Typton tortugae McClendon, 1911

Fransen, Charles H. J. M., 2023, The marine palaemonid shrimps (Crustacea, Deapoda, Caridea) of the Dutch Caribbean, Zootaxa 5387 (1), pp. 1-127 : 113

Typton tortugae McClendon, 1911

( Figs. 73–74 )

Typton tortugae — Westinga & Hoetjes 1981: 142, tab. 2 ( Curaçao).

Material examined. Curaçao: ZMA. CRUS.D.103215: 1 male, pocl. 2.6 mm; 1 female pocl. 2.6 mm: St. Michiel , 11.xii.1975, depth 3 m, in Spheciospongia vesparia , collected by P. Hoetjes S-110876-I . ZMA. CRUS.D.103216: 1 male, pocl. 3.0 mm, St. Michiel , 21.i.1975, depth 3 m, in S. vesparia , collected by P. Hoetjes S-210175-I . ZMA. CRUS.D.103217: 1 fov. pocl. 2.7 mm; 1 male, pocl. 3.0 mm: St. Michiel , 4.ii.1976, depth 3 m, in S. vesparia , collected by P. Hoetjes S-040276-I . ZMA. CRUS.D.103218: 1 ovigerous female., pocl. 3.7 mm, 1 male, pocl. 3.1 mm, St. Michiel , 12.viii.1976, depth 3 m, in S. vesparia , collected by P. Hoetjes S-120876-I . ZMA. CRUS.D.103219: 1 female, pocl. 3.1 mm, St. Michiel , 19.x.1976, depth 3 m, in S. vesparia , collected by P. Hoetjes S-181076-I (with damaged axiid) .

Remarks. The present specimens correspond closely to the description by McClendon (1911) and the redescription by Anker et al. (2021). The specimens have the rostrum compressed, slightly upturned distally, short, not reaching midlength of the eyestalk ( Fig. 73A, B ); paraorbital process in form of well-developed triangular lobe; pterygostomial margin slightly produced anteriorly, rounded. Eyes reaching distal margin of basal antennular segment; cornea sperical, oblique, without Nebenauge; eyestaks laterally compressed, with distinct longitudinal dorsal carina ( Fig. 73B ). Sixth somite of pleon without median posterior tooth, with posterolateral angle produced into subacute tooth ( Fig. 73C ). Telson ( Fig. 73C ) with two pairs of dorsal spines; anterior pair submarginal at 0.22 of telson length, posterior pair marginal at 0.63 of telson length; lateral pair of terminal spines ( Fig. 73D ) small, less than half length of dorsal spines; intermediate and median spines equal in length; distal margin of telson straight. Antennular peduncle ( Fig. 73A, B ) with basal segment without distolateral tooth; stylocerite short, not reaching midlength of basal segment; intermediate and ultimate segments short, as long as broad; upper outer flagellum with 3–5 segments fused, shorter free ramus unisegmented, longer ramus short, with about 5–6 segments; lower inner flagellum about as long as longer free ramus of upper outer flagellum. Antenna ( Fig. 73A, B ) with peduncle very slender, unarmed, carpocerite reaching midlength of intermediate segment of antennular peduncle. Second pereiopods ( Fig. 74A ) subequal in size and form in present material, in the type material there seems to be a slightly bigger difference in size ( McClendon 1911: Plate 1 fig. 2); ventral margins of merus, carpus, palm and fixed finger with acute short tubercles whereas in the type-series the ischium also shows a few tubercles ventrally ( Anker et al. 2021: fig. 4A); dactylus subcircular, extending beyond fixed finger. Third pereiopod ( Fig. 74B ) more robust than fourth ( Fig. 74D ) and fifth ( Fig. 74F ); propodus with one ventral spine in proximal part of flexor margin, one ventral spine in distal part of flexor margin, and a pair of spines distoventrally; propodus of fourth pereiopod with one subdistal ventral spine and a pair of ventrodistal spines; fifth pereiopod without ventral nor ventrodistal spines, with distoventral part of propodus with rows of serrate setae; dactyli of ambulatory pereiopods ( Fig. 74C, E, G ) biunguiculate; accessory tooth small, subdistal; unguis distally hooked, with few rows of scales on proximodorsal margin. Uropods ( Fig. 73C ) not exceeding telson; exopod with entire, convex lateral margin ending in distinct acute distolateral tooth, flanked by mobile inward curved spine, twice as long as distolateral tooth ( Fig. 73E ).

Ecology. Endosymbiont of sponges. Recorded from Spheciospongia vesparia ( Pearse 1932; Westinga & Hoetjes 1981), and Ircinia strobilina (Duchassaing De Fonbressin & Michelotti, 1864) ( McClendon 1911, as Hircinia acuta (Duchassaing & Michelotti, 1864)) ; Santana-Moreno et al. 2013).

Distribution. Known from the Western Atlantic: Bermuda, the Dry Tortugas, Virgin Islands, Gulf of México (Yucatan peninsula), Brazil (Pará, Maranhão and Fernando de Noronha), in depths to 45m ( Chace 1972; Vieira et al. 2012; Santana-Moreno et al. 2013). The specimen recorded from the Gulf of California in the East Pacific ( Holthuis, 1951b; Wicksten 1983) has recently been recognised as a distinct species: Typton cousteaui Anker, Pachelle & Leray, 2021 .

Figures

FIGURE 73. Typton tortugae McClendon, 1911, ZMA.CRUS.D.103215, ovigerous female, pocl. 2.5 mm. A, anterior appendages, lateral view; B, idem, dorsal view; C, tailfan; D, telson, distal margin; E, left exopod uropod. Scale bars: A–C=1.0 mm; D, E=0.125 mm.

FIGURE 74. Typton tortugae McClendon, 1911, ZMA.CRUS.D.103215, ovigerous female, pocl. 2.5 mm.A, right major second pereiopod, lateral view; B, left third pereiopod, mesial view; C, idem, dactylus and distal part propodus; D, left fourth pereiopod, mesial view; E, idem, dactylus and distal part propodus; F, left fifth pereiopod; G, idem, dactylus and distal part propodus. Scale bars: A=2.0 mm; B, D, F=1.25 mm; C, E, G=0.125 mm.