Varicose Wart Slug

Reasoning recorded at review

• •Broad adult-like animal with several substantial longitudinal blue-grey tuberculate ridges
• •Broad black longitudinal bands and shorter lateral black branches separate the ridges
• •Many large ridge tubercles have yellow-orange caps
• •Both visible lamellate rhinophores are yellow-orange
• •The complete dorsal combination fits the variable adult Phyllidia varicosa series in Papu et al. (2022)

Alternatives considered

• Phyllidia haegeli

  Why plausible: P. haegeli is a documented varicosa mimic with longitudinal black lines, blue-grey ridges and yellow-capped tubercles.

  Comparison: The photographed angle does not establish whether the anus is dorsal or ventral, which is the key external separator in the modern revision.

• Phyllidia alyta

  Why plausible: P. alyta shares a black-line and orange-tubercle pattern.

  Comparison: The strong broad ridges, irregular branching bands and Papua New Guinea locality are not the western Indian Ocean P. alyta pattern described by Yonow; ventral and expert evidence would be required.

Reasoning recorded at review

• •Large adult-like animal with tall, continuous longitudinal blue-grey tuberculate ridges
• •Several broad black longitudinal bands run between the ridges and branch toward the margin
• •Prominent ridge tubercles have yellow-orange caps
• •The visible lamellate rhinophore is yellow-orange
• •The high ridges and elongate side profile closely match adult Phyllidia varicosa in Papu et al. (2022)

Alternatives considered

• Phyllidia haegeli

  Why plausible: The modern revision warns that P. haegeli can be mistaken for P. varicosa from dorsal photographs and shares this colour-and-ridge combination.

  Comparison: The frame contains dark dorsal markings but no opening can be identified confidently as the anus; a clear dorsal or ventral anal view is required.

• Phyllidia alyta

  Why plausible: P. alyta shares black dorsal lines and orange tubercles.

  Comparison: Its western Indian Ocean account describes a more linear four-line pattern and smaller, less-developed ridges; a ventral sole view and expert assessment would be needed to support it here.

Reasoning recorded at review

• •Elongate adult-like body with multiple substantial longitudinal blue-grey tuberculate ridges
• •Broad black longitudinal bands and shorter branching black marks separate the ridges
• •Numerous ridge tubercles have yellow-orange caps
• •The visible lamellate rhinophore is yellow-orange
• •The combined dorsal form falls within the varied Phyllidia varicosa series illustrated by Papu et al. (2022)

Alternatives considered

• Phyllidia haegeli

  Why plausible: Papu et al. show that P. haegeli can closely mimic P. varicosa dorsally, including black longitudinal lines, blue-grey ridges and yellow-capped tubercles.

  Comparison: A clearly documented dorsal versus ventral anal opening is needed; this frame does not expose the anal position unambiguously.

• Phyllidia alyta

  Why plausible: P. alyta also combines longitudinal black lines with linearly arranged orange tubercles and a dark sole line.

  Comparison: The photographed animal has more developed broad ridges and branching black fields, and P. alyta is reported principally from the western Indian Ocean; a ventral view and expert comparison would be needed to revive this alternative.