Corresponding author: Yara Tibiriçá (
Academic editor: Matthias Glaubrecht
The nudibranch diversity of the western Indian Ocean is comparatively one of the least studied in the world. In this paper a sponge-like
The systematic of the genus
Despite current research efforts to raise the biodiversity knowledge of nudibranchs from the western Indian Ocean (e.g.
Six specimens were collected by scuba diving in Ponta do Ouro (
Specimens were dissected by dorsal incision under a dissecting microscope Nikon SMZ18. Their reproductive system was separated, examined and drawn under a dissecting microscope Leica 80 with an attached camera lucida. Surrounding radula tissue was removed by immersing in 10% sodium hydroxide for about 8 hours or on a solution containing 180 mL of the tissue lysis buffer ATL with 20 mL of proteinase K-solution incubated in 56 °C for 48h (
DNA extraction and amplification were conducted by the peripheric services of the Instituto Universitario de Investigacion Marina (INMAR–UCA). Genomic DNA was extracted from a small sample of foot tissue using the Qiagen DNeasy Blood & Tissue extraction kit, following the manufacturer’s instructions. One mitochondrial gene cytochrome c oxidase subunit (
All sequences were revised and examined in Geneious v.10.2.4 (
Maximum likelihood (
Three molecular species delimitation analyses were conducted to aid the species hypothesis. Firstly, Species by Automatic Partitioning (ASAP) was performed on the in-group
Ponta do Ouro, Mozambique (
Specimens were collected on submerged subtropical compressed sandstone reefs in Ponta do Ouro, Mozambique.
Body elongate-ovulated. Dorsum pale gray to pink, covered on highly dense caryphyllidia; rhinophores short, with up to nine lamellae, ending in a knob apex; six to nine bipinnate branchial leaves encircling the anal pore. Radula with five to seven very thin pectinated outermost teeth bearing long bundled fibrous denticles. Labial cuticle smooth. Copulatory spine with bifid apex.
This species is dedicated to Livia Renée Cornelius, daughter of the second author of this paper.
Microcomputed tomography (µCT) of
Smooth labial cuticle (Fig.
Radular formula difficult to determinate as outermost teeth are very thin and overlapping each other (Fig.
Oesophagus passing through nerve ring, where it folds. Pair of salivary glands, relatively short, uniform, near the base of oesophagus (4A). Oesophagus connects to oval stomach. Intestine about half of oesophagus diameter. Caecum locate ventrally to stomach. Digestive gland cone-shaped, occupying approximately 30% of visceral mass. Anus opening at the center of gill circle.
Central nervous system partially covered by blood gland. This is divided into two parts, anterior part about half the size of posterior part. Cerebral ganglia about half the size of pleural ganglia. Cerebral ganglia and pleural ganglia fused. Pedal ganglia ventrally located connected by a simple pedal commissure. Buccal ganglia short, ventrally located. Rhinophoral ganglia bulb-shaped, about 30% the size of cerebral ganglia. Eyes connected to cerebral gland by short rhinophoral nerve (Fig.
Hermaphroditic duct leading to an ampulla long and convoluted, located between female gland and accessory gland. Ampulla branching into short oviduct and prostate. Flattened and ovulated prostate narrowing into a thin deferent duct, expanding into ejaculatory portion. Penis unarmed. Accessory gland size and shape varied according to the specimen, from pear-shaped and similar size to the female gland MNCN15.05/200187 to elongated and half of the size MNCN15.05/200189; in all specimens it narrows into a very thin, highly convoluted tube. Copulatory spine in accessory gland of approximately 1.25 mm (Fig.
This species has only been seen associated with the sponge
We successfully amplified the gene
Bayesian inference tree based on the concatenate sequence dataset (
The family
The
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Intra-specific | ||||
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0–0.15% | |||||
10.30 | 0.15–0.68% | |||||
9.08 | 3.65 | 0.15–0.92% | ||||
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14.29 | 14.74 | 13.06 | 0.16–1.08% | ||
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12.61 | 10.74 | 10.45 | 12.31 | N/A | |
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16.92 | 17.78 | 17.78 | 16.92 | 16.92 | 0.46–14.18% |
The phylogenetic relationships within the family
Comparative morphology of valid
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Geographic range | Indo-Pacific inc. western Indian Ocean | Australia and New Zealand | Indo-Pacific inc. western Indian Ocean | Indo-Pacific inc. western Indian Ocean | Southern Australia | Western and Central Pacific | Indo-Pacific inc. western Indian Ocean | Red Sea & western Indian Ocean | Mozambique |
Dorsal color | White to yellow-cream, dark brown rings of different sizes | Purplish brown to pale brown with dark patches | Cream-grey to yellow with oval yellow spots, rings, horizontal black stripes | Dark orange to dark brown, caryophyllidia dark brown | Pale pink, large brown patches encircled with white or dark purple spots | Pale grey, dark grey spots, line of dark spots from rhinophores to gill | Pale grey to light brown with patches of similar color | White to dark dull grey with light brown spots | Pinkish grey, darker spots sometimes present |
Rhinophores | 14–20 lamellae | 16 lamellae, terminal knob | 23–25 lamellae | 13–15 lamellae | 7–8 lamellae | ≈ 10 lamellae | short, up to 13 lamellae, terminal knob | wide, 8–11 lamellae | short, 6–8 lamellae, terminal knob |
Rhinophore color | White with black apexes | Base colorless, uppermost lamellae speckled in white | Base black or cream-yellow, club black-spotted with white or cream-colored spots | Base light yellow with dark clubs, or dark brown rachises with light yellow clubs | White | Cream-brown with pale grey-brown club | Pale-grey, speckled with dark brown, white on the club | Same than mantle | White to pinkish |
Branchial leaves | 6 tripinnate | up to 11, bi-tripinnate | 6–7, tripinnate | 7, bipinnate | 10, bipinnate | 12, tripinnate | 10, bipinnate | 11, bipinnate | 6–9, bipinnate |
Gill color | White with dark black delineations | Same than mantle | Base white, dark brown rachises | Light yellow, base dark brown, tips light-yellow, dark brown rachises | White | Grey to brown with cream glandular spots | Dark grey | ? | White to pinkish |
Foot sole color | Dark spots around the margin, sole translucent white | Margins sparsely speckled, sole translucent white | Black stripes on sole and laterals, sole white or cream | Dark spots around margin, brown line dorsally, translucent yellow sole | Pink | Pale gray | ? | ? | Whitish-pink |
Upper lip color | White to yellow cream | ? | Cream yellow, speckled with black | Yellowish, sometimes with two brown spots on each side of the lip | ? | Cream in preserved animals | ? | ? | White |
Oral tentacles color | White to cream, with brown spots in some specimens | Speckled | Light white to yellow | Yellowish | White | Pale gray | ? | ? | White-pinkish |
Caryophyllidia size | ≈ 220µm | ? | ≈ 176µm | ≈ 250µm | ? | ≈ 133µm | ≈ 220µm | ≈ 190µm | ≈ 140µm |
Mantle Glands | White, distributed around the mantle edge | ? | ? | White, large, distributed around the mantle edge | ? | Absent | White, distributed around the mantle edge | ? | Absent |
Foot | Dorsally visible when the animal is in motion | Dorsally visible when the animal is in motion | Dorsally visible when the animal is in motion | Dorsally visible when the animal is in motion | ? | Dorsally visible when the animal is in motion | No prolongation present | ? | Rarely visible dorsally |
Radula | 21 × (21.0.21) in 20mm-long preserved specimen | 20 × (28.0.28) no more information | 26 × (18.0.18) in 18mm specimen | 20 × (15.0.15) in 6mm-long preserved specimen | 21 × (23.0.23) in 18mm-long preserved specimen | 16 × (17.0.17) in 20mm-long preserved specimen | 14 × (18.0.18) in 5mm-long preserved specimen | 19 × (17.0.17) in 10mm preserved specimen | 38 × (6–7.26.0.26.6–7) in 20mm specimen |
Innermost teeth | Hamate, shorter and thinner than midlateral teeth, lacking denticles | Hamate, small, lacking denticles | Hamate, blunt, lacking denticles | Hamate, elongated, lacking denticles | Hamate, lacking denticles | Hamate, pointed, shorter than the midlateral teeth, lacking denticles | Hamate, elongate, with up to 3 denticles near the cusp | hamate, single cusp close to base | Hamate, lacking denticles |
Midlateral teeth | Hamate, lacking denticles | Hamate, lacking denticles | Elongated, blunt, lacking denticles | Hamate, lacking denticles | Hamate, lacking denticles | Hamate, pointed, lacking denticles | Hamate, pointed, lacking denticles | Hamate, lacking denticles | Hamate, lacking denticles |
Outermost teeth | Hamate, lacking denticles | Hamate, lacking denticles | Shorther than midlateral teeth, curved pointed, lacking denticles | Smaller than midlateral teeth. The 5 outermost have up to 5 denticles | Elongated, lacking denticles | Small, elongated, smooth or sometimes with a single denticle near the cusp | elongated, first three outermost teeth with up to 3 denticles | shorter, hamate, pointed | pectinate, 5–8 long fibrous denticles |
Labial cuticule | Smooth | With jaw elements | Smooth | Smooth | With jaw elements | With jaw elements | With jaw elements | With jaw elements | Smooth |
Accessory gland and spine | Present, curved spine ≈ 717µm long | Present, long pointed spine | Present, curved spine ≈ 3.7mm long | Present, spine ≈ 477µm long | Present, spine ≈ 198µm long | Present, curved spine ≈ 1.03mm long | Present, curved spine ≈ 2.25mm long | Present, curved spine ≈ 600µm long | Present, curved spine ≈ 1.25mm long |
The Indo-Pacific species that most resembles
Based on morphological and genetic data there is no doubt that
We are grateful to Miguel Gonçales (Park Warden) for assisting with the collection permit. We thank Daniela de Abreu and Alvaro A. Vetina for helping with the depositing of specimens at Museu de História Natural de Maputo (
List of specimens used in the molecular analysis with respective sample localities, voucher number and GenBank accession numbers.
Species | Locality | Voucher |
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Norway: Frøya | NTNU-VM-58891 |
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Norway: North Sea | ZMBN 125946 |
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Norway: Kristiansund | ZMBN 127749 |
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Guam: Mariana Islands | CPIC00633 |
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Sister Islands: Singapore | IP0011 |
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Sister Islands: Singapore | IP0302 |
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Norway: Gulen | ZMBN 127710 |
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Northern Ireland: Ballyhenry Is. Northern | ZMBN 127711 | |
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France: La Rochelle | ZMBN 125512 | |
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Norway: Frøya | NTNU-VM-58888 | |
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Northern Ireland: Ballyhenry Island | ZMBN 127709 | |
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Spain: Pontevedra, Galicia | ZMBN 132446 | |
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Spain: Huelva | ZMBN 125474 |
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Mozambique: Ponta do Ouro | MNCN15.05/200189 |
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Mozambique: Ponta do Ouro | MNCN15.05/200187 |
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Mozambique: Ponta do Ouro | MNCN15.05/200188 |
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Mozambique: Ponta do Ouro | MNCN15.05/94693 |
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Bayesian maximum credibility tree of the
phylogenetic
Bayesian maximum credibility tree of the
Table of locality
occurences
Table of locality of collected specimens of