Leucothoe bannwarthi ( Schellenberg, 1928 )

Kristine N. White & Traudl Krapp-Schickel, 2017, Red Sea Leucothoidae (Crustacea: Amphipoda) including new and re-described species, European Journal of Taxonomy 324, pp. 1-40 : 11-15

Leucothoe bannwarthi ( Schellenberg, 1928)

Figs 4–5

Leucothoella bannwarthi Schellenberg, 1928: 638 –640, fig. 199.

Leucothoella bannwarthi – Monod 1937: 13, fig. 8. — Barnard 1937: 153. — Schellenberg 1938: 26. — Ruffo 1969: 11–12. — Ledoyer 1967: 127, fig. 5A; 1972: 250; 1978: 300; 1979a: 107, fig. 68/1; 1986: 680, fig. 262.

non Leucothoella bannwarthi – Barnard 1965: 492, fig. 7. — Olerød 1970: 370. — Myers 1985: 4, figs 4–75. — Ortiz & Lalana 1997: 108.

non Leucothoella banwarthii [sic] – Myers 2013: 307.

Type material

Type material collected by Schellenberg and deposited at the Berlin Museum, MNHB-19936 (examined).

Type locality

Suez Channel, Red Sea.

Additional material examined

SUDAN: 19 specimens, Port Sudan, stn 160, Dec. 1970, U. Schiecke leg.; 19 specimens, Port Sudan, stn 168, Dec. 1970, U. Schiecke leg. (slide MVRCr 7726); 1 ♂, 3 mm, Port Sudan, stn 188, Dec. 1970, U. Schiecke leg. (slide MVRCr 7731); 54 specimens, same data as previous; 1 ♀ (ovigerous), 3 mm, near Port Sudan, Marsa Arakiyai, stn 195, 1–3 m, sponge, 12 Aug. 1970, U. Schiecke leg. (slide MVRCr 7725); 1 ♂, 3 mm, same data as previous (slide MVRCr 7728); 42 specimens, same data as previous.

Diagnosis (male)

Head anterior margin rounded. Coxa 1 trapezium-shaped, antero-distal corner acute, rounded in larger ones (due to abrasion?). Gnathopod 1 carpus curved; dactylus reaching 0.5 times propodus length. Gnathopod 2 carpus reaching 0.4 times propodus length; propodus palm scalloped. Pereopods 5–7 bases rectolinear, posterodistal corner lengthened but not widened. Telson distally acute.

Redescription

LENGTH. 3–3.3 mm.

HEAD. Anterior margin rounded, anterodistal margin evenly rounded, distal margin straight; eyes present with more than 10 ommatidia, round. Antenna 1 about half body length, flagellum 8-articulate, peduncle article 1 width less than 2 times article 2, accessory flagellum 1-articulate. Antenna 2 subequal in length with antenna 1, flagellum 8-articulate. Mandibular palp ratio of articles 1–3 1.0: 2.4: 1.5, article 2 with marginal setae, article 3 with distal setae. Maxilla 1 palp 2-articulate. Maxilla 2 inner and outer plates each with several short distal setae. Maxilliped inner plates distal margin rounded, with several small setae; outer plate inner margin smooth, reaching 0.1 times palp article 1, with marginal seta; palp article 4 length 1.3 times article 3 length.

PErEON. Coxae 1–4 relative widths 1.0:2.1: 1.6: 1.5. Gnathopod 1 coxa deeper than wide, smooth or weakly serrate, beset with many short setae on anterior and inferior margin, anterodistal margin pointed in young specimens, rounded in larger ones (due to abrasion?), distal margin straight, posterior margin excavate; basis slightly inflated, anterior and posterior margins with short setae; ischium bare; carpus curved, distal length 16 times width; propodus straight, palm smooth with small subdistal setae; dactylus smooth, reaching 0.5 times propodus length. Gnathopod 2 coxa wider than deep, smooth, beset with short setae, anterior margin concave, anterodistally acutely lengthened with long and thin tooth, distal margin straight, posterior margin not excavate; basis straight, anterior margin with six medium setae, posterior margin with 4 short setae; carpus 0.4 times propodus length, curved, distally tapering, densely setose, with strong distal spine; propodus with primary mediofacial setal row reaching 0.5 times propodus length, secondary mediofacial setal row parallel to anterior margin with three setae, scalloped; dactylus curved, reaching 0.6 times propodus length, smooth, bare, distally tapered. Pereopod 3 coxa rectangular, much wider than deep, smooth, anterior margin rounded, distal margin rounded, posterior margin not excavate. Pereopod 4 coxa anterior margin slightly protruding, anterodistal corner blunt, inferior margin straight. Pereopods 5–7 coxae shallow. Pereopods 5–7 bases width-length ratios 1: 2.9, 1: 2.5, 1:2.3, rectolinear, posterior margins smooth, bare, posterodistal corner rounded, lengthened, but not widened.

PLEON. Epimeron 1 bare, epimera 2–3 each with one seta, epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0:0.9: 1.1. Uropod 1 peduncle 1.2 times inner and outer rami lengths, rami subequal in length. Uropod 2 peduncle and outer ramus 0.8 times inner ramus length. Uropod 3 peduncle 1.7 times inner ramus length, outer ramus 0.8 times inner ramus length. All uropods beset with short spines. Telson 1.8 times longer than wide, apex acute.

Female (sexually dimorphic characters) Gnathopod 2 propodus palm smooth.

Remarks

In the original description of material from the Suez Channel, Schellenberg (1928) reports a male of 4 mm and a female of 3.6 mm. Coxa 1 is described as anteriorly and inferiorly serrate, clearly very acuminate and obviously broader than deep.

Ruffo (1969: 11–12) writes about five specimens from Museri, off Eritrea: “I compared these animals with Schellenberg 1928, Monod 1937 and J.L. Barnard 1965 and find large correspondence besides the coxa 1, which is much more rounded.”

Ledoyer (1979: fig. 68/1) shows the coxa 1 of a specimen from Madagascar with an acute anterior corner of about 60 degrees (no indication of length), while in 1986 (fig. 262) he describes other material from Madagascar, among which a male of 4 mm shows coxa 1 is similar to ours in the length to width ratio, but also definitely with an acute antero-distal corner, and slightly serrate.

In 1972, Ledoyer describes Leucothoe angusticoxa with an anteriorly pointed coxa 2 and a rounded coxa 1, where the gnathopods would also match quite well with the material here studied. However, pereopods 5–7 bases are in L. angusticoxa much wider and rounded, with telson longer in relation to width and not distally pointed, and uropod 3 rami longer in relation to the peduncle.

Our material is mainly with an anteriorly rounded coxa 1; only in station 188 did we find two smaller specimens with an acute corner. For the moment we assume that these two forms are probably not two different species, and ascribe both to L. bannwarthi .

From outside this region, J.L. Barnard (1965) illustrated material from Micronesia with a male of 2.5 mm where coxa 1 is deeper than wide, serrate anteriorly and inferiorly.

Myers (1985) also described much smaller specimens from Fiji (male of 2.1 mm), with the telson much shorter and rounded, uropod 3 outer ramus 2 times inner ramus length, and coxa 2 anterior margin serrate.

Thus we think that the material from the Red Sea and Madagascar may both deal with Schellenberg’s Leucothoe bannwarthi where coxa 1 anterodistal corner is acute but can be smoothed by abrasion, whereas the specimens from the South Pacific (Fiji and Micronesia) are a separate smaller species deserving another name (see L. alani sp. nov. above).

Ecology

This species was collected among sponges and coral rubble.

Distribution

Red Sea: Suez Canal ( Schellenberg 1928; Monod 1937; K.H. Barnard 1937); Museri Island off Eritrea ( Ruffo 1969); Port Sudan (present study).

Figures

Fig. 4. Leucothoe bannwarthi (Schellenberg, 1928), ♂, length 3.0 mm (MCRCr 7726); ♀, length 3.0 mm (MVRCr 7725).

Fig. 5. Leucothoe bannwarthi (Schellenberg, 1928), ♂, length 3.0 mm (MCRCr 7726); ♀, length 3.0 mm (MVRCr 7725).