Synalpheus hoetjesi, Hultgren & Macdonald Iii & Duffy, 2010

Hultgren, Kristin M., Macdonald Iii, Kenneth S. & Duffy, J. Emmett, 2010, Sponge-dwelling snapping shrimps of Curaçao, with descriptions of three new species *, Zootaxa 2372 (1), pp. 221-262 : 231-234

publication ID	https://doi.org/ 10.11646/zootaxa.2372.1.20
persistent identifier	https://treatment.plazi.org/id/3E7387F3-065A-F678-A9A5-FE6D960E80B8
treatment provided by	Felipe
scientific name	Synalpheus hoetjesi
status	sp. nov.

Treatment

Synalpheus hoetjesi View in CoL sp. nov.

( Figs. 3–9 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 , Pl. 4B–D)

Type material. Holotype: Male, CL 4.80 mm ( USNM 1128421 View Materials , original VIMS 08 View Materials CU4104), Caracas Baai , Curaçao (12°04’11.64”N, 68°51’43.59”W), from the canals of Hyattella intestinalis , 19.VI.2008 GoogleMaps . Allotype: Ov. female, CL 4.50 mm ( USNM 1128422 View Materials , original VIMS 08 View Materials CU4101), same data as holotype GoogleMaps . Paratypes: 3 non-ov. individuals, CL 3.4–4.27 mm ( USNM 1128423 View Materials , 1128424 View Materials , 1128425 View Materials , original VIMS 08 View Materials CU4103, 5, 12), 1 ov. female, CL 3.5 mm ( USNM 1128426 View Materials ), original VIMS 08 View Materials CU4106), same data as holotype GoogleMaps .

Additional material examined. Curaçao: 3 ov. females, 5 non-ov. individuals ( VIMS 08CU10101, 10401, 11901–2), Caracas Baai, from the canals of Hyattella intestinalis . 2 ov. females, 3 non-ov. individuals ( VIMS 08CU2901–2, 11501), Caracas Baai, from the canals of Xestospongia subtriangularis . 1 ov. female, 2 non-ov. individuals ( VIMS 08CU11203–4), Caracas Baai, from the canals of Xestospongia proxima . 2 ov. females, 2 non-ov. individuals ( VIMS 08CU303–3, 1804), Piscadera Baai, from the canals of H. intestinalis . 2 ov. females, 4 non-ov. individuals ( VIMS 08CU9702–4), Piscadera Baai, from the canals of X. subtriangularis . 6 ov. females, 9 non-ov. individuals ( VIMS 08CU8904, 9901–2), Piscadera Baai east, from the canals of H. intestinalis . 2 ov. females, 2 non-ov. individuals ( VIMS 08CU8601), Scary Steps, from the canals of H. intestinalis . 2 ov. females, 2 non-ov. individuals ( VIMS 08CU5601–4) and swimming larvae released from female 5603 ( VIMS 08CU5612), Westpunt, from the canals of H. intestinalis . Largest ov. female in Curaçao, CL 6.2 mm, largest non-ov. individual, CL 5.3 mm. Barbados: 1 ov. female, 1 non-ov. individual ( VIMS 08 BR 6701, 6708–1), Cement Factory (13°17’21.84”N, 59°39’27.72”W, 6–10 m depth), from the canals of H. intestinalis . 1 ov. female ( VIMS 08 BR 9603), Thunder Bay (13°13’11.16”N, 59°38’29.58”W, 2–4 m depth), from the canals of Agelas cf. clathrodes .

Description. Subcylindrical; carapace smooth, sparsely setose, posterior margin with distinct cardiac notch. Frontal margin ( Figs. 3A–B View FIGURE 3 , 4A View FIGURE 4 ): rostrum clearly narrower than ocular hoods, approximately as long as ocular hoods. Ocular hoods hoof-shaped to triangular, separated from rostrum by deep sinus. Stylocerite broadly slender, tip bluntly acute, length equal or subequal to distal margin of first segment of antennular peduncle. Basicerite without sharp spine-like tooth on dorsolateral corner, and with longer ventrolateral spine clearly overreaching 2 nd antennular peduncle. Scaphocerite acute lateral spine also clearly overreaching 2 nd antennular peduncle, typically similar in length as basicerite lateral spine (often slightly shorter or longer); blade variable, often absent on larger individuals and ovigerous females, occasionally present or vestigial on one side (<25% length of acute lateral spine). Maxilliped 3 ( Fig. 3D View FIGURE 3 ) with distal circlet of spines on distal segment and without ventrodistal spine on antepenultimate segment.

Major pereopod 1 ( Figs. 3C View FIGURE 3 , 4B–E View FIGURE 4 ) massive, fingers shorter than half-length of palm; in ventral view, outer face of fixed finger without pronounced protuberance. Palm of chela with distal superior margin produced into pronounced tubercle that bulges over downwardly directed acute spine on its ventral face. Merus, extensor margin convex, with distal angular projection. Minor pereopod 1 ( Fig. 5A–B View FIGURE 5 ) with palm about 2 times longer than high; fingers shorter than palm; dactyl with flexor margin straight, blade-like, with subdistal accessory tooth parallel to dactyl axis; transverse dorsal setal combs on extensor surface of dactyl conspicuous, with plumose setae. Fixed finger with flexor margin straight, bladelike, and with subdistal accessory protuberance.

2 nd pereopod ( Fig. 5C View FIGURE 5 ) with carpus 5-segmented, slightly longer than merus.

3 rd pereopod ( Fig. 6A–B View FIGURE 6 ) stout; dactyl biunguiculate, with clearly unequal teeth; and flexor tooth wider at base than extensor tooth; propodus with 8 mobile spines on flexor margin and 1 pair on distal end; carpus with 1 mobile distal spine; merus without any spine on flexor margin. 4 th pereopod ( Fig. 6C–D View FIGURE 6 ) similar to 3 rd, but with 7 mobile spines on flexor margin. 5 th pereopod ( Fig. 6E–F View FIGURE 6 ) similar to 4 th, but without distal spine on carpus, and with 7 transverse combs of stout setae on ventral face of propodus.

Pleura 1 of male ( Fig. 7B View FIGURE 7 ) with posterior corner produced ventrally and anteriorly, hook-like; 2 nd pleura of male with posterior corner broadly rounded; 3 rd to 5 th pleura with posterior margin forming blunt acute angle.

Telson ( Fig. 7C View FIGURE 7 ), mesial pair of distal telson spines distinctly stouter than lateral pair, relative length of mesial vs. lateral distal telson spines ranges from subequal to strongly unequal (mesial spines longer than lateral).

Uropods with 4–6 fixed teeth on outer margin of exopod anterior to moveable spine.

Color. Live specimens range from drab to orange-tinged; ovigerous females have brilliant orange ovaries, embryo color ranges from reddish-brown to chestnut-colored.

Etymology. We are honored to name this species after Dr. Paul Hoetjes, who was one of the first to examine cryptofaunal sponge communities in Curaçao ( Westinga & Hoetjes 1981) and who provided invaluable assistance to us during this expedition.

Hosts and ecology. Synalpheus hoetjesi was found most frequently in the sponge Hyattella intestinalis and (less frequently) in Xestospongia proxima and Xestospongia subtriangularis (see notes above). S. hoetjesi has also been recorded from the sponges Hyattella intestinalis and Agelas cf. clathrodes in Barbados ( Table 2).

Distribution. Curaçao (this study), Barbados (this study).

Remarks. This species is morphologically and phylogenetically most closely related to Synalpheus ul and Synalpheus yano , but is distinguishable from them by host use, size, and several morphological characteristics. S. hoetjesi can be distinguished from S. yano by the posterior corner of the male 2 nd pleura (which forms an obtuse angle in S. yano and is broadly rounded in S. hoetjesi ) and by the relative thickness of the distal telson spines (medial spines clearly thicker and stouter than lateral spines in S. hoetjesi , but equal or subequal in thickness in S. yano ). In Curaçao, where S. hoetjesi co-occurs with S. ul, S. hoetjesi was most often found in Hyattella intestinalis , and was very easy to differentiate from S. ul living in Hymeniacidon caerulea and Agelas cf. clathrodes . In the latter hosts, S. hoetjesi is easily distinguishable from S. ul by body size ( S. hoetjesi mean CL 4.70 mm, S. ul mean CL 3.36 mm), scaphocerite blade (absent or vestigial in S. hoetjesi , present and ~20–75% the length of the scaphocerite in S. ul), shape of the distal superior margin in the major chela (bulging over the accessory spine in S. hoetjesi , gently sloping in S. ul), and thickness of distal telson spines (mesial> lateral in S. hoetjesi , mesial ~ lateral in S. ul). Additionally, specimens identified as S. ul based on the COI gene tree were never found in H. intestinalis , and specimens identified as S. hoetjesi based on COI were never found in Hymeniacidon or Agelas , suggesting (along with aforementioned differences in morphology) that these species are clearly delineated in these hosts. However, although S. hoetjesi formed a distinct clade in the mitochondrial COI gene tree ( Fig. 8 View FIGURE 8 ), individuals of S. hoetjesi from hosts other than Hyattella intestinalis were more difficult to distinguish morphologically from Synalpheus ul ( Fig. 9). In particular, sponges in the genus Xestospongia ( Xestospongia sp. “soft”, X. proxima , and X. subtriangularis ) hosted both S. ul and S. hoetjesi as identified using the COI gene tree ( Fig. 8 View FIGURE 8 ), but these individuals sometimes exhibited ambiguous characters ( Fig. 9). S. hoetjesi from X. subtriangularis usually possessed the bulging major chela protuberance typical of S. hoetjesi from H. intestinalis , but often had distal telson spines that were nearly equal in thickness, which is otherwise typical of S. ul. Likewise, S. ul from X. subtriangularis and Xestospongia sp. “soft”, often had distal telson spines equal in thickness, but sometimes had major chela protuberances that approached the “bulge” characteristic of S. hoetjesi . Close phylogenetic relationships between S. hoetjesi and S. ul, along with convergence of morphological characters in sponge hosts in which these two species co-occurred, suggests these species may be hybridizing in these hosts, although additional genetic analyses with nuclear markers are necessary to confirm this hypothesis.