has arm
radii of 27 mm and disk radii of 11 mm. Overall specimen
appearance suggests only minor distortion due to sediment
compaction, and no significant decay appears to have taken
place before final burial because ossicles are little dis-
placed. Because the specimen is nearly intact, data on
internal morphology is all but unavailable, although arm
tips are variously truncated revealing distal internal ossi-
cles. The arm tips are upturned, a characteristic of many
valvatidans in life.
Because preparation techniques can be useful to others,
we include the preparator’s comments: ‘‘The preparation
was accomplished mainly using a shortened ‘stubby’ air
scribe designed for use under microscopes with a relatively
high objective magnification and short working distance.
Additionally, the rest of the mechanical preparation was
Fig. 2 Stratigraphic arrangement of units in the lower Miocene to
Pliocene Alum Bluff Group of Florida (based on Huddlestun
1984
)
Stratigraphy
Kionaster petersonae, n. gen. and sp., is based on new
material collected in the Florida Panhandle, southeastern
USA (Fig.
1
). The source horizon is the Chipola Forma-
tion, the lowermost unit of the early Miocene to Pliocene
Alum Bluff Group (Fig.
2
). Its outcrops, at Alum Bluff on
the Apalachicola River in Liberty County and along the
Chipola River and its tributaries in Calhoun County, con-
sist typically of a blue–gray to yellow–brown (deeply
weathered), unconsolidated, highly fossiliferous marl with
quartz sand. At Alum Bluff, the Chipola Formation is
unconformably overlain by Jackson Bluff Formation sedi-
ments (Huddlestun
1984
) and in subsurface is underlain by
28
D. B. Blake, R. W. Portell
Fig. 3 Phylogeny of known Asterodiscididae and selected similar
valvatidan and paxillosidan genera. Bootstrap support values
expressed as percentages. * extant genera; Calliderma is the extant
C. emma, C. is used for specimens previously assigned to Calliderma
from the collections of the Natural History Museum, London, see
Blake (
2010
); Co. Comptoniaster; N. Nymphaster; T. Tylasteria;
O. Ocalaster. For character transformations, nodes are capital letters.
Below, state changes for each nodal step are formatted ‘‘m [ n’’ and
individual characters follow, e.g., for step from node A to node B,
characters 4, 20, 64, and 87 go from 0 to 1 and 5, 43, and 52 from 1 to
0. A [ B: 0 [ 1, 4, 20, 64, 87; 1 [ 0, 5, 43, 52. B [ C:1 [ 0, 19, 49,
51; 0 [ 1, 84. C [ D: 0 [ 1, 16; 1 [ 0, 48, 81, 89. D [ E: 0 [ 1, 7,
49; 1 [ 0, 35, 90. E [ F: 0 [ 1, 17, 19, 34, 38, 44, 45, 80; 1 [ 2, 33;
1 [ 0, 39, 85, 91. F [ G: 0 [ 1, 1, 6, 14, 21; 1 [ 0, 2, 11, 15, 77;
2 [ 1, 30. G [ Kionaster:1[ 2: 1, 6, 19, 20, 30, 64; 1 [ 0, 4, 8, 17,
21, 34, 38, 47, 80; 0 [ 1, 5, 10, 22, 23, 35, 39, 43, 70, 71, 74, 75, 82;
2 [ 1, 33; 0 [ 2, 18, 59, 60, 61, 62, 63, 66, 67, 68, 69, 81. G [ H:
1 [ 0: 8, 86; 0 [ 1, 10, 22, 25, 26, 42, 43, 70, 74, 76, 82, 91; 2 [ 1,
32; 2 [ 0, 33. H [ I: 1 [ 0, 4, 17, 27, 80; 0 [ 1: 33, 51, 52, 72, 79,
83, 92. I [ J: 1 [ 0: 49, 82; 0 [ 1, 73. J [ Asterodiscides:0[ 1: 4,
17, 55, 58, 80. J [ K: 0 [ 1, 3; 1 [ 0, 22, 33. K [ Paulia:no
character transformation. K [ Pauliella:1[ 0, 51, 52, 72.
I [ Amphiaster:0[ 1, 5, 24. H [ Goniaster:1[ 0: 19, 34; 0 [ 1,
35, 55, 58. F [ Pentagonaster:0[ 1, 1, 3, 6, 12, 14, 21, 63; 1 [ 0, 2,
4, 11, 13, 15, 49, 77; 2 [ 1, 30; 1 [ 2, 31. E [ Mediaster:0[ 1, 17,
19, 26, 34, 38, 42, 43, 44, 45, 48, 80; 1 [ 2, 33; 1 [ 0, 39, 85, 91.
D [ L: 0 [ 1: 7, 12, 14, 49; 1 [ 0, 13, 35, 84, 90. L [ M: 0 [ 1, 3,
17, 43, 78, 79; 1 [ 0, 8, 15. M [ N: 1 [ 0, 20, 47; 1 [ 2, 33; 0 [ 1,
42, 53, 58, 63, 67, 80, 88. N [ O: 0 [ 1, 66, 68, 69. O [ P: 0 [ 1, 8,
35, 56; 2 [ 1, 33; 1 [ 0, 42, 43. P [ Co.adamsi:0[ 1, 1, 19, 45, 48;
1 [ 0, 2, 58, 88. P [ Co.comptoni:0[ 1, 29, 54, 57; 1 [ 0, 49.
O [ Q: 0 [ 1, 44, 46, 65; 1 [ 0, 53, 78, 79, 80. Q [ N.ornatus:
0 [ 1, 10, 19, 28, 37, 48, 60, 62, 84; 1 [ 2, 31. Q [ Ogmaster:1[ 0,
3, 39, 58, 85; 0 [ 1, 4, 9, 36, 38, 50, 89; 0 [ 2, 6; 2 [ 1, 32.
N [ Ophyraster:1[ 0, 3, 39, 49, 77; 0 [ 1, 4, 10, 34, 38, 55, 89;
1 [ 2, 31, 88. M [ R: 0 [ 1, 36, 50, 84. R [ S: 1 [ 0, 17, 39;
0 [ 1,40, 46. S [ T: 0 [ 1: 10; 1 [ 0, 43, 50, 78, 79. T [ ‘‘ C.’’smit-
hae:1[ 0, 27, 47; 0 [ 1, 29, 44, 60, 62, 65; 1 [ 2, 33. T [ U, 1 [ 0,
20, 31, 49, 0 [ 2, 88. U [ Calliderma:1[ 0, 3, 64, 84, 85; 0 [ 1, 4,
13, 51. U [ N.arenatus:1[ 0: 11, 33, 77; 0 [ 1, 26, 48, 63, 80 89,
90. S [ Oyenaster:0[ 1, 1, 4, 8, 48, 81; 1 [ 0, 2, 3, 77.
R [ O.timucum:1[ 2, 16; 0 [ 1, 19, 52. L [ V: 1 [ 0, 11, 64;
1 [ 2, 16. V [ T.berthandi:1[ 2, 33; 0 [ 1, 4, 34, 38, 48; 1 [ 0,
39. V [ Noviaster:0[ 1, 5, 35. C [ Co.basseti:0[ 1, 1, 9, 16, 78,
79, 88; 1 [ 0, 2, 8, 48, 77, 81. B [ Radiaster:0[ 1, 18, 59, 61, 84;
1 [ 0: 19, 35, 39, 47, 49, 51, 86, 89, 91; 2 [ 1, 30, 32. A [ W: 0 [ 1,
4, 20, 60, 62, 64; 1 [ 0, 5, 43, 52; 1 [ 2, 31, 33, 48. W [ Pseud-
archaster:0[ 1, 7, 17, 78, 87; 1 [ 0, 49, 77, 91. W [ Plutonaster:
1 [ 0, 19, 39; 0 [ 1, 38, 42, 79, 80, 88
accomplished through the use of very fine tungsten carbide
needles in a pin vise. The matrix, silica sand with numerous
foraminifera microfossils bound by calcareous cement was
very hard and due to its coloration was difficult to distin-
guish from the ossicles of the sea star. The separation of the
matrix from the specimen was hindered by the fact that
slight recrystalization of the ossicles had tightly bound the
matrix to existing anatomy. In some cases the ossicles
which had been partly exposed due to weathering were
hollow. This was due to the action, presumably, of plant
roots and these voids had to be filled with Polyvinyl But-
eral B-76 to prevent their collapse. Forams in particular
looked dauntingly like small ossicles and had to be exposed
and removed on a case by case basis. Work with the air
scribe was facilitated by removing the matrix down to
within a fraction of a millimeter of the sea star’s surface. At
this point if the matrix was wetted the ossicles would show
clearly
through
the
transparent
sand
grains.
On
larger
Florida Miocene asteroid
29
Fig. 4 Arrangement of marginals and related ossicles. Scale bars, a,
d–h 5 mm; b, c, i–k 10 mm. a, b, Goniaster tessellatus (Lamarck
1816), USNM Division Echinoderms E06716, a, uncleared arm and
interbrachium, marginals edged by granules, superomarginals bear
tubercles, abactinals with spines; b, interbrachial arc, granules
cleared, intermarginals (arrows); c, Kionaster petersonae n. gen.,
holotype, UF 148379, interbrachium, tubercles forming prominences;
d, e, Paulia horrida Gray, 1840, USNM Div. Ech. 38087, partially
cleared; d, distal lateral view of arm and interbrachium shows both
larger and smaller marginals, IM ossicles more numerous, interca-
lated intermarginals, a few granules remain; e, dorsal–lateral with
enlarged distal SM ossicles; f, Amphiaster insignis Verrill, 1868,
USNM Div. Ech. 39862, partially cleared; lateral view of arm and
interbrachium, marginal ossicles are robust and closely spaced, some
granules remain; g, Pauliella aenigma Ludwig
1905
, USNM Div.
Ech. 102006, lateral view of disk and interbrachium, marginal
ossicles are robust and closely spaced, granules obscure ossicular
boundaries; h–k, Asterodiscides truncatus (Coleman, 1911), USNM
Div. Ech. E10144, partially cleared arm, h, arrow identifies row of
marginals below enlarged distal SM, i, k, arrows identify two
marginals from different perspectives; dark boundary above margin-
als is the edge of the abactinal papulate field, see text for discussion
ossicles, air scribing would resume after wetting. The
transparency would immediately disappear through drying
and work would proceed by memory until a slight
texture change or nervous discomfort would indicate that
re-wetting the specimen was necessary. For smaller ossi-
cles preparation was done entirely while the specimen was
wet using carbide needles 1/32 of an inch thick. Total prep
time
Aspects of morphology of the Asterodiscididae
The Asterodiscididae was recognized only relatively
recently for three extant genera and because few specimens
were available to its author, Rowe (
1977
, p. 211) expressed
uncertainty as to the status of Pauliella (as noted above)
and also as to whether Paulia and Amphiaster should be
separated. The original diagnosis of the family was
detailed, reflecting both the morphologic complexity of the
took
an
estimated
270 h.’’
(Matt
Smith
personal
commun. to RWP, May 2010).
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