Tetralia brengelae, Trautwein, Sandra E., 2007

Trautwein, Sandra E., 2007, Four new species of coral crabs belonging to the genus Te tra li a Dana, 1851 (Crustacea, Decapoda, Brachyura, Tetraliidae), Zootaxa 1450, pp. 1-20 : 7-9

Tetralia brengelae , new species

(Pl. 3, Figs. A-G; Pl. 6, Fig. B; Pl. 7, Fig. B; Pl. 8, Fig. B)

Tetralia vanninii – Castro, 2003:442 (part).

Type material: Holotype, LACM CR 2002-040.23 (1 male) Mariana Is., Guam, Pago Bay (13°28’N, 144°46'E), collected by snorkeling on reef crest from Acropora sp., depth 2 m, Sept. 18, 2002, S. Trautwein coll. Paratypes (total of 2 specimens), Guam, Pago Bay: LACM CR 2002-040.23 (allotype, 1 ovigerous female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-039.11 (1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.).

Other material examined (total of 10 specimens): Guam. Pago Bay: LACM CR 2002-039.11 (1 male, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.12 (1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-040.23 (1 juvenile, depth 2 m, Sept. 18, 2002 S. Trautwein coll.), SMF 26929 (2 ovig. female, 1 female all labeled as Tetralia vanninii , depth 2–4 m, Sept. 10, 1997); Ipan Beach Park (13°27’N, 144°46'E): LACM CR 2002-040.24 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002 S. Trautwein coll.); Haputo (13°57’N, 144°82'E): UF 911 (1 male and 1 ovig. female labeled as Tetralia vanninii , depth 2.8 m, August 7, 2001, G. Pauley coll.).

Description. Carapace: Carapace quadrilateral, flattened in males and oval, flattened in females (Plates 3A, 3B); carapace width exceeds length ( Table 1 ); anterolateral margins parallel in males, slightly convex to convex in females; exterior orbital angle pointed in males, blunt in females; frontal margin finely denticulate with teeth more pronounced, more widely spaced laterally, granulations on inner orbital margins, notch absent (Plate 6B), setae few to absent between teeth.

Chelipeds: Cheliped size unequal in both sexes (Plate 3A). Tomentose pit approximately 1/3–1/2 propodus length in females (Plate 3E), 1/4 propodus length in males; several long setae throughout tomentose pit in females, absent in males. Finger inner margins dentate, non-gaping (touching) in both sexes (Plate 3F); dactylus length less than 1/2 propodus length, causing fingers to appear short (Plate 3G, Table 1 ). Propodus strongly granular; proximal, dorsal surface with prominent brown propodal knob with white tip (Plate 3D). Carpus anterior margin slightly serrated bearing a series of small teeth with medial teeth more prominent than lateral teeth, margin may appear smooth with only one or more granules (Plate 3D). Merus anterior margin dentate without crest (Plate 3D); dorsal surface granular.

PLATE 3. Tetralia brengelae , new species (LACM CR 2002-039.11 freshly-collected female for image A; LACM CR 2002-040.23 allotype, preserved female for images B, E, G; LACM CR 2002-040.23 holotype, preserved male for images C, D, F). A. whole body, dorsal view; B. frontal margin and anterior carapace region, dorsal view, arrows indicate blue lines; C. left 2nd and 3rd pereopods, dorsal/posterior view; D. major right cheliped, dorsal view, arrows indicate carpus and merus anterior margins; E. female tomentose pit (arrow) of major right cheliped; F. major right cheliped propodus and dactylus, median view; G. major right cheliped propodus and dactylus, dorsal/median view, arrow indicates short fingers. All scale bars 1mm.

Fifth pereopod (P5): Few setae on ventral surfaces of P5 propodus, dactylus. P5 dactylus dorsal surface with 5 large, strongly curved spines near tip (Plate 7B); ventral surface with 4 discontinuous transverse rows of flattened chitinous spinules ending in 2–3 chitinous spinules at ventral base of horny tip (Plate 8B). Propodus distal, ventral margin lined with several long chitinous spinules.

Male pleopods: Male first pleopods straight, distal 1/3–1/2 covered with setae.

Live coloration: Anterior dorsal half of carapace yellow or brown (including anterior portion of eyestalks), posterior half white (Plates 3A, 3B); frontal region composed of three successive lines extending laterally to anterior portion of eyestalks and exterior orbital angle: most anterior margin brown followed by black line composed of dense spots (dark brown in preserved specimens) followed by thin light blue line, light blue line may or may not extend from the center of each orbit margin and run parallel to anterolateral margin for approximately 1/4–1/3 length of carapace (Plate 3B). Anterolateral margins dark brown (or matches color of anterior region of carapace). Ventral anterior region brown; buccal region white; dark line extending across posterior epistome margin.

Cheliped fingers red to orange in both sexes (Plates 3A, 3F, 3G); distal half of dorsal surface of propodus may be lighter than proximal half (Plate 3A) or uniformly brown (Plate 3G); dorsal surfaces of proximal propodus region, carpus, merus dark brown (Plate 3D) becoming white ventrally; anterior margins of merus, carpus dark brown, teeth white (Plate 3D); anterior margins of basi-ischium, coxa light brown. Propodal knob dark brown, usually with white tip (Plate 3D).

All podomeres of pereopods bear alternating bands of dark brown and red with red bands located at dorsal surface of podomere articulations (Plate 3A), white on ventral surfaces; large black spot absent at dorsal propodal-dactylar articulation on all pereopods.

Remarks. T. brengelae differs from the other described species of Tetralia in its color pattern, most especially by the presence of a thin, light blue line that originates from the center of each orbital margin and runs posteriorly and partially along the carapace (Plates 3A, 3B), although this character may be absent in some specimens. Some museum specimens (SMF 26929) identified by Castro (2003) as T. vanninii belong to the new species T. brengelae . Castro (2003: 442) described the same color pattern as “elongate blue spots extended from the edge of the orbits into the yellow band.” Other unique color features include alternating red and brown bands on the pereopods (with red articulations), and cheliped fingers that are bright red (Plate 3A). In addition to the unique color pattern, T. brengelae can be distinguished from the other described species of Tetralia by combination of the presence of uniform teeth along the frontal margin (Plate 6B) and by the length of dactylus of the major cheliped being less than 1/2 propodus length (Plate 3G, Table 1 ) making the fingers appear short. T. brengelae shares bright red, “short” major cheliped fingers and presence of a blue pattern near the anterolateral carapace border with T. cinctipes and may be mistaken as such. However, the blue color forms a thin line parallel to the anterolateral margins in T. brengelae , whereas the blue color is a broad band that extends to the anterolateral margins in T. cinctipes .

Distribution. Tetralia brengelae is so far known only from Guam.

Etymology. The species name is in honor of Ms. Lynn Brengel in recognition of her scientific contributions to the Natural History Museum of Los Angeles County.