Pachyseris inattesa Benzoni & Terraneo

Terraneo, Tullia I., Berumen, Michael L., Arrigoni, Roberto, Waheed, Zarinah, Bouwmeester, Jessica, Caragnano, Annalisa, Stefani, Fabrizio & Benzoni, Francesca, 2014, Pachyseris inattesa sp. n. (Cnidaria, Anthozoa, Scleractinia): a new reef coral species from the Red Sea and its phylogenetic relationships, ZooKeys 433, pp. 1-30 : 7-10

Taxon classification Animalia Scleractinia Agariciidae

Pachyseris inattesa Benzoni & Terraneo sp. n. Figures 4-7, 10a, c, e, 11 b–e

Leptoseris tenuis Van der Horst, 1921 (partim). Scheer and Pillai 1983: figs 7-11.

Leptoseris foliosa Dinesen, 1980. Sheppard and Sheppard 1991: fig. 85, Plate 58; Veron 2000: fig. 8.

Material examined.

Holotype: RMNH Coel. 41613 (Figures 4d, 6 b–d). Type Locality: Al Lith, Saudi Arabia (MV Dream-Master, KAUST Biodiversity Cruise to the Farasan Banks and Farasan Islands), 20°07.690'N, 40°12.513'E, 3 March 2013, coll. F. Benzoni.

Corallum: The specimen is 1.5 cm high from the base in its original growth position, and 7.5 × 5.2 cm wide. The holotype is oval-shaped, attached at the centre with free margins and sunken in the central part (Figures 4d, 6b). At the opposite ends of its largest diameter the corallum margins bend in different directions with respect to the plane of the central encrusting part (upwards at the left-hand side and downwards at the right-hand side of Figure 6b). The corallum surface is irregularly undulated due to the presence of well-developed carinae, which are symmetrical and thick in the central part (Figure 6d) and become increasingly shorter, lower, and more inclined towards the margins (Figure 6c).

Calices: Arranged in short rows, mostly distinct (Figure 6d) especially towards the margins where the series become shorter (Figure 6c). Calices and series of calices are arranged parallel to each other, concentric and separated by wide and rounded carinae with variable vertical development and inclination with respect to the corallum surface (Figures 4d, 6c). Where carinae separate, single calices or short series become distinct. In these cases, short carinae can resemble proximal cushions, the typical features forming in the agariciid genus Leptoseris when the inner or proximal side of an inclined corallite is raised into a cushion-like structure ( Dinesen 1980).

Columella: Well-developed, sitting deep in the fossa (Figure 6d) made by one or more processes derived from the inner end of the radial elements.

Radial elements: Radial elements are continuous across the carinae, regularly spaced and equal. Lateral faces bear regularly distributed, parallel lines of clumped granules (Figure 7e). The upper margin of the radial elements is minutely beaded and typically attains a zigzag pattern with ornamentations at the angles (Figure 7f).

Color: The in vivo color was light brown with the top of the collines and the margins of the colony paler.

Other material

(MV Dream-Master, KAUST Biodiversity cruises, Saudi Arabia): KAUST SA004, Al Lith (KBEF), 20°07.690'N, 40°12.513'E, 3 March 2013, coll. F. Benzoni; KAUST SA426, Qita al Kirsh, 22°25.597'N, 38°59.769'E, 18 March 2013, coll. F. Benzoni; KAUST SA429, Qita al Kirsh, 22°25.597'N, 38°59.769'E, 18 March 2013, coll. F. Benzoni; KAUST SA678, Al Wajh (KBEA), 25°23.515'N, 36°41.035'E, 25 September 2013, coll. F. Benzoni; KAUST SA860, Shibb al Hab (KBEA), 27°49.003'N, 35°06.397'E, 28 September 2013, coll. F. Benzoni; KAUST SA887, Jazirat Burcan (KBEA), 27°54.356'N, 35°03.555'E, 28 September 2013, coll. F. Benzoni; KAUST SA1284, Fsar, 22°13.779'N, 39°01.730'E, 20 October 2013, coll. F. Benzoni; KAUST SA1293, Fsar, 22°13.779'N, 39°01.730'E, 20 October 2013, coll. F. Benzoni and J. Bouwmeester; KAUST SA1300, Fsar, 22°13.779'N, 39°01.730'E, 20 October 2013, coll. F. Benzoni and J. Bouwmeester; KAUST SA1301, Fsar, 22°13.779'N, 39°01.730'E, 20 October 2013, coll. F. Benzoni and J. Bouwmeester; KAUST SA1305, Fsar, 22°13.779'N, 39°01.730'E, 20 October 2013, coll. F. Benzoni and J. Bouwmeester.

Variation of skeletal structures.

Average colony size is around 15 cm in diameter (Figure 4). The largest colony observed in the field was 25 cm across (Figure 11b). Corallum generally encrusting at the centre with foliose margins, thicker in colonies grown in well-lit environments and thinner in those from deeper and lower light conditions. Calices always distinct and arranged in series in most specimens although the length of the series can be very variable within and between specimens (Figures 4-6) and single calices can be also observed (Figure 6g). Carinae are always rounded, however they show much variation in height and width (Figure 4). Examples of the two ends of the wide variation range of the development of carinae in this species are provided in Figure 5. Columella always present, sitting low in the fossa, made of one or multiple spatula-shaped processes extending from the inner end of the radial elements (Figures 6 a–d). No dissepiments were observed between the inner ends of the radial elements and the processes forming the columella in calices in series or alone (Figures 7 a–b). Although radial elements are generally equal (Figures 6 f–g, 7 a–b) they can be unequal in some specimens (Figure 6e). Their faces’ ornamentation consists of parallel lines of clumped granules (Figures 7, 10a, c, e). Clumps of granules can fuse laterally to form short ledge-like features (Figure 10e), however these never develop into menianae sensu stricto. The upper margin of the radial elements is minutely beaded (Figures 7f, 10e) and typically attains a zigzag pattern with clumps of granules at the angles (Figure 7f).

Field characteristics and coloration.

In well-lit conditions and when growing on a horizontal substrate, this species tends to have a wrinkled appearance due to well-developed carinae. In colonies growing on inclined substrate and shaded conditions the carinae are less developed and the corallum surface can attain a smooth or slightly undulating surface. The coloration ranges from a grayish beige (Figures 4b, c, h, 5 a–b) to brown with some areas having a greener tinge (Figures 4a, d–g, 5 c–d).

Ecology.

Pachyseris inattesa sp. n. was recorded from different reef habitats between 10 and 35m depth. It grows on exposed reef slopes as well as in underneath overhangs and small caves.

Occurrence.

This species has been sampled along the Saudi Arabian coast in the northern and central Red Sea (Figure 8). It was not recorded in the Farasan Islands, nor further south in the Kamaran Islands, Yemen. To date, its distribution appears to be limited to the Red Sea.

Affinities.

Among its congeners, this species bears most resemblance to Pachyseris speciosa . However, with respect to the macro-morphology of the corallum, the corallites, and in corallite arrangement, this species is similar to and has been previously misidentified as Leptoseris foliosa .

Etymology.

Inattesa means “unforeseen” in Italian and stems from the initial bewilderment of the authors once they first examined the skeleton of the new species under a microscope.