Tetralia brunalineata, 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 : 9-12

Tetralia brunalineata , new species

(Pl. 1, Fig. C; Pl. 4, Figs. A-G; Pl. 6, Fig. C; Pl. 7, Fig. C; Pl. 8, Fig. C)

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

Type material: Holotype, LACM CR 2002-040.3 (1 male) Mariana Is., Guam, Ipan Beach Park (13°27’N, 144°46'E), collected by snorkeling on reef crest (located approximately 30 m from shore) from Acropora sp., depth 2 m, Sept. 18, 2002, S. Trautwein coll. Paratypes (total of 10 specimens), Guam, Ipan Beach Park: LACM CR 2002-040.4 (allotype, 1 ovigerous female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.1 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.2 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.); Guam, Pago Bay (13°28’N, 144°46'E): LACM CR 2002-039.1 (1 male, 1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.2 (1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.3 (1 male, 1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.).

Other material examined (total of 52 specimens): Guam. Hagatna (= Agana) Bay (13°29’N, 144°45'E): LACM CR 2002-041.1 (1 male, depth 2 m, Sept. 16, 2002, S. Trautwein coll.), LACM CR 2002-041.2 (1 ovig. female, depth 2 m, Sept. 16, 2002, S. Trautwein coll.), LACM CR 2002-041.3 (1 male, 1 ovig. female, depth 2 m, Sept. 16, 2002, S. Trautwein coll.), LACM CR 2002-041.4 (1 male, 1 ovig. female, depth 2 m, Sept. 16, 2002, S. Trautwein coll.), LACM CR 2002-041.5 (1 male, 1 ovig. female, depth 2 m, Sept. 16, 2002, S. Trautwein coll.), LACM CR 2002-041.6 (2 females, depth 2 m, Sept. 16, 2002, S. Trautwein coll.); Pago Bay: LACM CR 2002-039.4 (1 male, damaged, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.5 (1 male, 1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.6 (1 male, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.7 (1 male, 1 ovig. female, 2 juveniles, all damaged, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.8 (1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.9 (1 male, 1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-039.10 (1 male, 1 ovig. female, depth 2 m, Sept. 17, 2002, S. Trautwein coll.), LACM CR 2002-040.5 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.6 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.7 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), SMF 26930 (1 male, 1 ovig. female, 1 female all labeled as Tetralia vanninii , depth 2 m, Sept. 15, 1997, P. Castro & E. Santiago coll.), SMF 26928 (1 male labeled as Tetralia vanninii , depth unknown, July 1997, P. Castro coll.); Ipan Beach Park: LACM CR 2002-040.8 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.9 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.10 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.11 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.), LACM CR 2002-040.12 (1 male, 1 ovig. female, depth 2 m, Sept. 18, 2002, S. Trautwein coll.).

Japan. Okinawa (26°16’N, 127°43'E): LACM CR 2004-018.1 (1 male, 1 ovig. female, depth 2 m, June 29, 2004, S. Trautwein coll.).

French Polynesia. Society Is., Moorea (17°32'S, 149°47'W): LACM CR 2001-052.1 (1 ovig. female, depth 3 m, July 24, 2001, S. Trautwein coll.), LACM CR 2006 -003.1 (1 male, 1 ovig. female, depth 1 m, April 28, 2006, S. Trautwein coll.), LACM CR 2006 -003.2 (1 ovig female, depth 1 m, April 28, 2006, S. Trautwein coll.), LACM CR 2006 -003.3 (1 male, 1 ovig. female, depth 1 m, April 28, 2006, S. Trautwein coll.).

Description. Carapace: Carapace quadrilateral to oval (Plate 4A), flattened in both sexes; carapace width exceeds length ( Table 1 ); anterolateral margins convex, particularly in females; exterior orbital angle blunt in adults (may be pointed in juveniles); frontal margin very finely denticulate with teeth more pronounced (dentate), more widely spaced laterally, notch absent (Plate 6C), setae few or absent between teeth.

Chelipeds: Chelipeds slightly unequal in females (major cheliped propodus only slightly higher than minor); cheliped size markedly dissimilar in males (major cheliped propodus being much higher than minor) (Plate 4A). Tomentose pit of major cheliped approximately 1/3–1/2 length of propodus in females (Plate 4E), greatly reduced in males, barely extending beyond proximal margin of propodus; several long setae distributed throughout tomentose pit in females, absent in males. Finger inner margins smooth, gaping in males (Plate 4F), dentate, non-gaping (touching) in females; dactylus length approximately 1/2 propodus length ( Table 1 ). Propodus granular; proximal dorsal surface with prominent red propodal knob (Plate 4G). Carpus anterior margin smooth, possibly bearing 1–2 teeth in both sexes (Plate 4D). Merus anterior margin denticulate to dentate without crest, but smooth laterally (Plate 4D); dorsal surface granular.

Fifth pereopod (P5): Few setae present on ventral surfaces of P5 propodus, dactylus. P5 dactylus dorsal surface with 3–4 large, strongly curved spines near tip (Plate 7C); ventral surface with 4–6 discontinuous transverse rows of flattened chitinous spinules with 3–4 spinules at ventral base of horny tip (Plate 8C). Distal, ventral margin of P5 propodus lined with several long chitinous spinules.

PLATE 4. Tetralia brunalineata , new species (LACM CR 2006 -003.1 freshly-collected male for images A, B, C, G; LACM CR 2002-040.3, holotype, preserved male for images D, F; LACM CR 2002-040.4, allotype, preserved female for image E). A. whole body, dorsal view; B. frontal margin, dorsal view; C. first and second left pereopods, note brown and white stripes; D. carpus of major right cheliped, arrows indicate carpus and merus anterior margin detail; E. female tomentose pit (arrow) of major left cheliped; F. median view of major right cheliped propodus and dactylus, arrow indicates gaping fingers; G. major left cheliped, dorsal/median view, arrow indicates bright red knob. All scale bars 1mm.

Male pleopods: Male first pleopods curved, distal 1/4 covered with sparse setae.

Live coloration: Anterior dorsal half of carapace and anterior portion of eyestalks dark brown, posterior half white (Plate 4A); frontal, orbital, anterolateral margins orange-brown; thin light blue line posterior to frontal margin extends across eyestalks (Plate 4B), appearing dark blue in preserved specimens. Ventral anterior region darker than posterior; buccal region’s color matches surrounding area; light blue line present on posterior epistome margin extending across eyestalks.

Cheliped fingers orange-red, may be white proximally (Plates 4F, 4G); dorsal surfaces of propodus, carpus dark brown becoming white ventrally (Plates 4E, 4F, 4G); anterior margins of propodus, carpus, merus, basi-ischium orange-red with merus anterior margin darker red than other margins (Plates 4C, 4D); anterior coxal margin color matches surrounding area. Propodal knobs dark red (Plate 4G).

Pereopods with alternating lines of dark brown and white extending along length of each podomere, most notably on dorsal and lateral surfaces of carpus, propodus, dactylus (Plate 4C); distal margins of merus, carpus, propodus orange-red (Plate 4C); large black spot absent at dorsal propodal-dactylar articulation on all pereopods.

Remarks. T. brunalineata differs from the other described species of Tetralia in its overall color pattern, primarily by the presence of brown stripes on the pereopods (Plate 4C) and bright red propodal knobs on the chelipeds (Plate 4G). In addition to the unique color pattern, T. brunalineata can be distinguished from other species of Tetralia by the following combination of morphological characters: (1) carapace width much greater than length, especially in females ( Table 1 ), (2) major cheliped fingers gaping in males (Plate 4F; see also T. aurantistellata ), (3) crest of cheliped merus absent (Plate 4D), and (4) tomentose pit of major cheliped greatly reduced in males. Males consistently show gaping fingers and the fingers’ inner margins never touch as in most tetraliid species. Gaping cheliped fingers, however, have been noted in males of other tetraliid species. Some museum specimens (SMF 26930) collected and color patterns described (and photographed) by Castro (2003) as T. vanninii are the new species T. brunalineata . This new species may be mistaken for T. nigrolineata due to the presence of a thin light blue line just posterior to a dark band on the carapace frontal margin of both species. However, the frontal margin of T. brunalineata is orange-brown, not black (or dark brown) as in T. nigrolineata . In addition, this frontal margin coloration is present on the anterolateral margins in T. nigrolineata , but absent on the anterolateral margins in T. brunalineata .

Distribution. Tetralia brunalineata has so far been identified from Okinawa, Guam, and Moorea, French Polynesia.

Etymology. From “brunneus” (Medieval Latin) for brown, “linea” (Latin) for line in reference to the brown lines on the pereopods.