Henricia pumila sp. nov.: A brooding seastar (Asteroidea) from the coastal northeastern Pacific
Author
Eernisse, Douglas J.
Author
Strathmann, Megumi F.
Author
Strathmann, Richard R.
text
Zootaxa
2010
2329
22
36
journal article
10.5281/zenodo.275445
406e7277-8fee-473b-98b5-3a881decf7db
1175-5326
275445
Henricia leviuscula
(
Stimpson 1857
)
Figs. 2
A–E, 3A, 4A, 5A, 5C, 5E
Type
:
USNM
0 3357 (
holotype
)
Type
Locality: Puget Sound, Washington,
USA
Linckia leviuscula
Stimpson, 1857
: 529
.
?
Cribrella leviuscula
(Stimpson)
,
Cribrella laeviuscula
(Stimpson)
, or
Henricia leviuscula
(Stimpson)
: Numerous authors reviewed by
Fisher, 1911
and by
A. Clark, 1996
.
Henricia leviuscula
(
Stimpson 1857
)
: in part
Fisher, 1910
: 570
; in part
Verrill, 1914
: 215
; in part
Djakonov 1961
:23
, Pl. II, fig 9; in part
Lambert, 1981
: 100
–103; 2000: 104–106.
Henricia leviuscula
“var. A after Fisher”:
Djakonov 1950
: 95
, f. 79, 80
Henricia leviuscula
var. B: in part
Fisher 1911
: 280
–291, pl. 70, f. 2, pl. 111, f. 6
Henricia leviuscula
var.
leviuscula
: in part
Verrill 1914
: 217
, pl. XII–f. 5, pl. XIII, f. 1–2.
Henricia leviuscula
var.
lunula
: in part
Verrill 1914
: 219
Type
material examined:
A specimen (
Fig. 2
A–E) originally labeled only “
Henricia leviuscula
, Id. W.K. Fisher, Ft. Steilacoom
[near Tacoma, Pierce Co., Washington; 47°10.80΄N 122°35.42΄W], Pudget [sic] Sound, Dr. Geo. Suckley Col.” matched Stimpson’s brief published locality: “Found in Puget Sound, by Dr. Suckley.” Our analysis revealed this specimen to be the likely
holotype
and it has since been labeled as such in the
USNM
collection.
Other material examined:
more than
40 specimens
in our collections from the San Juan Archipelago, including
USNM
1116587 (
Figs. 3
A, 4A, 5C, 5E), Cattle Pt., San Juan Id., San Juan Co., Washington, intertidal, and
MFS
149 (
Fig. 5A
), and two from Lovit Island, British
Columbia
. Museum specimens identified included:
USNM
5991 (Baranoff Id., Alaska,
18m
);
USNM
3386 and 9225 (Puget Sound);
USNM
E4679 (“probably Alaska”);
USNM
E8678 (Departure Bay, British
Columbia
);
USNM
E3780 (Mouth of Strait of Juan de Fuca,
73 m
);
USNM
E3820 (Port Townsend, Washington,
27–48 m
);
CASIZ
0 0 8559 (1 of 9 previously designated as vouchers for
Henricia leviuscula
by
Fisher (1911:281–282, 285))
;
CASIZ
112955
(Anchor Pt., Kenai Peninsula, Alaska);
CASIZ
180558
(San Juan Channel off Lopez Id., San Juan Co., Washington, 100–110);
LACM
1959-281.3 (Monterey, California);
LACM
1966-36.16 (lot of 2, off Cowichan, Sydney Channel, British
Columbia
18–37 m
);
LACM
1966-37.19 (lot of 2, Sister’s Rocks, outer Squamish Harbor, Hood Canal, Washington, intertidal);
LACM
1966.39.23 (lot of 2, MacKaye Harbor, Lopez Id., Washington, intertidal);
YPM
9836 (1 of 2
syntypes
for
Henricia leviuscula
(Stimpson)
var.
lunula
Verrill, 1914
, Victoria, British
Columbia
,
Canada
,
20m
).
Description:
Most specimens have 5 slender rays, but 6-rayed individuals occur. Slender rays are without basal swelling and taper evenly to the ray tip. The dried
holotype
has 5 slender rays, not basally swollen, with R about
35 mm
and r about
6.3 mm
, R/r = 5.6 (
Fig. 2
A–E). Of
42 specimens
from the San Juan Archipelago and 2 from Lovit Id., British
Columbia
, the largest had R =
70 mm
, r =
10 mm
and the smallest, R =
22 mm
, r = 4.0 mm. The range of R/r was 5.0 to 8.3.
The aboral color in living specimens is distinctive bright orange, sometimes slightly red-orange (
Fig. 3
A), with the color characteristically continuing onto the oral surface, fading to light orange or yellow sometimes over the ventrolateral plates but most usually on only the adambulacral plates.
The aboral surface appears smoothly and regularly paved or scaled, this surface being composed of closeset pseudopaxillae with narrow intervening spaces and small recessed papular areas. In outline the pseudopaxillae are oblong or irregularly polygonal on the disc and oval, crescentic, heart-shaped, or triangular on the rays, with the concave or flat side toward the disc (
Fig. 2
B, 2D, 4A, 5C, 5E). The madreporite is not particularly prominent and bears single rows of spines that are like those on the pseudopaxillae.
Aboral papular areas have 1, sometimes 2, rarely 3 papulae. A regular series of single papulae occurs on the oral surface between the inferomarginal and ventrolateral plates on the disc and most of the ray length. A few single papulae may occur in an irregular series between some ventrolateral and adambulacral plates.
Aboral pseudopaxillae are composed of spines set in tissue-covered, close-packed, upright arrays of 20 to 100, but usually 25 to 55 (
Fig. 5
C, 5E). In living specimens the pseudopaxillae are covered by pigmented tissue through which some of the radiating glassy thorny tips of the spines might just be discerned. The aboral spines are stout with fenestrated glassy shafts, commonly 80 to 100 µm in diameter, with smooth sides. The ends of the spines have 3 to 7 heavy thorn-like points or tips (as noted by
Djakonov 1961
), of about equal sizes that flare in a fairly even radiating pattern that spans 100 to 190 µm (
Figs. 2
D, 5A, 5C, 5E). A large spine on the
holotype
is about 220 µm long, has a shaft about 70 µm in diameter, and ends in prominent sharp points radiating over a span up to 165 µm.
Ray sides have the lowermost dorsolateral pseudopaxillae in approximate 1:1 alignment with the superomarginal pseudopaxillae (plates) below them, but in offset alignment with the pseudopaxillae above them. Superomarginal pseudopaxillae are larger than the dorsolaterals, sometimes as much as twice the size.
Ray lower sides have three conspicuous series of pseudopaxillae: rectangular superomarginals and inferomarginals and smaller, squarish ventrolaterals. These series of pseudopaxillae are aligned in 1:1 correspondence beside the adambulacral plates for most of the ray length. The superomarginal series descends abruptly in the interradial area to lie adjacent to the inferomarginal series, enclosing a very small interradial triangle of only a few intermediate plates and, as
Hayashi (1940)
noted, there are no secondary ventrolaterals, singly or in series. The ventrolateral series usually extends most of the ray length, but sometimes only half. Among
21 specimens
, the ratio of ventrolateral to adambulacral plates (V/A, counted from mouth to ray tip) ranged from 0.43 to 0.85 but only
2 specimens
had ratios of 0.5 or lower.
FIGURE 2.
Henricia leviuscula
holotype USNM 0 3357, dry. A. aboral and oral views, scale bar = 10 mm. Note slender rays and small disc. Two ray tips are broken. B–C. ray base to mid-ray, scale bar = 2 mm. B. aboral surface. Note closeset aboral pseudopaxillae and small papular areas. C. oral surface. Note 1:1 correspondence of adambulacral, ventrolateral, and, partially in view, inferomarginal plates covered with spines. D–E. ray base at higher magnification, scale bar = 0.5 mm. D. aboral pseudopaxillae. Note glassy spines with smooth-sided shafts and splayed points. E. oral view showing three sets of adambulacral, ventrolateral, and inferomarginal plates, with adambulacral furrow to the left. Adambulacral plates bear 1 deep furrow spine and 13 to 14 spines of diminishing size. Adjacent ventrolateral plates bear about 15 smaller spines. Inferomarginal plates (not in focus) are elongated and more spinous. Superomarginal plates, which lie aboral to the inferomarginals, are not in view.
Near the base of the ray, a superomarginal pseudopaxilla bears 25 to 100 spines; an inferomarginal, 32 to 100 spines; and a ventrolateral, 5 to 20 spines. The spine count varies among individuals and is not correlated with body size. Each adambulacral plate (
Fig. 2
C, 2E) bears 1 thin curved deep-furrow spine and 8 to 17 large, slightly curved, columnar spines in a zigzag or double row that becomes a triple or quadruple row on the edge farthest from the ambulacral furrow. The larger spines near the furrow are blunt-ended with finely spinous surfaces; those farther from the furrow are smaller and more coarsely spinous with sharp terminal points but not radiating thorns. On the
holotype
, the largest adambulacral spine is about 175 µm in diameter and 775 µm long.
Distribution:
H. leviuscula
, as restricted herein, has a confirmed range limited to southern Alaska (Kenai Pt.) south to Puget Sound (see Remarks). In the San Juan Archipelago it is uncommon in rocky intertidal areas but occurs more often in shallow subtidal areas. Many of the museum specimens whose identity we have confirmed are from the San Juan Archipelago, northern Puget Sound, or Vancouver Island.
Reproduction.
We assume that sexes are separate. When specimens of
H. leviuscula
, or one of a number of similar co-occurring species, have been spawned in isolation, eggs have not been observed to develop. Spawned eggs have been measured at 1342 µm diameter (
Strathmann
et al.
, 2002
), and we confirmed that one female induced to spawn released slightly ovoid red-brown eggs 1.45 x
1.16 mm
in diameter. Spawning individuals have been seen with the disc elevated to shed sperm or eggs freely into the water through aboral gonopores (
Strathmann, 1987
). Spawning season, like that of congeners with pelagic development, is probably early spring in the San Juan Archipelago. Development is similar to that described for other
Henricia
species (
Masterman 1902
,
Strathmann 1987
,
Komatsu
et al.
1995
). Embryonic stages do not adhere to one another but float freely. Post-hatching larvae are ciliated and swim. Future reproductive observations need to be considered with respect to knowledge of multiple
H. leviuscula
-like species, but no one has ever reported feeding in any
Henricia
larva. This and the large size of their yolky eggs implies that larvae of
H. leviuscula
are lecithotrophic. However, the possibility that
Henricia
larvae might uptake dissolved organic matter has not been tested and no one has sectioned
Henricia
larvae to see if some might have an open mouth. The brachiolar larva has an anterior lobe with three brachiolar arms surrounding an adhesive disc and late in development has five groups of podia protruding on the left side. Metamorphosis begins after about 30 to 40 days; the anterior lobe is resorbed into the oral edge of the disc.
Remarks.
We discovered a dried specimen in the USNM collections that matches the published record and we consider it to be the
holotype
. This specimen may be the one
Fisher (1911: 284)
wrote of as “perhaps the
type
; if not, it is at least a topotype.” In describing a multi-species collection from Puget Sound made by N. R. Harrington from
Columbia
University in
1896 and 1897
,
H. L. Clark (1901)
introduced two nominal varieties for Stimpson’s
leviuscula
(as “
laeviuscula
”):
crassa
and
attenuata
. He provided only a brief diagnosis for each involving a ratio of the distance from the disc center to either the ray tip (R) or the disc edge between rays (r). R/r ranged from 2.0 to 3.5, n = 25 for
crassa
vs. R/r = 5.0, n = 1 for
attenuata
. We have been unable to locate Clark’s
type
material at either the American Museum of Natural History (affiliated with
Columbia
University) or MCZ (where Clark later worked). Given the insufficient nature of Clark’s characterization and the absence of known
type
material, we consider these nominal varieties as
nomen
dubia
. Verrill’s (1914) description of the color of
H. leviuscula
var.
attenuata
(
Clark 1901
)
as “orange and orange-red above, yellow below” does not apply to
H. leviuscula
as restricted herein.
We consider Fisher's
H. leviuscula
variety B to correspond in part to
H. leviuscula
based on his statement (1911:281) that variety B is typical of the “littoral form from Puget Sound with very regular marginal plates, eight to fifteen adambulacral spinelets, and the abactinal spinelets ending in numerous sharp denticulations rather than in a solid glassy tip.” He had examined “a specimen evidently labeled by Stimpson,” and wrote that “the
type
is therefore one of the various forms of variety B, among those listed herewith.” His photographs (
Fisher, 1911
: pl. 70, fig. b, c) are not at high enough magnification to show the form of the “sharp denticulations” of the aboral spines. Nothing in his description of variety B is incompatible with
H. leviuscula
, but his variety B may include at least one other sympatric species that has subtly different spines. We re-examined many museum specimens identified as
H. leviuscula
by Fisher and found that most lack the characteristic aboral spines exhibited by the
holotype
and belong instead to other species, some of which are likely undescribed. We believe that most reports of
H. leviuscula
from the North Pacific refer to other similar species. Fisher's
H. leviuscula
varieties A and C to F are probably all other species, some of which will be assessed in a regional revision of the genus (D. Eernisse and M. Strathmann, in prep.).
Verrill's (1914) eight varieties and one subspecies of
leviuscula
are mostly other species. We were able examine the only two known
syntypes
of
H. leviuscula
(
Stimpson, 1857
)
var.
lunula
Verrill, 1914
and have tentatively identified one of these (YPM 9836), from Victoria, Vancouver Island, as
H. leviuscula
. We designate YPM 9836 as a
paralectotype
of
H. leviuscula
. We designate the other
syntype
(YPM 9835) as
lectotype
of
lunula
because this is clearly the only specimen figured and the only
lunula
“
type
” mentioned by Verrill. The aboral plates denuded of spines accord with his figures 2a–b (Plate 88) and the specimen is from Monterey, California, as stated by Verrill in reference to the figured specimen (p. 218); however, it is unclear whether he considered both specimens in the lot as “
types
” or only the figured specimen as
holotype
in a modern sense. Given the uncertainty, a
lectotype
designation is appropriate but the
lectotype
is not
H. leviuscula
and will be treated in a subsequent study (D. Eernisse and M. Strathmann, in prep.).
Djakonov (1950: 95)
distinguished two varieties of
H. leviuscula
based on form of aboral spines. The aboral spines he described for
H. leviuscula
variety A, as “low with sharp but coarse glassy spines protruding on various sides as found in a specimen from Nanaimo Bay” (
Djakonov 1950: figs. 79, 80
), corresponds to the spine morphology we found on the rediscovered
holotype
. We have not seen any specimens studied by Djakonov but his
H. leviuscula
variety A could be
H. leviuscula
. It should be noted, however, that Djakonov's variety A is not equivalent to Fisher's variety A, which had aboral spines ending in a solid glassy tip. Djakonov's
H. leviuscula
variety B, characterized by aboral spines “stout with a thorny apical knob as found on typical specimens from Monterey Bay” (
Djakonov, 1950: figs. 83, 84
) is not
H. leviuscula
but another species possibly still undescribed.
Fisher (1911)
reported that
leviuscula
in “typical form” (his variety B) occurred from the Aleutian Islands, Alaska, to Monterey Bay, California, and that southern specimens that were not “typical” extended to Santa Barbara Channel and San Diego, California. In contrast,
Verrill (1914)
considered
H. leviuscula
to be a “southern” form, noting that most of Fisher's specimens were from sites south of Sitka, Alaska. We have confirmed Fisher's identification of some
H. leviuscula
from near Sitka and Fort Wrangel (Alaska), Port Renfrew (Vancouver Island, British
Columbia
), Port Townsend (North Puget Sound), and Hecata (= Heceta) Bank off Oregon.
Djakonov (1950, figs. 79, 80)
described and illustrated his variety A from a specimen from Nanaimo, British
Columbia
and said that it had spines like those of the
holotype
.
Uchida (1928)
described a single specimen of
leviuscula
from
Japan
, but
Hayashi (1940)
compared material from
Japan
with specimens thought to be of
leviuscula
from Kodiak, Alaska, and concluded that
leviuscula
was not present in collections from Japanese waters.
Djakonov (1950)
reported
leviuscula
from the Sea of
Japan
, but later (
Djakonov 1961: 23
), having decided that at least two species were known under the name, stated it difficult to define the true range, which might include Sea of
Japan
and near Paramushir Island of the Kurile Islands.
Hayashi (1973: 11)
did not list
leviuscula
among seastars from
Japan
. We did not find
leviuscula
in a small sample of representative species from
Japan
kindly made available to us by Mr. Masaki
Saba
and Mr. Yasuo Kano through the courtesy of Dr. Chitaro Oguro and Dr. Mieko Komatsu.
H. leviuscula
is distinct from congeners described from Japanese waters (
Hayashi 1940
,
1973
) or the North Atlantic (
Heding 1935
;
Rasmussen1965
;
Madsen 1987
,
A. M. Clark & Downey 1992
), and we have not seen any specimens of
H. leviuscula
as restricted herein from north or west of Kenai Peninsula, Alaska or south of Puget Sound, Washington. In the northern part of its range, in southeastern Alaska, it appears to be less common than its similar congeners (D. Eernisse and M. Strathmann, in prep.) and it is likely endemic to northeastern Pacific cool temperate coastal areas (northern Oregonian province).