Pocillopora acuta

Schmidt-Roach, Sebastian, Miller, Karen J., Lundgren, Petra & Andreakis, Nikos, 2014, With eyes wide open: a revision of species within and closely related to the Pocillopora damicornis species complex (Scleractinia; Pocilloporidae) using morphology and genetics, Zoological Journal of the Linnean Society 170 (1), pp. 1-33 : 17-21

POCILLOPORA ACUTA ( LAMARCK, 1816) ( FIGS 8 , S2)

SYNONYMY

Pocillopora acuta Lamarck, 1816 p. 274

Pocillopora bulbosa Ehrenberg, 1834 p. 351 (p 127)

Madrepora damicornis 1766 p . 334, Esper (1791) pl. 46A

Pocillopora apiculata Ehrenberg, 1834 p. 351

Pocillopora cespitosa Dana, 1846 p. 525 , pl. 49, fig. 5, 5a

Pocillopora subacuta Edwards & Haime, 1860 p. 303

Taxonomic history

Pocillopora acuta Lamarck (1816) defines the genus Pocillopora (type specimen Fig. 8E ). Esper (1791) illustrated a colony of Pallas’s (1766) Madrepora damicornis type 8F as an elongate, fine branching morph, later in literature commonly referred to as Ehrenberg’s (1834) species Pocillopora bulbosa . Dana’s (1846) interpretation of this elongate morphology as P. bulbosa led to much confusion in consecutive descriptions. However, Lamarck (1816) referred to Esper’s (1791) illustration as representing P. acuta . The type specimen of P. bulbosa (a relatively small fragment) shows a compact morphology and does not match what has been referred to as P. bulbosa in the literature. Furthermore, Ehrenberg’s collection contains a specimen labelled P. acuta , which matches Lamarck’s description. Thus, P. bulbosa represents a junior synonym of P. acuta . In addition, Ehrenberg (1834) described a moderately compact morph of this taxon as Pocillopora apiculata ( Fig. 8H ). Dana (1846) described and illustrated this species as P. cespitosa (plate 49, fig. 5).

Holotype

MNHN-IK-2010-792 ( Fig. 8E ). Origin: Indian Ocean.

Material studied

MTQ samples: G37619 China Sea , Pratas Reef (21°50′N, 117°00′E) ; G33370 Orpheus Island (18°36′S, 146°29′E) ; 51948 Gulf of Aden, Yemen (12°47′N, 045°03′E) ; G33627 Shrimp Reef , QLD, Australia (1853′S, 14805′E) ; G33376 Fantome Island (Palm Islands), QLD, Australia (15–20 m) (18°41′S, 146°31′E) . G33375 Houghton Island , QLD, Australia (14°31′S, 144°58′E) . G35114 Flinders Reef (Coral Sea), 5 m (17°40′S, 148°20′E) . Further material: Orpheus Island (2 specimens), Lizard Island (12 specimens) (see Table S1) .

Corallum

Compact in exposed environments to elongate in sheltered environments ( Fig. S3 ). Cespitose, much branched, branches mostly round and rarely flattened. This species shows consistently pointy branches, with sharp tips, a feature that differentiates it from its sister taxon P. damicornis . Two morphological variants can be differentiated, which are found in exposed and sheltered environments, respectively. Pocillopora acuta in sheltered environments is characterized by elongate, fragile, slender branches almost approaching Seriatopora hystrix Dana, 1846 ( Fig. S3E–J ) but no seriate cells. Pocillopora acuta in exposed environments resembles P. apiculata Ehrenberg, 1834 . The corallum is compact to compressed, but still cespitose with crowded branches ( Fig. S3A–D ).

Corallites and coenosteum

Calices are 0.7–1.3 mm in diameter, often oval due to the narrow, slender growth. The columella is flat and ornamented with short spinulae, septa are only rudimentarily developed, often only indicated by spinulate septa teeth and arranged hexamerally in two equally developed cycles. The coenosteum is ornamented sparsely to densely (mostly towards the branch endings) with short spinulae.

Colour and pigmentation of the live colony

Pale (sometimes greenish) with characteristic darker pigmentation surrounding oral opening of polyps (giving appearance of brown rings outlining polyps).

Habitat and biology

In the Central and Northern Great Barrier Reef this species is common on the leeward site of the reefs, but compact morphs can also be found in exposed environments. It occurs in lagoons, back reef habitats to the deeper (> 12 m) habitats of the reef slope. In sheltered habitats the fine morphology is exhibited. At One Tree Island in the southern Great Barrier Reef this species was not recorded. Pocillopora acuta releases brooded asexual larvae after new moon ( Schmidt-Roach et al., 2012a), supporting earlier observations of brooding in this species ( Marshall & Stephenson, 1933). Although it has not been observed to spawn, it is expected to have a mixed mode of reproduction as observed in its sister species P. damicornis ( Schmidt-Roach et al., 2012b) .

Remarks

A rapid genetic assay for the identification of this genetic lineage on the Great Barrier Reef has been recently developed and successfully employed in a population genetic study, further confirming reproductive isolation of this lineage from P. damicornis ( Torda et al., 2013) .

Distribution

Specimens were identified from various locations along the Great Barrier Reef, but no colonies were observed at One Tree Island in the Southern Great Barrier Reef. Sequences from public databases indicate a wide distribution of this species reaching from the central Pacific to the Indian Ocean; it seems to be absent in the Tropical Eastern Pacific as the genetic lineage was not identified in the region (see Flot et al., 2010; Pinzón & LaJeunesse, 2010; Pinzón et al., 2013) ( Fig. 5 ).

POCILLOPORA ALICIAE SCHMIDT- ROACH ET AL., 2013

( FIGS 9 , S 4 )

Taxonomic history

Pocillopora aliciae was previously considered a temperate ecomorph of P. damicornis (e.g. Veron &

Pichon, 1976), but was recently described as a sepa-

rate species ( Schmidt-Roach et al., 2013).

Holotype

MTQ-G65423. Black Rock , off South Solitary Island, NSW, Australia (30°12′0.55″S, 153°15′27.05″E).

Other material studied

MTQ samples: G65424 (Paratype) same as holotype. G65425 Smoky Cape , NSW, Australia (30°54′22″S 15°35′9″E) . G65900 Bryon Bay , NSW, Australia . G666153 Bryon Bay , NSW, Australia .

Corallum

Pocillopora aliciae is characterized by its robust, almost horizontal branching. Small sub-branches arise vertically from the main branches, but are generally short, giving the colony an overall flat appear-

ance. Colonies seldom exceed 30 cm in diameter.

Branch endings are rounded and verrucae reduced to entirely absent.

Corallites and coenosteum

Calices are 0.8–1.1 mm in diameter, the columella is weakly developed and flat, ornamented with short spinulae. The septa are hexamerally arranged in two cycles and weakly developed, often only indicated by spinulae. The coenosteum is ornamented with short spinulae.

Colour and pigmentation of the live colony

Green.

Habitat and biology

The species was observed on rocky habitats at depths of 2– 32 m. Pocillopora aliciae releases brooded larvae after full moon ( Schmidt-Roach et al., 2012a). Although it has not been observed to spawn, it is expected to have a mixed mode of reproduction as observed in its sister taxon P. damicornis ( Schmidt-Roach et al., 2012b) .

Remarks

See Schmidt-Roach et al. (2013) for a more detailed description.

Distribution

The species has only been recorded on the east coast of New South Wales, Australia, from Byron Bay to Port Stephens. Genetic samples analysed originated from the Solitary Islands.

Figures

Figure 3. A, DAPC of gross morphological characters. Bi-plot indication of character (see Table 1 for explanation of characters) contribution is shown in blue. Individuals are represented by dots and groups by elipses. Box, cluster-based reassignment probabilities (dotted lines indicate probabilities if Type α is excluded from calculations). B, branch-based reassignment probabilities for each cluster; bars indicate genetic lineages [probability of reassignment of a branch (N = 133) (horizontal bars, y-axis) to a certain cluster (genetic lineage) (vertical bars, x-axis) is indicated by shades: white = 0, dark grey = 1]. Clusters: α, Pocillopora damicornis; β, P. acuta; e, P. eydouxi; m, P. meandrina; δ, P. aliciae; γ, P. verrucosa; x, P. bairdi sp. nov.

Figure 4. Fine-scale skeletal differences between genetic lineages. Left: phylogeny based on ORF region resolving in four main clades (bootstrap values over 70 are shown as grey numbers). Right: scanning electron micrographs of different species (bar on the left indicates scale). Clade 1: Pocillopora damicornis Type α (P. damicornis), P. damicornis Type β (P. acuta), P. damicornis Type δ (P. aliciae); Clade 2: P. damicornis Type γ (P. verrucosa), Pocillopora Type x, P. bairdi sp. nov.; Clade 3: P. eydouxi e, P. meandrina m; Clade 4: P. damicornis Type ε (P. cf. brevicornis) (no micrograph available).

Figure 5. A, haplotype network based on ORF DNA sequence data and incorporating published Pocillopora sequence data from other locations across the Indian and Pacific Oceans (total alignment length 594 bp). B, geographical account of these lineages on a global scale based solely on genetic lineages.

Figure 8. Pocillopora acuta. A, in situ appearance. B, skeleton of specimen. C and D, scanning electron micrographs of specimen (photos: Paul Muir). E, side view of corallum of holotype of Pocillopora acuta Lamarck, 1816 (photo: Michel Pichon). F, drawing by Esper (1791). G, P. acuta morph in situ. H, holotype of Pocillopora apiculata Ehrenberg, 1834. I, skeleton of compact morphology of P. acuta (MTQ-G66112).

Figure 9. Pocillopora aliciae. A, field appearance. B, skeleton of branch. C and D, scanning electron micrographs of corallite structure. E, corallum of holotype (MTQ-G65423) (Schmidt-Roach et al., 2013). F, typical growth from on reef slope.