Aclis sarissa Watson, 1881

Souza, Leonardo Santos De, Araújo, Tarciso Almeida De & Pimenta, Alexandre Dias, 2024, Taxonomic review of Aclis Lóven, 1846 (Gastropoda, Eulimidae) from Brazil with notes on other congeners from the western Atlantic and Saint Helena, Zootaxa 5433 (4), pp. 451-499 : 458-461

Aclis sarissa Watson, 1881

Figs 2 , 3

Aclis sarissa Watson, 1881: 247 ; Watson (1886: 503, pl. 34, Fig. 3 ); Rios (1975: 62, pl. 16, Fig. 246); Rios (1985: 52, pl. 19, fig. 235); Rios (1994: 106, pl. 34, fig. 439); Rios (2009: 197, fig. 488).

Aclis carolinensis Bartsch, 1911: 438 , pl. 59, fig. 7. New synonymy.

Hemiaclis sarissa : Bartsch (1947: 27, pl. 6, Fig. 6 .)

Hemiaclis carolinensis : Bartsch (1947: 25, pl. 6, Fig. 4 ).

Type material. Lectotype (herein designated and examined): NHMUK 1887.2.9.1576; H.M.S. Challenger coll., 10/xi/1873 . Paralectotypes (herein examined): Brazil: Pernambuco state: type locality: NHMUK 1887.2 . 9.1577 [1]; type locality: NMW 1955.158 .26255 [3]. Holotype of Aclis carolinensis (herein examined): USA: North Carolina state, Cape Hatteras , USFC sta. 2595; 35°08′00″N, 75°05′30″W, 115 m; Steamer Albatross col., 17/x/1885: USNM 83743 [3] .

Type locality. Brazil: Pernambuco state: Challenger sta. 122 ; 09°05′S, 34°50′W, 640 m.

Material examined. The types and: USA: Florida state: off West Dry Rocks Reef, Eolis sta. 320; ~ 24°26′46″N, 81°55′37″W, 146 m; Yacht Eolis col., 1916: USNM 503753 [5]; off Fowey Rocks Lighthouse, Eolis sta. 355; ~ 25°35′27″N, 80°05′48″W, 128 m; Yacht Eolis col., 1916: USNM 503763 [11]; off Fowey Rocks Lighthouse, Eolis sta. 364; ~ 25°35′27″N, 80°05′48″W, 137–165 m; Yacht Eolis col., 1917: USNM 503771 [11]; Brazil: Pernambuco state: Revizee Nordeste ; 08°46′00″S, 34°44′00″W, 690 m; R/ V Natureza col., 18/xi/2000: MORG 49199 [4†]; Sergipe state: MARSEAL SED 3 sta. BN6: CZUFS GAS-00102 [1]; MARSEAL SED 3 sta. DN4: CZUFS GAS-00103 [1]; MARSEAL SED sta. GN4: CZUFS GAS-00104 [1].

Revised description. Shell vitreous or whitish, tall, conical, with an obtuse apex, reaching about 3.2 mm long, 1.1 mm wide. Protoconch globose, subcylindrical, about 2.0 whorls, about 300 μm wide, smooth, transition to teleoconch marked by a gentle incremental scar. Teleoconch reaching eight whorls, strongly convex outline, faster increase in diameter from the fourth whorl; suture deep, well impressed, sloping; surface glossy, presenting faint microscopic spiral threads in subsutural zone of each whorl; incremental scars slightly demarcated appearing at irregular intervals; growth lines slightly demarcated; surface smooth or with up to three faint spiral keels. Last whorl about 40% of total length, broad; base rounded or slightly crenulated by spiral keels. Aperture round to elliptical in shape, about 60% of body whorl length, strongly expanded laterally, rounded and slightly advanced anteriorly, acute posteriorly; outer lip thin, slightly opisthocline, gradually advancing forward, rectilinear; inner lip thin, reflected. Umbilical fissure present.

Measurements. Lectotype (NHMUK 1887.2.9.1576): 8 whorls; SL= 3.21 mm; BWL= 1.38 mm; AL= 0.81 mm; SW= 1.14 mm; AW= 0.66 mm. NMW 1955.158.26255: 8 whorls; SL= 4.29 mm; BWL= 1.67 mm; AL= 1.02 mm; SW= 1.67 mm; AW= 0.77 mm.

Remarks. Watson (1881) did not state the exact number of individuals on which the description was based. There are two shells housed at the NHMUK collection, which are considered as syntypes ( Fig. 2A–E ). Other shells from the same locality and labeled as A. sarissa by J.C. Melvill are housed at the NMW. According to Lingwood (1981), part of the material from the Challenger expedition was distributed to collections in other museums. By the experience of H. Wood and G. Oliver (curators at the NMW; pers. Comm) on the Melvill-Tomlin collection, the Challenger material from this institution usually belongs to the type series of Watson’s species, as Melvill and Watson were contemporaries. Thus, we consider the three shells of NMW 1955.158.26255 as syntypes (one illustrated in Fig. 2F–I ). The shell of NHMUK 1887.2.9.1576 ( Fig. 2A–C, E ) is undoubtedly the specimen figured by Watson (1886: 503, pl. 34, Fig. 3 ) and is here selected the lectotype to stabilize the concept of the species.

Watson (1881) described a faint spiral sculpture in A. sarissa , which seems variable like in the type species Aclis minor ( Fretter & Graham 1982: Figs. 282, 283). The paralectotype from the NMW ( Fig. 2F–H ) have more pronounced spiral keels than the lectotype ( Fig. 2A–C ). This variation in the expression of the spiral keels was also observed in the non-type material examined here ( Fig. 3A–G ), which can be possibly accentuated by the state of preservation of the shell, since in eroded shells, the keels become vary faint. The spiral keels are more frequent and more notable in the anterior whorls ( Figs 2G, H , 3E–H ), a pattern which is also common in A. minor ( Gofas et al. 2011: 225, text-fig).

Since the original description, there was no published record of new material of A. sarissa . In the present study, additional records from the northeast of Brazil are provided, and the geographic distribution of the species is extended to the southeast of Brazil. These additional specimens of A. sarissa present a similar shell shape ( Fig. 3A–F ) to the lectotype and have a small variation of the teleoconch sculpture ( Fig. 3A–H ). The aperture varies from circular ( Fig. 3A, C ) to oval and more advanced anteriorly ( Fig. 3E, G ). The bathymetric range of the species is also extended upward (225 m) and downward (1000 m) but based exclusively on empty shells.

Barros et al. (2001) commented that A. sarissa would be a possible synonym of Costaclis hyalina (cited as “ Hemiaclis hyalina ”) based on shells from the northeast Brazil. However, Barros et al. (2001, 2003) presented confused ideas about these species. During the examination of the LMUFRPE collection, no voucher material studied by Barros et al. (2001; 2003) could be found, but the shell figured by Barros et al. (2001: Fig. 2D ) is a misidentification of a newly described species of the present study (see Aclis pulchra nov. sp.), while the shell figured by Barros et al. (2003: Fig. 1 ) is a young specimen and it is not possible to infer a precise determination. Aclis sarissa and C. hyalina are distinct species because A. sarissa does not present axial ribs like C. hyalina , it has a more globular protoconch and more convex teleoconch whorls.

Aclis sarissa is herein considered as a senior synonym of Aclis carolinensis Bartsch, 1911 , from North Carolina, USA. The holotype of A. carolinensis (USNM 83743; Fig. 2J–K ) has a similar shape, spire angle, broad aperture expanded laterally, a quite smooth teleoconch and an umbilical fissure; additional shells from Florida, USA, has a variation from smooth to three faint spiral keels at the body whorl. It is hardly discernible from the material examined of A. sarissa , except for the more sinuous outline of outer lip. However, the latter feature is difficult to compare since most specimens have a partially broken outer lip. Considering the variation of sculpture in A. sarissa , the quite smooth surface also fits the taxon.

Bartsch (1947) transferred both Aclis sarissa and Aclis carolinensis to Hemiaclis G.O. Sars, 1878 , which is the current classification in MolluscaBase (2021a). Bartsch (1947) did the same for several other species previously assigned in Aclis , but as noted by Bouchet & Warén (1986), many of them do not belong with certainty in Hemiaclis . Hemiaclis embraces species with a broadly conical shell with whorls increasing in diameter regularly, sutures relatively flat and a straight outer lip seen in lateral view ( Bouchet & Warén 1986). Furthermore, the species of Hemiaclis have a smooth teleoconch, lacking keels, ribs and microscopic spiral striae.

Geographic Distribution. USA: North Carolina, Florida; Brazil: Pernambuco, Sergipe. From 115 to 1000 m.

Figures

FIGURE 1. Terminology of some of the shell features used in descriptions in the present study. A. Microscopic spiral striae of the teleoconch indicated by arrows. B. Spiral keels of the teleoconch indicated by arrows. C. Umbilical fissure indicated by arrow. D. Umbilicus indicated by arrow.

FIGURE 2. Aclis sarissa Watson, 1881. A–C, E. Lectotype, NHMUK 1887.2.9.1576, herein designated; D. Paralectotype, NHMUK 1887.2.9.1576; F–I. Paralectotype, NMW 1955.158.26255; J–K. Holotype of Aclis carolinensis, USNM 83743. A, D, F, J. Shell in frontal view; B, G, K. Shell in lateral view. C, H. Shell in dorsal view. E, I. Body whorl in frontal view. Scale bars: A–D, F–H, I–J. 1 mm; E, I. 500 μm. Credits: A–E. NHMUK photographic unit; F–I. NMW.

FIGURE 3. Aclis sarissa Watson, 1881. A–B, H–K. MORG 49199. C–D. CZUFS GAS-00102. E–G. CZUFS GAS-00104. A, C, E. Shell in frontal view; square in A indicates detail in I. B, D, F. Shell in lateral view. G–H. Detail of the body whorl in frontal view. I–J. Detail of teleoconch surface; rectangle in I indicates detail in J. K. Detail of apical whorls; arrow indicates the transition protoconch–teleoconch. Scale bars: A–F. 1 mm; G–H. 500 μm; I–J. 50 μm; K. 200 μm.

FIGURE 4. Aclis watsoni Barros, Lima & Francisco, 2007. A–B. CZUFS GAS-00105. A. C. Shell in frontal view. B. Shell in lateral view. Scale bar: 1 mm.

FIGURE 6. Aclis sp. 1: MNRJ 33505. A. Shell in frontal view. B. Apical whorls: double arrows indicate microscopic and sigmoid axial line at the protoconch surface, single bottom arrow indicate microscopic spiral striae at the teleoconch surface. C. Body whorl. Scale bars: A. 1 mm; B. 200 μm; C. 500 μm.