Typton distinctus Chace, 1972

Moraes, Isabela R. R., Bergamasco, Giovanna R., Santos, Rafael C., Antunes, Mariana, Soledade, Guidomar O., Costa, Rogerio C. & Castilho, Antonio L., 2020, New record of the sponge-dwelling shrimp Typton distinctus Chace, 1972 (Decapoda: Caridea: Palaemonidae) in São Paulo State, Brazil, Zootaxa 4763 (3), pp. 444-446 : 444-445

Typton distinctus Chace, 1972

( Figure 1B, C )

Typton distinctus— Chace 1972: 49 , figs. 13, 14; Abele & Kim 1986: 17, 189, figs. d–g; Camp 1998: 140; Ramos-Porto & Coelho 1998: 340; Coelho et al. 2006: 51; Duris et al. 2009: 1056; Souza et al. 2011: 45; Vieira et al. 2012: 31; Pachelle et al. 2015: 319.

Typton carneus — Holthuis, 1951 pro parte: 162, pl. 51, figs. b–d, f–j, m–o [not T. carneus Holthuis, 1951 , pl. 51, figs a, e, k, l].

Typton sp .— Coelho & Ramos-Porto, 1972: 146.

Material examined: 1 male (Carapace Length: 2.37 mm), Cais do Porto in Itaguá—Ubatuba, 23º27’05” S 45º02’48” W,

Coll. Moraes & Santos, January/2019, MZUSP 40095; 1 female (Carapace Length: 1.53 mm), Cais do Porto—Ubatuba,

23º27’05” S 45º02’48” W, Coll. Moraes & Santos, March/2019, MZUSP 40096. Material not deposited into the Museum

can be found in the Biological collection from São Paulo State University—Zoology Department, Botucatu-SP: 2 males,

1 female, 1 ovigerous female (Carapace Length Size: Size range: 1.53 ≤ CL ≤ 2.71 mm. Mean CL = 2.30 ± 0.47 mm),

23º27’05” S 45º02’48” W ,, Cais do Porto—Ubatuba, 23º27’05” S 45º02’48” W, Coll. Moraes & Santos, January/2019.

Description: For original descriptions and illustrations see Chace (1972); additional figures see Holthuis (1951) as Typton carneus pl. 51.

Distribution: Western Atlantic: USA (Florida), Mexico (Bahía de la Ascensión), Cuba (Los Arroyos), Brazil (Pernambuco, Rio de Janeiro, São Paulo) ( Camp et al. 1998; Chace 1972; Coelho-Filho 2006; Pachelle et al. 2015; present study).

Remarks: The second pair of pereiopods developed is a taxonomic characteristic of Palaemonidae shrimps, and was recognized as the most remarkable morphological feature of T. distinctus . The movable finger forms a pointed hook twist- ed into plane nearly perpendicular to that of palm ( Chace, 1972) (Figure 2B, C). Pachelle et al. (2015) described some additional morphological features used to distinguish T. distinctus from a very similar conspecific, T. carneus : rostrum not “deepening” near midlength, the less produced ventral margin of the major chela carpus, and the mandible with a reduced incisor process. All characters were observed in our material and corroborate its identification as T. disctinctus .

Despite being recognized as “sponge-dwelling shrimps”, the Typton genera does not present a species-specific relationship with any demosponges and can be found in association with many species of this host. In São Paulo state, T. fapespae has been reported living inside Mycala angulosa ( Almeida et al. 2014), and in the present study, T. distintus was found in Dragmacidon reticulatus . Typton distinctus has also been found in association with other sponges from the Tedania genus.

Another important aspect of this relationship is the shrimp’s intense orange-red color that matches its sponge host, which has already been observed in other shrimp/sponge associations. Therefore, despite not being a specific relationship, the color criteria must be carefully observed when analyzing these materials. The distribution of shrimps among sponge-hosts suggests that Typton shrimps actively prevent colonization by conspecifics in their sponges, protecting their resources and reducing damage to the hosts, as they are adapted to consuming spongy tissues and sequestering their host pigments ( Ďuriš et al. 2011).

This new register in São Paulo state and the characterization of the host and shrimp provides a new perspective for studies focused on characterizing the type of symbiosis present between pontoniinaes and demosponges.

Figures

FIGURE 1. The sponge host Dragmacidon reticulatum (Ridley & Dendy, 1886), in panoramic view (A) Photo by:Antunes, M., and its associated shrimp Typton distinctus Chace, 1972, in lateral (B) and dorsal (C) view. Scale bar indicates 1cm. Photos By Moraes IRR.