Biemna humilis Thiele, 1903: 944 Desmacella tubulata sensu Dendy 1916: 116 Sigmatoxella humilis Pulitzer-Finali 1982a: 107 Mycale aff. c ockburniana Van Soest 1990: 305 Erhardt & Baensch 1998: 54 Desmacella humilis Pulitzer-Finali 1993: 293 Kerasemna humilis Richmond et al. 2011: 122 Mycale (Mycale) vansoesti Calcinai et al ., 2006: 197 Mycale (Mycale) corallina Calcinai et al. 2017 Mycale calcinaiae Van Soest & Hooper, 2020: 63 Mycale humilis Mycale species of the tropical Indo-West Pacific (Porifera, Demospongiae, Poecilosclerida) Van, Rob W. M. Aryasari, Ratih De, Nicole J. Zootaxa 2021 2021-01-19 4912 1 1 212 86X4L (Thiele, 1903) Van & Aryasari & De 2021 Thiele 1903 [151,680,834,861] Demospongiae Mycalidae Mycale Animalia Poecilosclerida 97 98 Porifera species humilis comb. nov. Kerasemna   Figs 61a–d, 62a–f, 63a–g, 64      Biemna humilis Thiele, 1903: 944, fig. 10.   ?   Desmacella tubulata sensu Dendy 1916: 116(not: Dendy 1905).    Sigmatoxella humilis;  Pulitzer-Finali 1982a: 107.    Mycaleaff. c ockburniana;  Van Soest 1990: 305;  Erhardt & Baensch 1998: 54(not: Hentschel 1911)   ? Desmacella humilis;  Pulitzer-Finali 1993: 293.   ? Kerasemna humilis;  Richmond et al.2011: 122, fig. p. 123.     Mycale (Mycale) vansoesti Calcinai et al., 2006: 197, figs 3A–C, 4A–F, 5A–J, 6A–F (not: Hajdu 1995).   Mycale (Mycale) corallina Calcinai et al.2017: Supplementary file 2.   Mycale calcinaiaeVan Soest & Hooper, 2020: 63.   Mycale humilis; Van Soest & Hooper, 2020: 63.   Material examined. ZMB3203, two slides of holotypeof  Biemna humilis(slides labeled as  Desmacella humilis), Indonesia, Ternate, coll. W. K̹kenthal, 1893–1894; MSNG52803, paratypeof  Mycale (Mycale) vansoesti Calcinai et al., 2006, Indonesia, N Sulawesi, Siladen Station, depth 17 m, 28 May 2002.   ZMA Por.02905, Indonesia, Lesser Sunda Islands( Nusa Tenggara), Postillion Islands, anchorage off Pulau Sarassa, 7.1833°S 118.2°E, coral bottom, depth  36 m, dredge, coll. Siboga Expedition stat. 043, field nr. SE829I, 4 April 1899;  ZMA Por.08028, Indonesia, Nusa Tenggara East, Komodo, NEcape, 8.4833°S 119.5683°E, depth  1–4 m, snorkeling, coll.  R. W.M. van Soest, Indonesian-Dutch Snellius  II Expeditionstat. 096, field nr. 096/  II/02,  19 September 1984(live color yellow);  ZMA Por.08564, Indonesia, Sulawesi, SE Sulawesi, Taka Karlarang, reef, depth  6–8 m, SCUBA, coll.  R. W.M. van Soest, Indonesian-Dutch Snellius  II Expeditionstat. 147, field nr. 147/  III/11,  27 September 1984(yellow);  ZMA Por.08953, Sulawesi, SE Sulawesi, SW Salayar, reef N of Pulau Bahuluang, 6.45°S 120.43°E, depth  10–15 m, SCUBA, coll.  R. W.M. van Soest, Indonesian-Dutch Snellius  II Expeditionstat. 169, field nr. 169/  IV/24,  30 September 1984(light yellow);  ZMA Por.09753, Papua New Guinea, no further data, dried, coll. M.C. Díaz, field nr. 90152 (orange-red);  ZMA Por.12970, Indonesia, N Sulawesi, Bunaken Island, 1.6132°N 124.7797°E, reef drop-off, dried, coll. H. Erhardt,  22 September 1996(white-purple, photo in Erhardt & Baensch 1998);  ZMA Por.13327, Indonesia, Sulawesi, SW Sulawesi, Spermonde Archipelago, Samalona, reef, depth  6 m, SCUBA, coll. N.J. de Voogd, field nr.  SA/NV/060597/03,  6 May 1997(white-purple);  ZMA Por.14523, Indonesia, N Sulawesi, Bunaken, ESE Siladen Island, 1.6317°S 124.8053°E, depth  18 m, coll. B.W. Hoeksema, SYMBIOSPONGE Expedition, field nr. 98/NS/MAY07/BH/077, 7 May 1998(white);  ZMA Por.15829, Madagascar, Nosy B, Crater Bay, depth  4–10 m, muddy reef bottom,  SCUBA, coll. J.H. Stock,  21 December 1963(orange);  ZMA Por.16832, Indonesia, Maluku, Ambon, Tanjung Setan, depth  20 m,  SCUBA, coll. S. Weinberg,  20 August 1995(orange);  RMNH Por.1608, Palau, Koror, Ngerikuul Pass, E of Ngetekiou Island, pass between Ngeteklouand Ngermeuangel Island, 7.3167°N 134.5167°E, depth  8 m,  SCUBA, coll. N.J, de Voogd, field nr.  KOR02/120505/003,  12 May 2005(green);  RMNH Por.1609, Palau, Koror, Ngerikuul Pass, E of Ngetekiou Island, pass between Ngeteklouand Ngermeuangel Island, 7.3167°N 134.5167°E,  SCUBA, coll. N.J, de Voogd, field nr.  KOR02/210505/095,  21 May 2005;  RMNH Por.1610, Palau, Koror, Ngerikuul Pass, E of Ngetekiou Island, pass between Ngeteklouand Ngermeuangel Island, 7.3167°N 134.5167°E,  SCUBA, coll. N.J, de Voogd, field nr.  KOR02/210505/096,  21 May 2005;  RMNH Por.2150, Bali, Nside of Nusa Penida, off Desa Buyuk, 8.6736°S 115.5436°E, depth  0–30 m,  SCUBA, coll. N.J. de Voogd, Bali-Lombok Strait Expedition2001, field nr. BAL.34/210401/259,  21 April 2001(white);  RMNH Por.2190, Bali, Padang Bai, Eside Tanjung Sari, 8.5294°S 115.5131°E, shallow slope, depth  0–30 m,  SCUBA, coll. N.J. de Voogd, Bali-Lombok Strait Expedition2001, field nr. BAL.19/080401/097,  8 April 2001(white);  RMNH Por.2608, Singapore, Pulau Tekukor( Monkey Island), NW side, 1.2308°N 103.8365°E, depth  12 m,  SCUBA, coll. N.J. de Voogd, field nr. SIN.23/040406/170,  4 April 2006(yellow);  RMNH Por.2617, Indonesia, Sulawesi, SW Sulawesi, Tanjung Bira, Pulau Liukan, 5.65°S 120.43°E, depth  25 m,  SCUBA, coll. N.J. de Voogd, field nr. BIR05/230501/242,  23 May 2001;  RMNH Por.2618, Indonesia, North Sulawesi, SW Siladen Island, 1.6167°N 124.7833°E, depth  15 m, SCUBA. coll. N.J. de Voogd, field nr.  MD11/170502/079,  17 May 2002;  RMNH Por.3054, Indonesia, Sulawesi, SW Sulawesi, Tanjung Bira, Pulau Liukan, 5.65°S 120.43°E, depth  28 m,  SCUBA, coll. N.J. de Voogd, field nr. BIR05/230501/321,  23 May 2001;  RMNH Por.5329, Indonesia, Halmahera, Maitara Maitara W, 0.7299°N 127.3624°E, depth  12 m,  SCUBA, coll. N.J. de Voogd, Ternate-Halmahera Expedition2009, field nr. TER.09/291009/080,  29 October 2009;  RMNH 8867, Taiwan, Dong YiJu, west side, outside fishing harbor, 23.2552°N 119.6671°E,  SCUBA, coll. N.J. de Voogd, field nr. PES135,  28 July 2014(orange).   Description( Figs 61a–d, 63a). The species was recently described extensively by Calcinai et al.(2006)as  Mycale (Mycale) vansoesti. We can confirm their excellent account of the species, also based on slides made from a fragment of the paratypesent to us by Dr. Barbara Calcinai. The specimens in their full-grown habitus exhibit wide-mouthed tubes, often two such tubes are found merged to a larger mass with two openings. Size may be considerable: Calcinai et al. (2006)report specimens of 40 cmhigh and 20 cmwide, with terminal vent up to 15 or 20 cm. The walls of the tube are thin (often less than 1 cmin thickness), web-like, supported by purple- or red-colored algal strands (genus  Amphiroa). Juvenile or incipient growth forms may be much smaller and basically are encrusting. These may lack an upper large opening, in stead having lateral excurrent openings giving access to the hollow interior. The surface is irregularly conulose, caused by  Amphiroastrands lifting up the surface tent-like. The skin between the strands, both on the outside and the inside of the tubes is punctured by many small incurrent and excurrent openings, of about 1 mmor less in diameter. The inner surface of the vent has also irregularly distributed larger openings, presumably oscules. Colors of larger specimens sometimes give an overall pinkish impression ( Figs 61a–b), due mostly to the algal strands, but the tissue inbetween is pale yellow, and yellow-orange colors ( Fig. 61c) are also reported frequently, especially in smaller encrusting specimens, occasionally white, rarely greenish. So far the colors are not clearly correlated to other features of the species, so we assume them to be variable. Preserved, colors are off-white or light beige ( Figs 61d, 63a). Consistency is fragile, easily damaged.  Skeleton( Figs 62a–f). The algal strands (thickness 250–400 µm) form the framework of the skeleton, but spongin-encased spicule tracts of variable thickness (commonly 30–70 µmin diameter, occasionally as thick as 200 µm) and length (may be as long as 1 mmor more) connect the algal strands to form a secondary supporting structure. Between the algal strands and the spicule tracts there is an unorganized mass of toxodragmas, anisochelae, sigmas, rare trichodragmas and single tangentially arranged megascleres. No clear ectosomal skeleton on both sides of the tube walls. The toxodragmas may form vague clusters, but sigmas and anisochelae are scattered singly in the tissue, no rosettes.  Spicules( Figs 63b–g). Mycalostyles, two categories of anisochelae, sigmas, toxas (mostly in toxodragmas), trichodragmas. Mycalostyles ( Fig. 63b,b 1), comparatively short and robust, with barely developed head, slightly fusiform, 207– 242.7–297 x 4– 6.7– 11 µm; typespecimen: 231– 267.3–297 x 4.5– 7.4– 11 µm. Anisochelae I ( Figs 63c), usually less common, narrow-shaped but otherwise normal, with both upper and lower alae developed, free part of the shaft about 40–50 %, size 17– 22.9– 30 µm; typespecimen: 17– 19.4– 22 µm. Anisochelae II ( Figs 63d), usually more common, comparatively slightly more reduced with upper and lower alae pointed towards each other, 10– 13.4– 19 µm; typespecimen: 10– 13.3– 16 µm. Sigmas ( Fig. 63e), usually very common, thin, asymmetrically curved, the endings look roughened under SEM, but no definite spines were observed, 16– 24.9– 30 µm; typespecimen: 19– 24.8– 30 µm. Toxodragmas ( Figs 63f,f 1), extremely common, consisting of an intertwined double-pack of individual thin raphide-like toxas (less than 1 µmin thickness), leaving a characteristic eye-like central opening, 33– 42.5–51 x 4– 6.6– 10 µm; typespecimen: 34– 43.9–51 x 4– 7.4– 10 µm.   FIGURE 61.  Mycale (Kerasemna) humilis( Thiele, 1903), in situand preserved images from Indonesia, a–b, ZMA Por. 14523, from Bunaken Island, N Sulawesi, (photos B.W. Hoeksema), c, RMNH Por. 2617 from SW Sulawesi (photo N.J. de Voogd), d, ZMA Por. 08953 from Bahuluang Island, Salayar, preserved habitus (scale bar = 1 cm).   FIGURE 62.  Mycale (Kerasemna) humilis( Thiele, 1903), a–d, light microscopic images from histological slides of the holotype of  Biemna humilis, ZMB3203, from Ternate, Indonesia, a, algal strand encrusted by skeletal tracts and microscleres, b, detail of a, c, massed presence of toxodragmas in the tissue, d, microscleres, including sigmas, toxodragmas, anisochelae I (arrow I) and anisochelae II (arrow II), e–f, light microscopic images of ZMA Por. 16382 from Ambon, Indonesia, e, skeletal structure of algal strands and interconnecting spicule tracts, f, detail of e. Trichodragmas ( Fig. 63g), not common, consisting of a small package of straight raphides, 7– 11.8–17 x 3– 6.6– 10 µm; typespecimen: 9– 11.9–15 x 3– 6.4– 9 µm.   Distribution and ecology( Fig. 64). Indonesia, Singapore, Papua New Guinea, Palau, Taiwan, Madagascar, Kenya,?Western India, on reefs down to  36 m.More ecological information is provided in Calcinai et al.(2006).   Remarks. We re-examined original slides of Thiele’s  Biemna humilisand found abundant anisochelae I and II, apparently overlooked by Thiele. In most aspects,  Biemna humilisconforms with what is so far known as  Mycaleaff. cockburniana sensu Van Soest 1990and  Mycale (Mycale) vansoesti Calcinai et al., 2006. Thiele’s material was a blade-like encrustation, not an elaborate wide-tubed specimen, but in spiculation and presence of  Amphiroastrands there is complete conformity. Calcinai et al.’s name is a primary junior homonym of  Mycale (Grapelia) vansoestiHajdu, 1995, which has priority. Calcinai et al. 2017proposed  Mycale (Mycale) corallinato replace  M. (M.) vansoestiCalcinai et al., because junior primary homonyms are permanently invalid (ICZN Art. 57.2). Van Soest & Hooper (2020: 63) were unaware of this replacement name (which was proposed in a Supplementary file, and at the time was not picked up by the World Porifera Database) and proposed  Mycale calcinaiaeas a replacement name. Both names are junior synonyms of  Mycale (Kerasemna) humilis( Thiele, 1903)  comb.nov.   FIGURE 64.  Mycale (Kerasemna) humilis( Thiele, 1903), approximate distribution of specimens studied (green squares) and literature records (pale green dots). Squares and dots may represent several close collecting localities. Calcinai et al.’s description does not entirely conform to our above description as it omitted reporting the small trichodragmas, which were found in all our specimens, including Calcinai’s paratype. Because they are quite small and not at all very common, we assume that they were overlooked by Calcinai et al. Although Pulitzer-Finali (1993)reported the present species from Kenyaas  Desmacella humilis, he pointed out in the discussion that it shared the toxodragmas with his Australian  Kerasemna tenuityla. Subsequently, Kelly in Richmond et al. 2013, used the combination  Kerasemna humilisfor our species. We confirm here the presence of the species in the Western Indian Ocean by reporting a specimen from Madagascar. The spicule shape and sizes (mycalostyles 244–249 x 6–7.5 µm, anisochelae I 22–25 µm, anisochelae II 17–19 µm, sigmas 21–29 µm, toxodragmas 45–50 µm, and trichodragmas 12–17 µm) conform to those of the numerous specimens we report from the Western Pacific. Apparently orange colored specimens are more common there, as both our specimen, Pulitzer-Finali’s specimens and Richmond’s specimen are reported to have that color. Still, orange and yellow specimens were also reported from Indonesia(see Fig. 61c), Singapore, Taiwanand Papua New Guinea. The coralline algae found associated with the species recognized so far appear to be mostly  Amphiroaspec., at least in the pink, purple, or pale yellow-white forms. Possibly, the association is thus obligatory, but this may be only for these forms. Yellow-orange specimens may have a different algal associate (cf. Calcinai et al.2006). Pulitzer-Finali’s (1993) Kenyaand Zanzibarrecords mention the presence of toxodragmas and sigmas, but do not report anisochelae. It is possible that the specimens do not contain anisochelae and belong to  M. (K.) tenuiylarather than to  M. (K.) humilis.  Dendy’s (1916)report of a deviating  Desmacella tubulataappears on paper to be a likely record of the present species from Western India, as Dendy mentions ‘toxa arranged in a sheaf or toxodragma’. This will need to be reexamined for certainty.   Mycale cockburniana Hentschel, 1911and its variety albanensis Hentschel, 1911, generally shares the spicule complement with the present species: mycalostyles 192–256 x 3–4 µm, two size categories of anisochelae 21–27 µmand 13–16 µm, thin sigmas 22–25 µm, and trichodragmas 25–30 µm. The habitus is encrusting and contains ingrown ‘Pflanzentheile’, adding to the similarity. The main difference is the absence of the peculiar toxodragmas. The skeleton is described as conforming to subgenus  Carmia(cf. above).   Kerasemna tenuitylaPulitzer-Finali, 1982(see below) is a close relative, differing mostly in the absence of anisochelae. We maintain this as a separate species for the time being. 3026466452 ZMA Indonesia Por. 36 -7.1833 Pulau Sarassa 5511 118.2 Postillion Islands 97 98 1 Nusa Tenggara Timur 3026466765 ZMA Komodo, NE Indonesia 3 -8.4833 East 7 119.5683 Por. 97 98 1 Nusa Tenggara Timur 3026466489 [429,950,1501,1528] R W. M. van Soest & Indonesian-Dutch Snellius Indonesia 97 98 1 Nusa Tenggara Timur 3026466716 [959,1368,1501,1528] II Expedition Indonesia 97 98 1 Nusa Tenggara Timur 3026466400 1984-09-19 II Indonesia 97 98 II/02 1 Nusa Tenggara Timur 3026466855 ZMA Indonesia 7 Taka Karlarang Por. 97 98 1 Sulawesi Utara 3026466680 [480,1005,1573,1600] R W. M. van Soest & Indonesian-Dutch Snellius Indonesia 97 98 1 Sulawesi Utara 3026466408 [1014,1427,1573,1600] II Expedition Indonesia 97 98 1 Sulawesi Utara 3026466722 [151,553,1609,1636] 1984-09-27 III Indonesia 97 98 III/11 1 Sulawesi Utara 3026466538 ZMA SW Salayar Indonesia 13 -6.45 Por. 782 120.43 97 98 1 Sulawesi Utara 3026466444 [769,1282,1645,1672] R W. M. van Soest & Indonesian-Dutch Snellius Indonesia 97 98 1 Sulawesi Utara 3026466455 II Expedition Indonesia 97 98 1 Sulawesi Utara 3026466644 [408,873,1681,1708] 1984-09-30 IV Indonesia 97 98 IV/24 1 Sulawesi Utara 3026466652 ZMA M. C. Diaz Papua New Guinea Por. 97 98 1 3026466472 1996-09-22 ZMA H. Erhardt Indonesia 1.6132 Bunaken Island 7 124.7797 Por. 97 98 1 Sulawesi Utara 3026466414 ZMA Indonesia Por. 6 Samalona Spermonde Archipelago 97 98 1 Sulawesi Utara 3026466807 [700,1231,1825,1852] 1997-05-06 SA Indonesia 97 98 1 Sulawesi Utara 3026466922 ZMA Indonesia Por. 18 -1.6317 Siladen Island 7 124.8053 Bunaken 97 98 1 Sulawesi Utara 3026466441 ZMA Nosy B Madagascar 7 Crater Bay Por. 97 98 1 3026466518 [823,1432,1933,1960] 1963-12-21 SCUBA J. H. Stock Madagascar 97 98 1 3026466707 [151,989,1969,1996] ZMA Indonesia 20 Tanjung Setan Por. 97 98 1 Maluku Utara 3026466448 1995-08-20 SCUBA S. Weinberg Indonesia 97 98 1 Maluku Utara 3026466606 RMNH Palau Por. 8 98 99 7.3167 Ngeteklou 7 134.5167 Ngerikuul Pass 97 98 1 Koror 3026466493 [783,1191,151,177] SCUBA Voogd Palau 98 99 1 Koror 3026466527 2005-05-12 KOR Palau 98 99 KOR02 1 Koror 3026466478 RMNH Palau Por. 7.3167 Ngeteklou 7 134.5167 Ngerikuul Pass 98 99 1 Koror 3026466601 [764,1189,223,249] SCUBA Voogd Palau 98 99 1 Koror 3026466702 2005-05-21 KOR Palau 98 99 KOR02 1 Koror 3026466314 RMNH Palau Por. 7.3167 Ngeteklou 7 134.5167 Ngerikuul Pass 98 99 1 Koror 3026466723 [724,1152,295,321] SCUBA Voogd Palau 98 99 1 Koror 3026466877 2005-05-21 KOR Palau 98 99 KOR02 1 Koror 3026466459 [281,1431,330,357] RMNH Bali, N Palau Por. 15 -8.6736 Desa Buyuk 7 115.5436 Nusa Penida 98 99 1 Koror 3026466754 2001-04-21 SCUBA N. J. de Voogd & Bali-Lombok Strait Expedition Palau 98 99 1 Koror 3026466827 RMNH Padang Bai, E Palau Por. 15 -8.5294 Tanjung Sari 7 115.5131 Bali 98 99 1 Koror 3026466357 2001-04-08 SCUBA N. J. de Voogd & Bali-Lombok Strait Expedition Palau 98 99 1 Koror 3026466491 RMNH Singapore Por. 12 1.2308 Monkey Island 7 103.8365 Pulau Tekukor 98 99 1 3026466921 [294,1216,511,538] 2006-04-04 SCUBA N. J. de Voogd Singapore 98 99 1 3026466554 RMNH Indonesia Por. 25 -5.65 Pulau Liukan 783 120.43 Tanjung Bira 98 99 1 Sulawesi Utara 3026466879 2001-05-23 SCUBA N. J. de Voogd Indonesia 98 99 1 Sulawesi Utara 3026466651 RMNH SW Siladen Island Indonesia 15 1.6167 Por. 7 124.7833 98 99 1 Sulawesi Utara 3026466790 [1054,1432,618,645] 2002-05-17 MD Indonesia 98 99 MD11 1 Sulawesi Utara 3026466334 [151,1431,654,681] RMNH Indonesia Por. 28 -5.65 Pulau Liukan 783 120.43 Tanjung Bira 98 99 1 Sulawesi Utara 3026466509 [151,961,690,717] 2001-05-23 SCUBA N. J. de Voogd Indonesia 98 99 1 Sulawesi Utara 3026466374 RMNH Maitara Maitara W Indonesia 12 0.7299 Halmahera 7 127.3624 Por. 98 99 1 3026466364 2009-10-29 SCUBA N. J. de Voogd & Ternate-Halmahera Expedition Indonesia 98 99 1 3026466742 RMNH Taiwan 23.2552 Dong YiJu 7 119.6671 98 99 RMNH 8867 1 3026466339 [598,1381,798,825] 2014-07-28 SCUBA N. J. de Voogd Taiwan 98 99 1