132 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
Island, Philippines, 13°45T 8.997"N 120°54'24.19"E collected May 1, 2011 by Vanessa Knutson 
and Michele Weber, subsampled for DNA, preserved specimen 5.2 mm length with part of the 
“tail” missing. CASIZ 185963, one specimen, dissected, subsampled for DNA, CASIZ 185966, 
one spechnen dissected subsampled for DNA, preserved specimen 6.0 mm length with part of the 
“tail” missing, CASIZ 185975, one specimen, subsampled for DNA, preserved specimen 5.0 mm 
length with part of the “tail” missing, all collected on May 04, 2011 at the Anilao Harbor, Anilao, 
Balayan Bay, Batangas Province, Luzon Island, Philippines, 13°45'35.70''N 120°55G4.20"E by 
Michele Weber. 
There are a couple of photos on the Nudipixel website of this species {<http://www.nudipixel. 
net/photo/00034049/> and <http://www.nudipixel.net/photo/00034646/>). These photos were taken 
from Anilao within approximately one month of when the specimens described here were collect¬ 
ed. 
Geographical distribution. — Currently known only from Balayan Bay, in the Anilao 
region of the Philippines. 
Etymology.— Gymnodoris brunnea is named for its brownish coloration. 
External morphology.— Several preserved specimens were subsampled for DNA before 
being measured and ranged between 5.0 and 8.0 mm in length with a subsection of the posterior 
end of the “tail” missing. Two intact preserved specimens were about 9.5 mm in length. The living 
animals (Fig. 1 A, B) are translucent with a brownish tinge. Upon close inspection of the preserved 
specimens, this brownish hue appears to come from elongate dark particles present throughout the 
tissue of the animal. These dark particles appear to be generally concentrated on the dorsal side of 
the animal. The sides and dorsum of the body are covered in deep orange, conical pustules. These 
pustules are present on the anterior portion of the notal margin. Starting from the anterior margin, 
these pustules are situated in two rows following the mantle margin posteriorly and converge to a 
point roughly halfway between the gills and the tip of the posterior end of the foot. From here, the 
pustules continue in a row to the tip of the foot. Pustules can also be found between the 
rhinophores. In some of the preserved specimens, the very tip of the foot is keeled. 
The foot is broad, widest anteriorly beneath the rhinophores. The foot has a thick anterior mar¬ 
gin with a deep groove that separates the foot from the rest of the head. The anterior margin is 
tinged in deep orange. The rhinophores are perfoliate with approximately 8-9 lamellae and are 
tipped with orange. In some specimens, the orange runs down the anterior portion of the 
rhinophores, and wraps slightly around the sides, where it gi'adually fades. In some of the preserved 
specimens, the rhinophores were partially retracted and thus some lamellae were not visible. 
The genital opening is located on the right side of the body, just anterior to the gill plume. The 
gill branches are arranged in a linear row or slight arc with between 4-7 unipinnate filaments. The 
filaments are tinged with a deep orange color with deeper pigmentation apically, when present. 
This coloration varies between specmiens. In some specimens, the orange pigment is quite concen¬ 
trated and may cover much of the gills; in others, the orange pigment covers only the apical por¬ 
tion of the gills. One specimen had a negligible amount of orange on the gills. The length of the 
gill filaments also varies. 
Due to the translucent nature of the skin, the internal organs can be viewed externally. There 
is a wliite-colored patch visible just below the skin that extends forward and behind the gill, cov¬ 
ering a portion of the dorsal side of the digestive gland. The frmction of this white patch is 
unknown. The ovotestis appear to be a light orange in color and appear to be located in various 
parts of the animal, including a section towards the posterior tip of the foot, approximately halfway 
between the gills and tip of the foot. The intestine is also visible through the skin as a dark colored 
arch anterior to the gill. 
