Lissodendoryx (Anomodoryx) incrustans sp.nov. Aguilar-Camacho, Carballo & Cruz-Barraza

(Figs 4, 5)

Material examined

Holotype: LEB-ICML-UNAM-1393, El Requesón (Bahía Concepción, Baja California Sur [BCS]), 26°38’38’’N, 111°49’53’’W, 29/X/2006, 9 m depth.

Paratypes: LEB-ICML-UNAM-449, Isla Pájaros (Mazatlán, Sinaloa), 23°15’29’’N, 106°28’25’’W, 02/II/2002, 4 m depth.

Etymology: The term ‘incrustans’ refers to the encrusting morphology of this species.

Diagnosis: Red encrusting sponge, with a choanosomal anisotropic reticulum formed by primary multispicular fibres, interconnected by secondary paucispicular tracts. Spicules are tylotes with smooth heads. Tylotes length: 150–230 μm; head diameter: 2.5–5 μm. Sigmas in ‘C’ or ‘S’-shaped from 15–40 μm in length, and arcuate isochelae from 15–20 μm in length.

Description: Thinly encrusting sponge 1–3 cm long and 2–4 mm thick (Fig. 4A, B). The surface is smooth and translucent in preserved specimens. The oscula and ostia are not visible asser fixation. The consistency is flexible and difficult to tear. The colour in life is red, pale in preservation.

Skeletal characteristics

Skeleton: There is no special ectosomal skeleton. The choanosomal frame is an anisotropic reticulum (Fig. 4C), formed by primary multispicular fibres (30–60 µm thick) enclosing tylotes, interconnected by secondary bispicular fibres (5–10 µm thick). Microscleres are dispersed with no particular organization.

Spicules: Megascleres are exclusively tylotes, which are slender, straight, or slightly curved at the centre, or even flexuous, with smooth and pronounced heads. Tylotes length: 150–(190.7)– 230 µm; shass diameter: 2.5–(2.65)–5 µm; head diameter 3.8– (5.2)–7.5 µm (Fig. 5A, B; Table 3). Microscleres are in ‘C’- or ‘S’-shaped sigmas: 15–(34.1)–40 µm (Fig. 5C; Table 3), and arcuate isochelae: 15–(16.4)–20 µm (Fig. 5D; Table 3).

Distribution and habitat

Lissodendoryx (Anomodoryx) incrustans sp. nov. was found in Isla Pájaros, Mazatlán Bay (Sinaloa) and in El Requesón, Concepción Bay (Baja California Sur) (Fig. 1). The species is common in clear shallow waters, living on dead corals and rocky substrates exposed to high water movement. The depth range is between 4 and 8 m.

Remarks: Lissodendoryx (Anomodoryx) incrustans sp. nov. has tylotes, sigmas, and arcuate chelae. The morphologically most similar species is Lissodendoryx (Anomodoryx) dendyi (Whitelegge, 1901), which is a massive yellow sponge described from Australia. It has tylotes (150–250 × 2.5–9 µm), arcuate chelae (18–25 µm), and sigmas (35–40 µm). The spicule measurements are like those in Lissodendoryx (Anomodoryx) incrustans sp. nov. However, we think that they are different species based on geographical location, colour, and morphology (Mexican Pacific, red encrusting in Lissodendoryx (Anomodoryx) incrustans sp. nov., and Australian coast, yellow massive in L. (A.) dendyi .

Figure 5. SEM images of spicules of Lissodendoryx (Anomodoryx) incrustans sp. nov. A, Tylotes; B, tylotes head detail; C, sigmas; D, arcuate isochelae.

For comparison, other species in the subgenus Anomodoryx are:

Lissodendoryx (Anomodoryx) amphispinulata Rützler, Piantoni & Díaz, 2007, which is a massive grey sponge described from the Gulf of Mexico, with tylotes (236.3–267 × 4.5–6.4 µm), acanthotylotes (204.2–226.9 × 5.5–6 µm), arcuate chelae (23.9–27.3 µm), and sigmas (15.3–16.2 µm). The microscleres are longer in Lissodendoryx (Anomodoryx) incrustans sp. nov. than in L. (A.) amphispinulata .

Lissodendoryx (Anomodoryx) sigmata (de Laubenfels, 1949) is a massive yellow sponge described from the Caribbean with tylotes (189.9–257.1 × 3.7–6.7 µm), arcuate chelae in two categories (I. 20.6–43.7 µm; II. 12–16.1 µm), and sigmas in two categories (I. 43.8–52.4 µm; II. 11.5– 13.4 µm) (Rützler et al. 2007). Lissodendoryx (A.) sigmata has two categories of arcuate chelae and sigmas, whereas Lissodendoryx (Anomodoryx) incrustans sp. nov. has a single category for these microscleres.

Lissodendoryx (Anomodoryx) vulcanus Cavalcanti, Santos & Pinheiro, 2014, is a brownish-purple volcano-shaped sponge described from Brazil. This is the only species of the subgenus Anomodoryx bearing raphides in the skeleton.