Research Article |
Corresponding author: Rob W.M. Van Soest ( rob.vansoest@naturalis.nl ) Academic editor: Roberto Pronzato
© 2015 Rob W.M. Van Soest, Bert W. Hoeksema, James D. Reimer, Nicole J. De Voogd.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Van Soest RWM, Hoeksema BW, Reimer JD, De Voogd NJ (2015) New records of the rare calcareous sponge Paragrantia waguensis Hôzawa, 1940. ZooKeys 546: 1-20. https://doi.org/10.3897/zookeys.546.6122
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Paragrantia waguensis Hôzawa is reported from coastal reefs of the island of Okinawa. This rare species was previously known only from Central Japan, Mie Prefecture. It has peculiar apopylar tetractine spicules, so far unique among Calcarea. We present in situ images of the species and a full description including SEM images of skeletal structure and spicule complement. The status of Paragrantia as a separate genus of the family Grantiidae distinct from Grantia Fleming is confirmed on the basis of a morphological and molecular comparison with the European type species of Grantia, G. compressa (Fabricius).
Porifera , Calcarea , Leucosolenida , Grantiidae , Japan, apopylar spicules
We report here the recent collection (2006, 2014) of a rare and curious calcareous sponge species from Okinawa, Paragrantia waguensis
Paragrantia
The major revision of the Calcarea presented in the framework of the Systema Porifera project (
Despite Hôzawa’s excellent description and generally good illustrations of Paragrantia waguensis, we feel induced by its subsequent lack of proper evaluation, to once again draw attention to it. Here, we fully describe our specimens, providing in situ photos, compare it with Hôzawa’s description (unfortunately the type material itself, kept in the Tôhoku
Specimens were collected using SCUBA by J. Tanaka (University of the Ryukyus) in 2006, and by BWH, as a guest of JDR, in 2014, subsequently identified by NJDV and RWMVS, and registered in the
Specimens were sectioned by hand: cross sections perpendicular to the surface and tangential sections of the outer surface (cortical region), the inner surface (atrial region), and the oscular fringe. The sections were air dried, mounted on stubs, and sputter coated for examination under SEM. Spicules were dissociated using household bleach, washed five times in distilled water, and subsequently plated on glass slides for light-microscopic measurements and on SEM stubs for examination and micrographing under SEM.
Measurements of the spicules are given as smallest-average-largest of 25 spicules of each distinct type.
To verify the conclusions from the morphological comparison of Paragrantia waguensis with Grantia compressa, a 28S rDNA sequence (430 bp) of Paragrantia waguenis (sample
With the obtained sequence we performed a BLAST analysis provided by the NCBI website (http://blast.ncbi.nlm.nih.gov/Blast.cgi), and downloaded a representative set of partial 28S sequences of calcaronean species showing up in the BLAST result. The set of sequences included a sequence of Grantia compressa provided by
Leucosolenida species of which partial 28S sequences were downloaded from the NCBI website (http://www.ncbi.nlm.nih.gov/) and were used for an evaluation of the phylogenetic relationships of Paragrantia waguensis and Grantia compressa. From left to right columns list genus, species and family names, accession numbers of the sequences, and literature sources. The results of the phylogenetic analysis are represented in Fig.
Genus | Species | Family | Accession number | Source |
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Paragrantia | waguensis | Grantiidae | KT277668.1 | present study |
Grantia | compressa | Grantiidae | AY563538.1 |
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Ute | ampullacea | Grantiidae | JQ272226.1 |
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Leucandra | nicolae | Grantiidae | JQ272268.1 |
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Leucandra | aspera | Grantiidae | AY563535.1 |
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Leucandra | sp. | Grantiidae | JQ272265.1 |
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Aphroceras | sp. | Grantiidae | AM181001.1 |
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Teichonopsis | cylindrica | Grantiidae | JQ272264.1 |
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Synute | pulchella | Grantiidae | JQ272274.1 |
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Sycon | capricorn | Sycettidae | AM181000.1 |
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Scypha (=Sycon) | raphanus | Sycettidae | AY563537.1 |
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Anamixilla | torresi | Jenkinidae | AY563536.1 |
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Leucascandra | caveolata | Jenkinidae | JQ272259.1 |
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Paraleucilla | magna | Amphoriscidae | JQ272267.1 |
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Paraleucilla | sp. | Amphoriscidae | AY563540.1 |
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Grantiopsis | heroni | Lelapiidae | AY563539.1 |
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The systematic classification generally follows the Systema Porifera (
Paragrantia waguensis Hôzawa, 1940: 40, pl. V figs 8–11, text-fig. 4;
Grantia waguensis;
Naturalis Biodiversity Center, reg. nr.
Syntype, 8 specimens (not seen) Tôhoku UniversityMuseum, reg.nr. TUMC 110908, Japan, Central Kuroshio ecoregion, Mie Prefecture, Wagu, approximately 34.25°N, 136.8°E, coll. S. Hôzawa, July 1933.
Cup-shaped or tubular specimens (Fig.
Habitus of Paragrantia waguensis. ain situ photo of oval cup-shaped individual at Manza, Okinawa (photo B.W. Hoeksema of
Aquiferous system. No histological slides were made, but the structure of the skeleton suggests it is syconoid (as was also the case in Hôzawa’s material). There is no evidence of branching choanocyte chambers. Subcortical lacunae are present, regularly distributed and apparently serving as inhalant reservoirs.
Skeleton of the walls. (Figs
SEM images of atrial region of Paragrantia waguensis and its atrial spicules. a overview of atrial surface with atrial chambers b detail of atrial apopylar chambers showing the position of the apopylar spicules c apopylar spicules c1 details of apical actines of c d atrial triactine e atrial tetractines.
Skeleton of the fringe. (Fig.
Spicules. Cortical triactines, tubar triactines, subatrial triactines, atrial triactines, atrial tetractines, apopylar tetractines, diactines from the fringe, triactines from the fringe, tetractines from the fringe.
Cortical triactines (Fig.
Tubar triactines (Fig.
Subatrial triactines (Fig.
Atrial triactines (Fig.
Atrial tetractines (Fig.
Atrial exhalant chamber tetractines (apopylar tetractines) (Figs
Diactines (Fig.
Tetractines (Fig.
Triactines (Fig.
No data were provided by Hôzawa, but the Okinawa specimens were from a steep reef slope at 20–55 m depth, growing among coralline and turf algae, and encrusting sponges.
Warm-temperate (Mie Prefecture) and subtropical (Okinawa) regions of Japan.
The habit of Hozawa’s specimens is described from eight preserved individuals. A photo is given of two specimens (
The general structure of the skeleton and the overall diversity and sizes of the spicules likewise match closely (as can be observed from Table
Paragrantia waguensis, spicule size data (micrometers). The data of the type specimens from Wagu (taken from Hôzawa 1941) are compared to those of specimens from Okinawa (our own measurements of
a. Spicules of the cortex and the chamber layer | ||||||||
cortical triactines | tubar triactines | subatrial triactines | ||||||
unpaired | paired | unpaired | paired | unpaired | paired | |||
Type specimens: Wagu | 80-420 x 8-20 | 50-220×4-16 | 140-225×10-16 | 90-160×10-16 | 180-350×8-10 | 65-110×8-10 | ||
Okinawa | 48-315×6-24 | 40-242×9-23 | 93-270×8-21 | 92-241×9-21 | 207-291×6-10 | 61-111×6-10 | ||
b. Spicules of the atrial region | ||||||||
atrial triactines | atrial tetractines | apopylar triactines | ||||||
unpaired | paired | unpaired | paired | apical | unpaired | paired | apical | |
Type specimens: Wagu | 100-390×8-10 | 70-200×8-10 | 100-390×10 | 115-170×10 | 40-90×12 | 20-25×4 | 56-70×4 | 20×12-18 |
Okinawa | 150-354×8-11 | 114-261×7-12 | 42-226×7-10 | 105-171×7-10 | 30-63×6-12 | 14-39×3-5 | 27-78×3-5 | 13-24×5-10 |
c. Spicules of the fringe | ||||||||
Fringe diactines | Fringe triactines | Fringe tetractines | ||||||
unpaired | paired | unpaired | paired | apical | ||||
Type specimens: Wagu | 300-880×14-28 | 340×10 | 150×12 | 150-420×8 | 150-200×10 | 20-40×10 | ||
Okinawa | 360-990×12-29 | 156-279×6-10 | 63-105×7-10 | 165-528×9-15 | 81-273×8-12 | 16-76×5-10 |
Nevertheless, there are a few clear differences:
The unpaired actines of the atrial tetractines in Hôzawa’s specimens were given as large as up to 390 µm, whereas in our specimens they were only up to 226 µm.
The apical actines of the apopylar tetractines in Hôzawa’s specimens were given as having a width of 12–18 µm, whereas ours were only 5–10 µm.
The tetractines of the fringe in Hôzawa’s specimens were smaller and thinner: e.g. unpaired actines were 150–420 × 8 µm, whereas in our specimens these measured 165–528 × 9–15 µm.
We believe that these differences are too small to consider them as evidence for specific distinction.
By its possession of a cortical skeleton, an articulated choanosomal skeleton, and lack of pseudosagittal spicules, the present species fits the family Grantiidae. In order to decide whether Hôzawa was right in establishing a new genus for his species waguensis, it is necessary to know the properties of the other genera of the family. The syconoid aquiferous system and the absence of long longitudinally arranged diactines (except in the fringe) limits the generic relationships of waguensis to Grantia Fleming (1828), Sycandra
The sample we studied consisted of a cluster (Fig.
Habitus and skeleton of Grantia compressa from Roscoff, W coast of France (
Grantia compressa and Paragrantia waguensis differ in the following features:
In life, G. c. is a flattened, purse-shaped sponge, P. w. is a cup or wide-mouthed tube.
G. c. lacks a distinct fringe, P. w. has a clear, differently colored, fringe containing special spicules with sizes not occurring in the rest of the body.
Cortical skeleton of G. c. has club-shaped diactines in clusters, lacking in P. w.
Cortical skeleton of G. c. is thin and contains small triactines, P. w. has a thick cortical skeleton including much larger triactines.
Tubar triactines, subatrial triactines, atrial tri- and tetractines of G. c. are all smaller and thinner than those of P. w.
A special apopylar skeleton and spicules are lacking from G. c. and is the dominant feature in P. w.
To date the World Porifera Database (
Other, not further specified groups of species may be distinguished e.g. on the possession of long protruding diactines (‘hairy’ Grantia’s), or those lacking tetractines, etc.
All these species do not have the apopylar specialization of P. waguensis. However, a few species assigned to the genus Grantia do appear to have at least a special category of atrial spicules, next to the usual atrial tri- and tetractines, viz. smaller tetractines in the apopylar region in G. atlantica
A further differentiation between the two type species of the genera Paragrantia and Grantia was obtained from sequences. The molecular classification of the Calcarea and its subclasses, orders and families is still in its early stages (see e.g.
Phylogenetic tree (Maximum Likelihood, 50% majority consensus) of selected 28S partial sequences of calcareous sponge species belonging to the order Leucosolenida, including Paragrantia waguensis and Grantia compressa (asterisks). Sequences were downloaded from the NCBI website (http://www.ncbi.nlm.nih.gov/). The accession numbers and sources for the sequences are listed in Table
Until a revision of Grantia along the lines sketched above has been made – preferably guided by independent molecular markers of the studied taxa – we propose to maintain Paragrantia as a separate genus, so far monotypic with P. waguensis as the only species. Its status is comparable to other such genera (Sycandra and Teichonopsis), recognizable by unique features, as in this case the unique butterfly-shaped apopylar tetractines, for which we introduce the term ‘aliactines’ (from ala (L.) = wing).
We propose here the following definition (modified from
Genus Paragrantia Hôzawa, 1940
Type species. Paragrantia waguensis Hôzawa, 1940 (by monotypy)
Syconoid Grantiidae with cortical skeleton of triactines, articulate tubar skeleton composed of aligned triactines, and an oscular fringe with giant diactines and sagittal tri-and tetractines. Atrial skeleton composed of subatrial triactines, and atrial triactines and/or tetractines. Choanocyte chambers connect with the atrial lumen through apopylar chambers lined with modified specialized tetractine spicules (aliactines).
Dr. J. Tanaka (Department of Chemistry and Marine Science, University of the Ryukyus, Okinawa) is thanked for donating the Onna specimens. Mr. Jun Nemoto, technical staff of the Tôhoku UniversityMuseum, provided information on the type material. Ms Aline Nieman (Naturalis DNA Laboratory) provided the sequence of P. waguensis. Special thanks are due to Bastian Reijnen MSc. for advice and help with the phylogenetic analysis.