fissidentalium (compressidentalium) pseudohungerfordi n. sp., a … · 2017. 11. 24. ·...

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Schr. Malakozool. 29 19-32, pls. 9-19 Cismar, Ostholstein, 30.4.2016 ISSN 0936-2959

Fissidentalium (Compressidentalium) pseudohungerfordi n. sp., a well known undescribed scaphopod in the group of

Fissidentalium (Compressidentalium) hungerfordi (PILSBRY & SHARP 1897) (Mollusca: Scaphopoda).

By BERND SAHLMANN1, JORDY VAN DER BEEK2 & VOLLRATH WIESE1 1Cismar and 2Rotterdam

Abstract: A huge number of shells belonging to the group which traditionally was called Fissidentalium (Compressidentalium) hungerfordi (PILSBRY & SHARP 1897) was analysed. By comparison with the original diagnoses and pictures of the types three species were distinguished of which one was discovered to be unknown. Most of the specimens studied belong to this new species Fissidentalium (Compressidentalium) pseudohungerfordi n.sp. which can easily be distinguished by the lower number of ribs. Only shells from the South China Seas and some from Japanese waters could be assigned to F. hungerfordi.

Introduction: The variability of the bright yellow or orange coloured scaphopods from Eastern and

Southeastern Asia has confused us for many years. When starting the intenser research on “Fissidentalium hungerfordi”-like scaphopods, the first aim (SAHLMANN 2015) was to clarify the status and distribution of F. sibogae (BOISSEVAIN 1906). This analysis gives reason to have a closer look to the remaining specimens. Differences in rib number, rib shape and overall shape are obvious on a second look. The shells from South China Seas and some shells from Japanese waters could be attributed to fit with the original diagnosis of F. hungerfordi as given by SOWERBY (1889) and PILSBRY & SHARP (1897), whereas especially all F. hungerfordi-like shells from Philippine waters seem to be different (SAHLMANN & WIESE 2015).

Having already observed the first differences in an early stage of the research more than a decade ago, in the meantime a large number of these comparably uncommon species were assembled to verify the stability of the grouping. Now more than 100 specimens of the species around Fissidentalium hungerfordi could be studied, more than 70 of them different from the known species F. hungerfordi and F. sibogae. The genus Fissidentalium still needs systematic clarification. Whether all species regardless their dimensions and shape of aperture should be lumped together, or the species with a more or even less compressed shell should be separated as belonging to Compressidentalium HABE 1963, used as a subgenus or even in generic rank, as it was done by SCARABINO (1995), is still open to discussion. At the moment, we prefer to use Compressidentalium as a subgenus of Fissidentalium.

Material: Specimens of shells of the group of Fissidentalium hungerfordi from the scaphopod

collection of the “Haus der Natur – Cismar” (HNC) and the private collection of JORDY VAN DER BEEK (JvdB), were analysed. The intense discussions with our friend ARIE FRANS DE JONG during the Scaphopod Workshops in Cismar were of great help to clarify the status of the specimens.

Fissidentalium (Compressidentalium) pseudohungerfordi n. sp.

Diagnosis: Shell straight, slightly curved in the posterior part if not truncated, shell obviously increasing towards aperture; about 27 (16-36) ribs near the mouth, about 11 to 26 ribs near the apex (near the anterior end of the slit). Intercalation (addition of secondry ribs) starts near the apex with finer additional riblets that become more or less identical to the primary ribs. Ribs may vary from flat to elevated, ribs of variable size at dorsal side, interstices as wide as the ribs with a very finely cancellated sculpture. Apex with a narrow slit of considerable length, slit sometimes notch-like or absent, due to the degree of truncation. Colour cream or light to bright orange with some lighter or darker bands, ventral

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side most times less coloured, colour tends to fade with time, dead shells taken from the sediment often in shades of uniform cream or brown. Ventral and dorsal side of the aperture convex in shape. Depending on the prominence of the ribs the aperture is mostly obviously crenulated. In section, shell towards the mouth compressed dorsoventrally to an oval of various degree.

The total length is up to more than 90 mm, the mouth up to 13.7 mm x 11.1 mm. The shells studied weigh from 0.8 g to 5.2 g, the average weight per length is 0.33 g/cm.

Etymology: The hitherto overlooked new species was named referring to the closely allied and confused species F. (C.) hungerfordi with its name giving person RICHARD HUNGERFORD and pointing out the evidence of a cryptic species

Type locality: Off Bohol Island, Philippines Range: Philippines, Indonesia, New Caledonia, Japan (Tosa Bay area). Habitat: Depths from 30 m to 350 m, probably also in greater depths.

Schr. Malakozool., 29, 2016 Plate 9

Explanations of Plate 9:

Fissidentalium pseudohungerfordi n. sp., Philippines, Palawan, large specimen, 89.2 mm, HNC 86245

Type material and figures: Holotype: HNC 84465a, Philippines, Bohol Island, collected by local fishermen,

Length (L) = 59.6 mm, aperture width (Aw) = 8.5 mm, aperture height (Ah) = 6,9 mm, 1.18 g, Pl. 10 Paratype 1: HNC 84465b, Philippines, Bohol Island, collected by local fishermen,

L = 77.3 mm, Aw = 11.6 mm, Ah = 9.6 mm, 3.8 g, Pl. 11 Paratype 2: HNC 75151, Philippines, Siquijor, 150 m, L = 59.0 mm, Aw = 8.9 mm, Ah = 7.6 mm, 1.10 g, Pl. 12 Paratype 3: HNC 84474, Philippines, Balicasag, 80-120 m, L = 62.3 mm, Aw = 8.3 mm, Ah = 7.3 mm, 0.90 g, Pl. 13 Paratype 4: HNC 75136, Philippines, Balicasag, L = 57.6 mm, Aw = 8.2 mm, Ah = 6.8 mm, 1.28 g., Pl. 14 Paratype 5: NHMUK (ex HNC 84472), Philippines, Siquijor Paratype 6: Naturalis RMNH.5004011 (ex HNC 84262), Philippines, Siquijor HNC 86245: Philippines, Palawan, L = 89.2 mm, Aw = 11.4 mm, 9.6 mm, 4.08 g, Pl. 9 HNC 84479a: Japan, Wakayama, L = 76.5 mm, Aw = 11.0 mm, 9.3 mm, 3.01 g, Pl. 15 HNC 75322: Philippines, Balicasag, L = 62.3 mm, Aw = 12.9 mm, Ah = 9.7 mm, 2.42 g, Pl. 16 Multiple figures of the type material of the related Fissidentalium hungerfordi (Lectotype BMNH 1889.2.1.1-2a, lectotype selected by SCARABINO 1995, p. 258 and Paralectotype) are given in this issue of Schr. Malakozool. a few pages before (SAHLMANN & WIESE 2016, figs. 1, 2, 3, 4, 5, 10), for Fissidentalium sibogae see also SAHLMANN (2015).

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Comparisons and remarks: P. pseudohungerfordi n. sp. differs from F. (C.) hungerfordi in its much lower number of ribs (an

average of 27 ribs versus about 82), more prominent ribs and in most cases in a more slender shape. F. (C.) sibogae differs in its explicitely triangular aperture and its larger weight of the shell. More details of the measurements are given in the table below.

Fissidentalium (C.) hungerfordi

(n = 15)

Fissidentalium (C.) pseudohungerfordi n. sp.

(n = 73)

Fissidentalium (C.) sibogae (n = 9)

Length - mm 63.0 (± 7.2) (53.6–77.4) 64.3 (± 10.8) (43.1–89.2) 76.2 (± 6.9) (63.9–87.1) Aperture width Aw - mm 10.8 (± 1.2) (8.7–12.5) 10.3 (± 1.5) (7.5–13.7) 14.1 (± 1.6) (11.1–16.0) Aperture height Ah - mm 9.08 (± 1.0) (7.6–10.6) 8,47 (± 1.14) (6.5–13.7) 10.4 (± 0.9) (8.6–11.9) Aw/Ah 1.18 (± 0,03) (1.14–1.24) 1.22 (± 0.05) (1.14–1.37) 1.4 (± 0.10) (1.3–1.5) Aw–Ah 1.65 (± 0.34) (1.1–2.3) 1.86 (± 0.48) (0.9 – 3.4) 3.78 (± 1.11) (2.5–5.6) Ribs at aperture - number 81.5 (± 16.00) (54–104) 27.3 (± 5.00) (16–36) 48.6 (± 8.24) (40–62) Ribs at adapical end of slit 19.5 (± 5.48) (12–26) 14.8 (± 2,12) (11–26) 19.3 (± 2.78) (15–23) Weight - g 2.90 (± 1.18) (1.46–5.72) 2.18 (± 1,01) (0.78–5.16) 5.04 (± 1.56) (2.3–6.9) Weight per mm - g/mm 0.45 (± 0.13) (0.27–0.69) 0.33 (± 0.11) (0.14–0.61) 0.65 (± 0.16) (0.36–0.88)

Table 1: Mean values (standard deviation) (extreme values) of the measurements of Fissidentalium hungerfordi and its

related species. Some additional specimens without locality data or with very questionable information concerning their origin were inspected, but were excluded from the countings and calculations. In a few specimens of F. pseudohungerfordi some measurements wouldn't make sense (e.g. weight in specimens with attached other animals, such as sponges or molluscs), these were not included in the avaraged data.

The old species Fissidentalium (Compressidentalium) zanzibarense PLATE 1908 or Fissidentalium

(Compressidentalium) sumatrense BOISSEVAIN 1906 are too poorly known to clarify their relations to F. (C.) pseudohungerfordi n. sp.

Conclusions: Careful inspection of the shell morphology shows that F. pseudohungerfordi n. spec. can be easily

distinguished from F. sibogae and F. hungerfordi by rib count and shape of the shell. It is not always easy to find out which of both sibling species is mentioned in the literature. Most publications (e.g. OKUTANI 2000, MA 2004, POPPE 2011, ROBIN 2011, SAHLMANN 2015) clearly figure shells of F. pseudohungerfordi instead of F. hungerfordi. SCARABINO (1995) and SAHLMANN & WIESE (2016) are showing the “true” F. hungerfordi.

At present knowledge, all Philippine specimens of the group of F. hungerfordi, which are not F. sibogae, are belonging to the new species F. pseudohungerfordi, whereas all shells from the Chinese waters seems to be F. hungerfordi. Shells from Japanese waters may belong to all three species. In the Tosa Bay area all three species are reported together, which is a good argument against speculations about biological or ecological reasons of shell related differences in these particular species.

For more than a century one of the most beautiful and presumably well known scaphopod species, present in most shell collections, was intermingled with another, but easily discriminable species. This shows how easily specialists and collectors minds could be fooled over a long time.

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SAHLMANN, VAN DER BEEK & WIESE: Fissidentalium hungerfordi and F. pseudohungerfordi n. sp.


Fissidentalium pseudohungerfordi n. sp., Holotype Philippines, Siquijor, 59,6 mm, HNC 84465a

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Fissidentalium pseudohungerfordi n. sp., Paratype 1 Philippines, Siquijor, 77,3 mm, HNC 84465b

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Fig. 3: Fissidentalium pseudohungerfordi n. sp., Paratype 2 Philippines, Siquijor, 59,0 mm, HNC 75151

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Fissidentalium pseudohungerfordi n. sp., Paratype 3 Philippines, Balicasag, 80-120 m, 62,3 mm, HNC 84474

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Fissidentalium pseudohungerfordi n. sp., Paratype 4 Philippines, Siquijor, 57.6 mm, HNC 75136

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Fissidentalium pseudohungerfordi n. sp., Japan, Wakayama, 76.5 mm, HNC 84479a

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Fissidentalium pseudohungerfordi n. sp., broad specimen Philippines, Balicasag, 62.3 mm, HNC 75322

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Fissidentalium pseudohungerfordi n. sp. with unusual secondary colonization: specimen with a glass sponge at its apical end, Philippines, Siquijor, 200 m (HNC 84263)

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Fissidentalium pseudohungerfordi n. sp. with unusual secondary colonization: Old empty shell inhabited by a specialized hermit crab (dried specimen),

on the shell male and female specimens of Capulus spec. are settled and relics of dried sea anemones are present. Philippines, Siquijor Island, 200 m (HNC 84464).

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Fissidentalium (C.) pseudohungerfordi n. sp., empty shell and fragment collected and mounted by the carrier shell Xenophora pallidula (REEVE 1842) (Family Xenophoridae),

off Balicasag Island, Philippines, 150 m (HNC 86163).

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References: ANONYMOUS (2006): RICHARD HUNGERFORD, PATRICK MANSON and a small contribution to the understanding of tropical disease.

-- Mollusc World, 10: 22, Bedfordshire. BOISSEVAIN, M. (1906): The Scaphopoda of the Siboga Expedition treated together with the known Indo-Pacific Scaphopoda. --

Siboga Expeditie, 54: 1-76, pls. 1-6, Brill, Leiden. HABE, T. (1957): Report on the Mollusca Chiefly Collected by the S. S. Soyo-Maru of the Imperial Fisheries Experimental

Station on the Continental Shelf Bordering Japan During the Years 1922-1930. Part 2. Scaphopoda. -- Publications of the Seto Marine Biological Laboratory 6 (2): 127-136, pls. 37-38, Kyoto.

HABE, T. (1963): A classification of the scaphopod mollusks found in Japan and its adjacent areas. -- Bulletin of the National

Science Museum Tokyo, New Series, 6 (3): 252-281, pls. 37-38, Tokyo. HABE, T. (1964): Fauna Japonica Scaphopoda (Mollusca). -- 59 pp., 5 pls., Biogeographical Society of Japan, Tokyo. MA, X. (2004): Scaphopoda. -- in: QI Z. (ed), Seashells of China, 200-205, pls. 109-110. – Beijing (China Ocean Press). MACDONALD, M. (2014): Expansion of Hong Kong International Airport into a Three-Runway System Environmental Impact

Assessment Report. Appendix 13.5 Marine Ecology Field Survey Result Excluding CWD with annexes. -- 226 pp. OKUTANI, T. (2000): Marine Mollusks in Japan. -- 1173 pp., 542 pls., Tokai University Press, Tokyo. PLATE, T. (1908): Die Solenoconchen der Valdivia-Expedition. -- Wissenschaftliche Ergebnisse der Deutschen Tiefsee-

Expedition 1898-1899 Dampfer "Valdivia", Vol. 9 (3): 337-362, pl.30, Fischer, Jena. PILSBRY, H. A. & SHARP, B. (1897-1898): Scaphopoda. -- in: TRYON, G. W. & PILSBRY, H. A. (eds.), Manual of Conchology, Ser.

1, Vol. 17: 280 pp., 39 pls., Philadelphia. POPPE, G. T. (2011): Philippine Marine Mollusks. -- Vol. IV (Bivalvia Part 2, Scaphopoda, Polyplacophora, Cephalopoda &

Addenda), 676 pp., pls. 1015-1315, ConchBooks, Hackenheim. [with 12 coauthors]. ROBIN, A (2011): Encyclopedia of Marine Bivalves Scaphopoda, Polyplacophora and Cephalopoda. -- 302 pp, AFC-Xenophora,

Paris & ConchBooks, Hackenheim. SAHLMANN, B. (2011): Bibliography of the Scaphopod Molluscs of the Philippine Archipelago and Surrounding Waters. --

Schriften zur Malakozoologie, 26: 47-52, Cismar. SAHLMANN, B. (2015): Fissidentalium (Compressidentalium) sibogae (BOISSEVAIN 1906) - An Exceptional Shaped Scaphopod

Shell from the Philippines (Mollusca Scaphopoda). -- Schriften zur Malakozoologie, 28: 37-48, Cismar. SAHLMANN, B. & WIESE, V. (2016): The Real Fissidentalium (Compressidentalium) hungerfordi (PILSBRY & SHARP 1897)

(Mollusca Scaphopoda). -- Schriften zur Malakozoologie, 29: 7-18, Cismar. SCARABINO, V. (1995): Scaphopoda of the tropical pacific and Indian Oceans, with description of 3 new genera and 42 new

species. -- in: BOUCHET P. (ed.), Resultats des Campagnes MUSORSTOM, Vol. 14. -- Mémoires du Museum d'Histoire Naturelle, 167: 189-379, Paris.

SCARABINO, V. (2008): New species and new records of scaphopods from New Caledonia. -- in: HÉROS V., COWIE R.H.,

BOUCHET P. (eds), Tropical Deep-Sea Benthos 25. -- Mémoires du Museum d'Histoire Naturelle, 196: 215-268, Paris. SOWERBY, G. B. (1889): Description of fourteen new species of shells from China, Japan, and the Andaman islands, chiefly

collected by Deputy Surgeon-Gen. R. HUNGERFORD. -- Proceedings of the Scientific Meetings of the Zoological Society of London for the year 1888 (4): 565-570, pl. 28, London.

STEINER, G. & KABAT, A. R. (2001): Catalogue of supraspecific taxa of Scaphopoda (Mollusca). -- Zoosystema, 23 (3):

433-460, Paris. STEINER, G. & KABAT, A. R. (2004): Catalogue of species-group names of recent and fossil Scaphopoda (Mollusca). --

Zoosystema, 26 (4): 549-726, Paris.

Addresses of the authors: Dr. BERND SAHLMANN, Haus der Natur - Cismar, Bäderstr. 26, 23743 Cismar, Germany, [email protected] JORDY VAN DER BEEK, Natural History Museum Rotterdam, Westzeedijk 345 (Museumpark), 3015 AA Rotterdam, The Netherlands, [email protected] Dr. VOLLRATH WIESE, Haus der Natur - Cismar, Baederstr.26, 23743 Cismar, Germany [email protected]

fissidentalium (compressidentalium) pseudohungerfordi n. sp., a … · 2017. 11. 24. ·...

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