Dercitus Gray 1867

(Figs 8A, 9A). Sponge encrusting and agglutinating calcareous fragments, colour dirty white. Lateral size approx. 5×3 cm. The holotype now consist of three fragmented pieces, the paratype is 1.5×1.5 cm. Consistency crumbly. Skeleton: a confused mass of calthrops with a crust of microscleres at the surface. Spicules: calthrops (no dichocalthrops) and sanidasters. Calthrops (Figs 8B, 9B–C), often with bifid or bluntly rounded cladi, occasionally five-claded, in a wide size range but upper size relatively large, cladi length and thickness 92–299.8–426 × 8–38.6–55 µm (in holotype) and 36–224.9–480 × 6–28.6–60 µm, cladomes 126–462.6–618 µm (holotype) and 61–300.4–810 µm (paratype). Sanidasters (Figs 8C, 9D), relatively uniform in size and spination, relatively small: 11–12.6–17 µm (holotype) and 12–17.3–21 µm (paratype).

(Fig. 10A). Encrusting sponge, agglutinating and consolidating limestone fragments (dead corallines and serpulids), pale yellow-coloured, with cartilaginous consistency. Growing together with a yellow-colouredChaetodoryxsp. Size of agglutinated mass approx. 4×2 cm. Skeleton: a confused mass of dichocalthrops with a thin crust of sanidasters. Spicules: dichocalthrops (no calthrops), sanidasters. Dichocalthrops (Fig. 10B) relatively large, regularly shaped, with limited size variation, protocladi more or less uniform in smaller and larger spicules, but deuterocladi longer in larger ones: protocladi 42–48.2–56 × 9–21.6–35 µm, deuterocladi 23–106.8–204 × 4–17.2–29 µm, rhabdomes 71–170.6–252 × 8–21.0–31 µm, cladomes 132–294.6–475 µm. Sanidasters relatively small, little variation in spination and ornamentation, 11–13.3–16 µm.

According toTendal (1969)the sponge formed an irregular mass of 2×5×4 mm, situated in a crevice in a dead piece of coral. Smooth surface. Colour dark grey, oscules and pores not visible. Consistency hard. The material available to us consisted of a tiny fragment, approx. 1 mm3, half of which was sacrificed for SEM and a residue spicule slide. Skeleton: unknown but presumably confused, with an ectosomal cover of microscleres. Spicules: calthrops and dichocalthrops megascleres in approximately equal quantities, sanidasters. Calthrops (Fig. 12A), with cladi occasionally crooked or bifid at the apex, size relatively uniform with few smaller spicules, cladi 96–222.7–258 × 19–31.2–37 µm, cladome 186–347.1–420 µm. Dichocalthrops (Fig. 12B), with smaller sizes normal shaped, but characteristically with very short protocladi and long conical deuterocladi when larger, protocladi 19–26.5–30 × 13–25.2–42 µm, deuterocladi 55–112.5–192 × 9–20.2–31 µm, rhabdomes 58–84.6–132 × 11–13.6–21 µm, and cladomes 129–248.4–361 µm. Sanidasters (Fig. 12C), relatively thick, pointed-fusiform at low magnifications, in SEM mostly with blunt endings, relatively uniform in size and shape, 15–16.9–21 × 3–3.6–4 µm.

Slippery smooth encrustation on dead coral (Fig. 13A); the present material (upper part ofFig. 13A) consists of three fragments of 12×10, 8×8 and 8×5 mm, of approx. 1–2 mm in thickness. The holotype (lower part ofFig. 13A) is a largerfragment of 7×6 cm (not examined). Colour bright red when alive, darker red in alcohol. Consistency gum-like, easy to cut. Skeleton: a confused mass of short-shafted triaenes and sanidasters. Spicules: calthrops-like short-shafted triaenes, dichocalthrops and sanidasters. Calthrops (Figs 13B, D) showing a clear rhabd, longer than the cladi, which are frequently curved or undulated or bifid. Cladi 138–166.7–186 × 12–22.5–28 µm, cladomes 207–266.4–330 µm in diameter, rhabds 230–245.9–270 × 24–27.2–30 µm. Regular symmetrical dichocalthrops (Figs 13C–D) occur less frequently; protocladi 18–29.0–35 µm and deuterocladi 57–68.1–105 × 12–14.1–18 µm, rhabdomes 70–141.0–180 × 12–20.7–30 µm, cladomes 143–197.9–266 µm. Sanidasters (Fig. 13E) have an overall short and squat shape. They tend to be amphiaster-like with frequently more heavily spined apices; spines usually with secondary spines. Size 12–13.3–15 × 2–2.85–3.5 µm.

Blackish grey lobate mass (Fig. 15A), approx. 20×15×10 cm in size, surface in places speckled white by ?coral sand and at the base the specimen is encrusted by a bluish sponge (Haliclona). Oscules prominent on the summit of lobes, approx. 0.5 cm in diameter. Consistency firm, compressible. The preserved specimen is broken into two similar sized masses (Figs 15B, 16A). The black colour is maintained in alcohol and has strongly darkened the fluid and the labels. Skeleton: difficult to study in the preserved condition due to the intense black colour, but structure is dense and unorganized, with a dense cover of microscleres at the surface. Spicules: calthrops, sanidasters and compressed spheraster-like microscleres (pseudasters); a few oxeas are present, but these belong to the encrustingHaliclona. Calthrops (Fig. 16B), generally regular in shape and cladi number, occasionally three-claded or five-claded; size highly variable, cladi 25–151.4–280 × 5–17.2–35 µm. Sanidasters (Fig. 16C) of extreme variability in shape, long thin with short spines, thicker with prominent stubby spines and squat warty ones, with many intermediates; size 19–29.1–42 × 1–5.1–10 (spines 0.5–2.2–4.5 µm). Compressed sanidasters (pseudasters) (Fig. 16D), globular or oval with very short rays (usually less than 0.5 µm), diameter 8–11.4–15 µm.

Holotype (Fig. 17A) is a blackish brown fragment of 3.5×3×1 cm (live colour also noted as black). Surface lumpy but smooth, shiny. Consistency firm, compressible. Skeleton: at the surface a crust of microscleres, overlying a dense confused mass of calthrops. Spicules: calthrops, sanidasters, compressed sanidasters (pseudasters). Calthrops of holotype (Fig. 17B) equiangled, regular, 105–170.8–223 × 14–20.7–28 µm (cladomes 182–286.3–365 µm); of the paratype (Fig. 18A), equiangled, some with ‘hooked’ apices, 33–177.2–252 × 5–23.9–37 µm (cladomes 63–319.0–451 µm). Sanidasters of holotype (Fig. 17C) long, relatively slim, 27–28.8–31 × 2.5–3.9–4.5 µm; of the paratype (Fig. 18B), similarly slim, 19–25.7–33 × 2–4.5–6 µm. Compressed sanidasters of the holotype (Fig. 17D), mostly elongated-oval, only few are more or less globular, 7.5–10.1–15 µm; of the paratype (Fig. 18C), similarly oval or even shaped as ‘double’ asters, 7–9.3–14 µm.

Small soft patches of a brown-red colour insinuating in three coral fragments (Fig. 21A), occupying spaces less than 5 mm in diameter. No remarkable macroscopical features. Skeleton: Confused mass of calthrops and microscleres, no explicit structure. Spicules: Calthrops, sanidasters and microrhabds. Calthrops (Figs 21B–C) with gradually curved cladi, the apices of the cladi variously sharply pointed or blunt, occasionally displaying three-claded forms. Cladi: 60–119.2–174 × 9–14.9–21 µm, cladomes: 96–192.7–264. Sanidasters (Fig. 21D) variable in shape and size, varying from thin amphiaster-like forms with clusters of spines at the ends or at least separated in the middle by a stretch with few spines, to fusiform or fat simple spined forms, size 16–20.8–26 × 1–2.1–3.5 µm. Microrhabds (Figs 21F) short and thick, almost smooth, with only scattered very short spines, 5–7.7–9 × 3–4 µm. The microrhabds very likely derive from the sanidasters as there are some stages (Fig. 20E) which appear intermediate.

Thin leathery-rubbery encrustation (Fig. 22A) cementing coral rubble and filling crevices in coral material. Colour (alcohol) pale orange brown. Surface smooth, not encrusted, no oscules apparent; interiorly with a different more mushy texture. Size 2.5×2×0.5 cm. Skeleton: an ectosomal crust of microscleres overlying a mixture of microscleres and dichocalthrops embedded in largely organic choanosome with relatively low spicule density. Spicules: dichocalthrops, sanidasters and compressed fat sanidasters. Dichocalthrops (Fig. 22B) relatively small and delicate, with curved pointed deuterocladi; protocladi, rather uniform in length, more variable in thickness, 24–26.5–30 × 5–8.0–11 µm; deuterocladi variable in length, 12–26.1–39 × 3–5.6–9 µm; rhabd short and pointed, 36–75 × 6–9 µm; cladome 75–101.1–144 µm. Sanidasters in two categories, long-and-thin (Fig. 22C) and short-compressed (Fig. 22D); the latter are ovoid, not compressed to the extent that they form asters. Thin sanidasters, 12–13.9–16 × 1.5–2.05–3 µm, short-compressed sanidasters 7–11.0–13 × 4.5–5.6–7.5 µm.

Senegal, Mauritania, possibly (Eastern) Mediterranean.

So far with certainty known only from the type locality. Possibly, Topsent’s 1928 record ofDercitus plicatusfrom Boavista also belongs to this species.

Known only from the Fijian type locality.

Known only from the Bahamian type locality.

So far known only from the type locality E of Kalimantan.

Both specimens came from nearby locations, so the distribution so far appears limited to offshore Japan.

So far known only from the island of Aruba, Southern Caribbean.

Known only from the type locality in Eastern Indonesia.