Automate isabelae Ramos-Tafur 2018
Creators: name: Anker, Arthur
name: Tavares, Marcos
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Automate
Automate isabelae

description: Automate isabelae Ramos-Tafur, 2018
(Figs. 1–3)
Material examined. Brazil, São Paulo, Projeto Biota Araçá, Canal de São Sebastião, A.C.Z. Amaral coll.: 1 non-ovig. specimen (cl 5.1 mm), MZUSP 35387, Stn 30, 23°48′49″S 45°23′51″W, VV, 10 m, 10.x.2012; 1 non-ovig. specimen (cl 3.5 mm), MZUSP 35217; Stn 67(4), 23°48′49″S 45°23′51″W, MC, 10 m, 19.ii.2013; 1 non-ovig. specimen (cl 4.3 mm), MZUSP 33932, Stn 141(1), 23°48′49″S 45°23′51″W, MC, 10 m, 15.x.2013; 1 ovig. female (cl 5.6 mm), MZUSP 35198, Stn 26, 23°49′8″S 45°24′11″W, VV, 10 m, 09.x.2012; 1 non-ovig. specimen (cl 4.4 mm), MZUSP 33981, Stn 27H, 23°49′08″S 45°24′11″W, VV, 10 m, 08.vii.2014; 1 non-ovig. specimen (cl 4.9 mm), MZUSP 35207, Stn 32(3), 23°49′07″S 45°24′47″W, MC, 15 m, 09.x.2012; 1 non-ovig. specimen (possibly male) (cl 3.3 mm), MZUSP 33933, Stn 110(1), 23°49′03″S 45°23′52″W, MC, 20 m, 12.vi.2013; 2 non-ovig. specimens (larger possibly male) (cl 3.6 mm, 5.1 mm), MZUSP 33747, Stn 30H, 23°49′07″S 45°24′47″W, VV, 15 m, 08.vii.2014; 1 non-ovig. specimen (cl 4.6 mm, missing major P1*), MZUSP 35397, Stn 36, 23°49′03″S 45°23′52″W, VV, 20 m, 08.x.2012; 1 juv. specimen (cl indet.*), MZUSP 37306, Stn 66, 23°49′55″S 45°23′58″W, VV, 10 m, 19.ii.2013; 2 non-ovig. specimens (cl 4.3 mm, missing both P1*, cl 6.0 mm), MZUSP 35402, Stn 140(2), 23°49′55″S 45°23′58″W, MC, 10 m, 14.x.2013; 1 non-ovig. specimen (cl 4.7 mm, missing major P1*), MZUSP 35230, Stn 148, 23°49′03″S 45°23′52″W, VV, 20 m, 14.x.2012 [tentative identifications marked with an asterisk*].
Description. See Ramos-Tafur (2018) for original description and illustrations, and Figs. 1–2 for complementary illustrations of the Brazilian material.
Colour in life. Body translucent with beige or pale-yellow tinge; mid-section and posterior fourth of carapace, pleon (except for dorsal part of sixth pleonite), eyestalks and antennular peduncles with very large, dendritic, dark red chromatophores; chelipeds pale-yellow, except for white distal halves of fingers (Fig. 3).
Distribution. Presently known only from the western Atlantic: southern and southwestern Florida, USA (24°N), and Araçá Bay (23°S), São Paulo, Brazil.
Ecology. In Araçá Bay, A. isabelae was found at depths ranging from 10 m to 20 m in soft sediments mainly characterised by high silt/clay and organic matter component.
Remarks. The Brazilian material herein assigned to A. isabelae agrees in most aspects with the type specimens from Florida, as described and illustrated by Ramos-Tafur (2018). Most importantly, A. isabelae from Florida and Brazil are very similar in the shape and armature of the major chela (cf. Fig. 2A, B, E, F; Ramos-Tafur 2018: figs. 2A, B; 3A–C). They also share many diagnostic characters of the frontal region (rostrum, eyestalks, antennular and antennal peduncles), third maxilliped, minor cheliped, second and third pereiopods, and tail fan (cf. Figs. 1, 2; Ramos-Tafur 2018: figs. 1–4). The only significant discrepancy between the type specimens and the material from Brazil is the presence of a small spiniform seta on the fifth pereiopod ischium in the Brazilian specimens (Fig. 1H); according to Ramos-Tafur (2018), this article is unarmed in the type specimens from Florida (“without spine on ischium”). However, the illustration of the fifth pereiopod in Ramos-Tafur (2018: fig. E) shows an appendage that most likely does not belong to the holotype (cf. Fig. 1H); as a matter of fact, it appears to be a non-alpheid pereiopod (see also below). A slight difference can be noted in the rostral projection, which appears to be smaller in the type specimens compared to that of the Brazilian specimens (cf. Fig. 1 A, Ramos-Tafur 2018: figs. 1A, 4B).
The previously unknown colour pattern of A. isabelae, which herein is illustrated for the first time (Fig. 3), appears to be diagnostic for the species. Particularly remarkable is the large size and almost exaggerated dendritic form of the dark red chromatophores on the pleon. This colour pattern has some similarities with that of specimens preliminarily identified as A. evermanni from both coasts of Panama, which have smaller and differently distributed red chromatophores (Anker, pers. obs.).
Ramos-Tafur (2018) described A. isabelae without a direct comparison with material of A. rugosa. The author listed several differences between A. isabelae and A. rugosa, more precisely in the proportions of the third maxilliped and major cheliped, in the carpus of the minor cheliped, and in the armature of the third pereiopod propodus and telson. However, all these differences were derived from Wicksten’s (1981) illustrations, which do not seem to be overly accurate. Most unusual and intriguing is the absence of spiniform setae on the dorsal surface of the telson in A. rugosa, according to Wicksten’s (1981) redescription (“dorsal surface unarmed”) and illustration (her fig. 1, general habitus). In his original description of A. rugosa, which has no illustrations, Coutière (1902) stated: “La 2 e paire et le telson, comme chez A. Evermanni. Le telson, toutefois, ne présente pas la longue soie médiane et dorsale de cette dernière espèce”. This author, while noting that A. evermanni differs from A. rugosa by the presence of a long, plumose, median, dorsal seta (Rathbun 1901: fig. 22e, f), did not comment on the absence of spiniform setae in A. rugosa, which would be very atypical condition for an alpheid shrimp and therefore worth mentioning. Furthermore, in A. evermanni, the dorsal surface of the telson does have two pairs of small spiniform setae, as illustrated by Rathbun (1901: fig. 22e) and Dworschak & Coelho (1999: fig. 31). These facts taken together seem to suggest that (1) Wicksten’s (1981) redescription of A. rugosa may contain some errors, and (2) consequently, at least some differentiating characters between A. isabelae and A. rugosa listed by Ramos-Tafur (2018) may not be valid or at least need to be confirmed by a direct comparison of the eastern Pacific and eastern Atlantic material. At our request, Dr. Michel E. Hendrickx (Universidad Autónoma de México, Mazatlán, UNAM) examined several specimens of A. rugosa and confirmed the presence of two or three small spiniform setae on the dorsal surface of the telson in some of them (M.E. Hendrickx, pers. comm., June 2024), which thus invalidates an important differentiating character used by Ramos-Tafur (2018) to separate A. isabelae from A. rugosa. In addition, some illustrations provided by Ramos-Tafur (2018) are clearly diagrammatic and may perhaps not be accurate.
Automate isabelae is the fourth species of Automate reported from Brazil, after A. dolichognatha (s. lat.), A. evermanni (s. lat.) and A. rectifrons (Pires-Vanin et al. 1997; Christoffersen 1998 and references therein; Soledade et al. 2015, as A. cf. rectifrons; Almeida et al. 2018 and references therein, as A. cf. rectifrons). Dworschak & Coelho (1999) reported A. evermanni from Praia do Araçá, very near the localities where the present material of A. isabelae was collected. Ramos-Tafur (2018) also found body parts of a specimen identified as A. cf. evermanni in a fish stomach in southern Florida, indicating that both species may occur in sympatry over large areas in the western Atlantic, being separated by depth and perhaps other ecological factors (sediment type, possible symbioses). It must be noted that the two species are difficult to separate in the absence of the major cheliped. Rathbun (1901: fig. 22e, f) illustrated a long plumose seta arising from the posterior dorsal surface of the telson in one of the type specimens of A. evermanni. In A. isabelae, the dorsal surface of the telson has several erect setae (Fig. 1B), but apparently no plumose seta in its posterior section, as in A. evermanni sensu Rathbun (1901). Noteworthy, the Brazilian specimens herein tentatively assigned to A. cf. evermanni also do not have a dorsally arising plumose seta near the posterior margin of the telson, although it must be kept in mind that this structure is very fragile and may easily break off. Holthuis (1951), reporting West African material of A. evermanni only mentioned “one pair of feathered setae” originating from the posterior margin, but no dorsally arising plumose seta, as illustrated by Rathbun (1901: fig. 22e, f). Therefore, all material previously identified as A. evermanni (e.g., Holthuis 1951; Crosnier & Forest 1966; Chace 1972; Dworschak & Coelho 1999; De Grave & Anker 2017) and the present material of A. cf. evermanni will need to be carefully reassessed. The record of A. rectifrons from São Sebastião (municipality of Praia do Araçá) by Pires-Vanin et al. (1997) was briefly addressed by Almeida et al. (2018). Generally, all Brazilian records of A. rectifrons or A. cf. rectifrons, but also those of A. dolichognatha and A. evermanni (see above) require confirmation. At least the latter two species may represent wide-spread species complexes (De Grave & Anker 2017).
description: Published as part of Anker, Arthur & Tavares, Marcos, 2024, The first record of the alpheid shrimp Automate isabelae Ramos-Tafur, 2018 from Brazil (Decapoda: Caridea), pp. 594-600 in Zootaxa 5506 (4) on pages 595-599, DOI: 10.11646/zootaxa.5506.4.9, http://zenodo.org/record/13747519